Medullary Thyroid Carcinoma

MONDO:0015277 Pathograph 7 thyroid carcinoma

Medullary thyroid carcinoma (MTC) is a neuroendocrine malignancy arising from the parafollicular C-cells of the thyroid gland. Approximately 25% of cases are hereditary, caused by germline RET proto-oncogene mutations in MEN2A, MEN2B, or familial MTC syndromes. Sporadic MTC frequently harbors somatic RET mutations, while RET-wild-type tumors can be driven by RAS-family alterations. MTC secretes calcitonin and carcinoembryonic antigen (CEA), providing useful biomarkers. The identification of RET as the driver oncogene led to development of selective RET inhibitors like selpercatinib and pralsetinib.

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0
Mappings
0
Definitions
0
Inheritance
4
Pathophysiology
1
Histopathology
7
Phenotypes
7
Pathograph
4
Genes
5
Treatments
3
Subtypes
0
Differentials
0
Datasets
0
Trials
0
Models
8
References
2
Deep Research
🏷

Classifications

Harrison's Chapter
cancer solid tumor
ICD-O Morphology
Carcinoma
◆

Subtypes

3
Hereditary MTC (MEN2A)
Associated with MEN2A syndrome caused by germline RET mutations in the extracellular cysteine-rich domain. Patients develop MTC, pheochromocytoma, and primary hyperparathyroidism. Prophylactic thyroidectomy is recommended.
Hereditary MTC (MEN2B)
Associated with MEN2B syndrome caused by germline RET M918T mutation in the kinase domain. Most aggressive form with mucosal neuromas, marfanoid habitus, and very early MTC onset. Pheochromocytoma also occurs.
Sporadic MTC
Approximately 75% of MTC cases are sporadic without germline RET mutations. Somatic RET mutations occur in 40-50% of sporadic cases, and RAS-family mutations are important alternative drivers in RET-wild-type sporadic MTC. Generally presents later than hereditary forms.
⚙

Pathophysiology

4
RET Proto-Oncogene Activation
Activating mutations in the RET receptor tyrosine kinase lead to constitutive kinase activity without ligand binding. This drives downstream signaling through RAS-MAPK and PI3K-AKT pathways, promoting C-cell proliferation and survival.
parafollicular cell link
RET receptor tyrosine kinase signaling link ↑ INCREASED
thyroid gland link
Downstream
RAS-MAPK Pathway Activation RET phosphorylation activates RAS-RAF-MEK-ERK cascade driving proliferation
PI3K-AKT Pathway Activation RET phosphorylation recruits PI3K leading to AKT-mediated survival
Show evidence (2 references)
PMID:15355445 SUPPORT
"hereditary should be determined by a direct analysis of the RET proto-oncogene"
Review confirms RET proto-oncogene analysis is central to MTC characterization, supporting the role of RET activation in pathogenesis.
PMID:34292174 SUPPORT
"understanding of some of the driver mutations in MTC allows for therapeutics"
Recent review confirms that driver mutations (primarily RET) are central to MTC pathogenesis and therapeutic targeting.
RAS Mutation-Driven Proliferation
Somatic RAS-family mutations provide an alternative oncogenic driver in RET-wild-type sporadic MTC. Activating HRAS, KRAS, or NRAS lesions converge on MAPK and PI3K-AKT signaling to sustain C-cell proliferation and survival.
HRAS link KRAS link NRAS link
MAPK cascade link ↑ INCREASED phosphatidylinositol 3-kinase signaling link ↑ INCREASED
Downstream
RAS-MAPK Pathway Activation Activating RAS mutations directly feed the MAPK cascade.
PI3K-AKT Pathway Activation RAS signaling can also engage PI3K-AKT survival signaling.
Show evidence (1 reference)
PMID:21325462 SUPPORT Human Clinical
"68.0% (17 of 25) of the RET-negative MTC and in only 2.5% of the RET-positive"
Sequencing of sporadic MTC demonstrates that RAS mutations are enriched in RET-negative tumors, supporting a distinct RAS-driven pathophysiology node.
RAS-MAPK Pathway Activation
RET activation or activating RAS-family mutations stimulate the RAS-RAF-MEK-ERK signaling cascade, driving uncontrolled C-cell proliferation. This pathway is a major effector of RET- and RAS-mediated transformation in MTC.
MAPK cascade link ↑ INCREASED
PI3K-AKT Pathway Activation
RET activation recruits PI3K and activates the PI3K-AKT-mTOR signaling cascade, promoting C-cell survival and resistance to apoptosis. This cooperates with MAPK signaling to drive MTC tumorigenesis.
phosphatidylinositol 3-kinase signaling link ↑ INCREASED
✶

Histopathology

1
Medullary Thyroid Carcinoma VERY_FREQUENT
Medullary thyroid carcinoma originates from parafollicular C cells.
Show evidence (1 reference)
PMID:15355445 SUPPORT Human Clinical
"produce calcitonin (CT), and accounts for 5-10% of all thyroid cancers"
Review abstract directly identifies parafollicular/C-cell origin for standard MTC.
⬡

Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.
Pathograph: causal mechanism network for Medullary Thyroid Carcinoma Interactive directed graph showing how pathophysiology mechanisms, phenotypes, genetic factors and variants, experimental models, environmental triggers, and treatments relate through causal and linked edges.
●

Phenotypes

7
Cardiovascular 1
Lymph Node Metastasis FREQUENT Lymphadenopathy (HP:0002716)
Digestive 1
Diarrhea FREQUENT Diarrhea (HP:0002014)
Show evidence (1 reference)
DOI:10.1159/000508850 SUPPORT Human Clinical
"Tumoral secretion of various molecular factors, such as calcitonin (Ct), can cause diarrhea in patients with medullary thyroid cancer (MTC)."
Case-series abstract directly attributes diarrhea to tumor-secreted factors in MTC, replacing the prior indirect placebo-arm adverse-event evidence.
Endocrine 3
Thyroid Nodule VERY_FREQUENT Thyroid carcinoma (HP:0002890)
Show evidence (1 reference)
PMID:34292174 SUPPORT
"of thyroid nodules has improved the diagnostic accuracy of MTC"
Confirms that thyroid nodules are the primary clinical presentation of MTC, assessed via cytology.
Pheochromocytoma FREQUENT Pheochromocytoma (HP:0002666)
Show evidence (2 references)
PMID:33812987 SUPPORT
"carcinoma (MTC), phaeochromocytoma, primary hyperparathyroidism, cutaneous"
Confirms pheochromocytoma as a key feature of both MEN2A and MEN2B syndromes.
PMID:15355445 SUPPORT
"disease extent should be evaluated, phaeochromocytoma and"
Review lists pheochromocytoma among the clinical implications to address after MTC diagnosis.
Primary Hyperparathyroidism OCCASIONAL Hyperparathyroidism (HP:0000843)
Show evidence (1 reference)
PMID:33812987 SUPPORT
"carcinoma (MTC), phaeochromocytoma, primary hyperparathyroidism, cutaneous"
Confirms primary hyperparathyroidism as a component of MEN2A syndrome.
Integument 1
Flushing OCCASIONAL Flushing (HP:0031284)
Show evidence (1 reference)
PMID:31885947 SUPPORT Human Clinical
"causing systemic manifestation in the form of flushing, diarrhea, and"
Case-report abstract directly lists flushing as a systemic manifestation of MTC hormone secretion.
Other 1
Elevated Serum Calcitonin VERY_FREQUENT Elevated circulating calcitonin concentration (HP:0003528)
Show evidence (2 references)
PMID:26494386 SUPPORT
"pg/mL are highly indicative for the diagnosis MTC"
Confirms elevated calcitonin as a highly specific diagnostic marker for MTC.
PMID:15355445 SUPPORT
"produce calcitonin (CT), and accounts for 5-10% of all thyroid cancers"
Confirms that MTC arises from calcitonin-producing C cells, explaining the characteristic elevated calcitonin levels.
🧬

Genetic Associations

4
RET (Germline and Somatic Activating Mutations)
Autosomal Dominant
Show evidence (2 references)
PMID:32846061 SUPPORT
"RET mutations occur in 70% of medullary thyroid cancers, and RET"
Confirms high prevalence of RET mutations in MTC (70% including both hereditary and sporadic cases).
PMID:33812987 SUPPORT
"dominant hereditary cancer syndrome due to germline variants in the REarranged"
Confirms autosomal dominant inheritance pattern of hereditary MTC through germline RET variants.
HRAS (Somatic activating mutations in RET-negative sporadic MTC)
Show evidence (1 reference)
PMID:21325462 SUPPORT Human Clinical
"Somatic H-RAS and K-RAS mutations were detected in 14 of 25 (56.0%) and"
Supports HRAS as the predominant RAS-family alteration detected in RET-negative sporadic MTC.
KRAS (Somatic activating mutations in RET-negative sporadic MTC)
Show evidence (1 reference)
PMID:21325462 SUPPORT Human Clinical
"Somatic H-RAS and K-RAS mutations were detected in 14 of 25 (56.0%) and"
Supports KRAS as a recurrent RAS-family alteration in RET-negative sporadic MTC.
NRAS (Somatic RAS-family alterations in sporadic MTC)
Show evidence (1 reference)
DOI:10.3390/cancers15194865 SUPPORT Human Clinical
"other genetic alterations such as RAS family (HRAS, KRAS, NRAS) genetic alterations"
Recent review includes NRAS within the RAS-family genetic alterations relevant to MTC natural history.
💊

Treatments

5
Thyroidectomy
Action: surgical procedure MAXO:0000004
Total thyroidectomy with central neck dissection is the primary treatment for MTC. In hereditary cases, prophylactic thyroidectomy is recommended based on genotype, often in early childhood for MEN2B.
Selpercatinib
Action: targeted therapy Ontology label: Targeted Therapy NCIT:C93352
Agent: selpercatinib ↗
Highly selective RET inhibitor approved for RET-mutant MTC. Demonstrates remarkable efficacy with durable responses in both treatment-naive and previously treated patients. Generally well-tolerated.
Show evidence (1 reference)
PMID:32846061 SUPPORT
"response was 73% (95% CI, 62 to 82), and 1-year progression-free survival was"
The LIBRETTO-001 trial demonstrated that selpercatinib achieves 73% response rate and 92% 1-year PFS in treatment-naive RET-mutant MTC patients.
Pralsetinib
Action: targeted therapy Ontology label: Targeted Therapy NCIT:C93352
Agent: pralsetinib ↗
Selective RET inhibitor approved for RET-mutant MTC. The ARROW trial demonstrated 71% response rate in treatment-naive and 60% in previously treated RET-mutant MTC patients.
Show evidence (1 reference)
PMID:34118198 SUPPORT
"thyroid cancer and 33 (60%) of 55 (95% CI 46-73) in patients who had previously"
The ARROW trial demonstrated pralsetinib efficacy with 71% ORR in treatment-naive and 60% in previously treated RET-mutant MTC patients.
Vandetanib
Action: targeted therapy Ontology label: Targeted Therapy NCIT:C93352
Agent: vandetanib ↗
Multi-kinase inhibitor targeting RET, VEGFR, and EGFR approved for advanced MTC. The phase III trial demonstrated significant PFS prolongation versus placebo.
Show evidence (1 reference)
PMID:22025146 SUPPORT
"Vandetanib demonstrated therapeutic efficacy in a phase III trial of"
Phase III trial demonstrated vandetanib has significant therapeutic efficacy in advanced MTC patients.
Cabozantinib
Action: targeted therapy Ontology label: Targeted Therapy NCIT:C93352
Agent: cabozantinib ↗
Multi-kinase inhibitor targeting MET, VEGFR2, and RET approved for progressive metastatic MTC. The EXAM trial demonstrated significant PFS improvement versus placebo.
Show evidence (1 reference)
PMID:24002501 SUPPORT
"The estimated median PFS was 11.2 months for cabozantinib versus 4.0"
The EXAM trial demonstrated cabozantinib significantly improves PFS in progressive metastatic MTC with median 11.2 vs 4.0 months.
🔬

Biochemical Markers

3
Serum Calcitonin
Show evidence (1 reference)
PMID:26494386 SUPPORT
"CTN concentrations in patients with thyroid nodules can lead to an earlier"
Confirms serum calcitonin measurement as superior to imaging alone for early MTC diagnosis.
Serum CEA
Ectopic ACTH-dependent cortisol excess (Increased)
Context: Rare paraneoplastic Cushing syndrome in metastatic MTC
Show evidence (1 reference)
PMID:31885947 SUPPORT Human Clinical
"yielding ACTH dependent Cushing's Syndrome leading to abnormal clinical"
Documents the rare ectopic ACTH/Cushing presentation as a biochemical paraneoplastic manifestation of metastatic MTC.
{ }

Source YAML

click to show 
name: Medullary Thyroid Carcinoma
creation_date: '2026-01-26T02:55:13Z'
updated_date: '2026-05-03T00:00:00Z'
description: Medullary thyroid carcinoma (MTC) is a neuroendocrine malignancy arising from the parafollicular C-cells of the thyroid gland. Approximately 25% of cases are hereditary, caused by germline RET proto-oncogene mutations in MEN2A, MEN2B, or familial MTC syndromes. Sporadic MTC frequently harbors somatic RET mutations, while RET-wild-type tumors can be driven by RAS-family alterations. MTC secretes calcitonin and carcinoembryonic antigen (CEA), providing useful biomarkers. The identification of RET as the driver oncogene led to development of selective RET inhibitors like selpercatinib and pralsetinib.
categories:
- Endocrine Cancer
- Neuroendocrine Tumor
- Hereditary Cancer Syndrome
parents:
- thyroid carcinoma
has_subtypes:
- name: Hereditary MTC (MEN2A)
  description: Associated with MEN2A syndrome caused by germline RET mutations in the extracellular cysteine-rich domain. Patients develop MTC, pheochromocytoma, and primary hyperparathyroidism. Prophylactic thyroidectomy is recommended.
- name: Hereditary MTC (MEN2B)
  description: Associated with MEN2B syndrome caused by germline RET M918T mutation in the kinase domain. Most aggressive form with mucosal neuromas, marfanoid habitus, and very early MTC onset. Pheochromocytoma also occurs.
- name: Sporadic MTC
  description: Approximately 75% of MTC cases are sporadic without germline RET mutations. Somatic RET mutations occur in 40-50% of sporadic cases, and RAS-family mutations are important alternative drivers in RET-wild-type sporadic MTC. Generally presents later than hereditary forms.
pathophysiology:
- name: RET Proto-Oncogene Activation
  description: Activating mutations in the RET receptor tyrosine kinase lead to constitutive kinase activity without ligand binding. This drives downstream signaling through RAS-MAPK and PI3K-AKT pathways, promoting C-cell proliferation and survival.
  cell_types:
  - preferred_term: parafollicular cell
    term:
      id: CL:0000570
      label: parafollicular cell
  biological_processes:
  - preferred_term: RET receptor tyrosine kinase signaling
    modifier: INCREASED
    term:
      id: GO:0007169
      label: cell surface receptor protein tyrosine kinase signaling pathway
  gene_products:
  - preferred_term: RET receptor tyrosine kinase
    term:
      id: NCIT:C18539
      label: Proto-Oncogene Tyrosine-Protein Kinase Receptor Ret
  locations:
  - preferred_term: thyroid gland
    term:
      id: UBERON:0002046
      label: thyroid gland
  evidence:
  - reference: PMID:15355445
    reference_title: Medullary thyroid carcinoma.
    supports: SUPPORT
    snippet: hereditary should be determined by a direct analysis of the RET proto-oncogene
    explanation: Review confirms RET proto-oncogene analysis is central to MTC characterization, supporting the role of RET activation in pathogenesis.
  - reference: PMID:34292174
    reference_title: Medullary thyroid carcinoma.
    supports: SUPPORT
    snippet: understanding of some of the driver mutations in MTC allows for therapeutics
    explanation: Recent review confirms that driver mutations (primarily RET) are central to MTC pathogenesis and therapeutic targeting.
  downstream:
  - target: RAS-MAPK Pathway Activation
    description: RET phosphorylation activates RAS-RAF-MEK-ERK cascade driving proliferation
  - target: PI3K-AKT Pathway Activation
    description: RET phosphorylation recruits PI3K leading to AKT-mediated survival
- name: RAS Mutation-Driven Proliferation
  description: Somatic RAS-family mutations provide an alternative oncogenic driver in RET-wild-type sporadic MTC. Activating HRAS, KRAS, or NRAS lesions converge on MAPK and PI3K-AKT signaling to sustain C-cell proliferation and survival.
  subtypes:
  - Sporadic MTC
  genes:
  - preferred_term: HRAS
    term:
      id: hgnc:5173
      label: HRAS
  - preferred_term: KRAS
    term:
      id: hgnc:6407
      label: KRAS
  - preferred_term: NRAS
    term:
      id: hgnc:7989
      label: NRAS
  biological_processes:
  - preferred_term: MAPK cascade
    modifier: INCREASED
    term:
      id: GO:0000165
      label: MAPK cascade
  - preferred_term: phosphatidylinositol 3-kinase signaling
    modifier: INCREASED
    term:
      id: GO:0043491
      label: phosphatidylinositol 3-kinase/protein kinase B signal transduction
  evidence:
  - reference: PMID:21325462
    reference_title: High prevalence of RAS mutations in RET-negative sporadic medullary thyroid carcinomas.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: 68.0% (17 of 25) of the RET-negative MTC and in only 2.5% of the RET-positive
    explanation: Sequencing of sporadic MTC demonstrates that RAS mutations are enriched in RET-negative tumors, supporting a distinct RAS-driven pathophysiology node.
  downstream:
  - target: RAS-MAPK Pathway Activation
    description: Activating RAS mutations directly feed the MAPK cascade.
  - target: PI3K-AKT Pathway Activation
    description: RAS signaling can also engage PI3K-AKT survival signaling.
- name: RAS-MAPK Pathway Activation
  description: RET activation or activating RAS-family mutations stimulate the RAS-RAF-MEK-ERK signaling cascade, driving uncontrolled C-cell proliferation. This pathway is a major effector of RET- and RAS-mediated transformation in MTC.
  biological_processes:
  - preferred_term: MAPK cascade
    modifier: INCREASED
    term:
      id: GO:0000165
      label: MAPK cascade
- name: PI3K-AKT Pathway Activation
  description: RET activation recruits PI3K and activates the PI3K-AKT-mTOR signaling cascade, promoting C-cell survival and resistance to apoptosis. This cooperates with MAPK signaling to drive MTC tumorigenesis.
  biological_processes:
  - preferred_term: phosphatidylinositol 3-kinase signaling
    modifier: INCREASED
    term:
      id: GO:0043491
      label: phosphatidylinositol 3-kinase/protein kinase B signal transduction
histopathology:
- name: Medullary Thyroid Carcinoma
  finding_term:
    preferred_term: Thyroid Gland Medullary Carcinoma
    term:
      id: NCIT:C3879
      label: Thyroid Gland Medullary Carcinoma
  frequency: VERY_FREQUENT
  description: Medullary thyroid carcinoma originates from parafollicular C cells.
  evidence:
  - reference: PMID:15355445
    reference_title: Medullary thyroid carcinoma.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: produce calcitonin (CT), and accounts for 5-10% of all thyroid cancers
    explanation: Review abstract directly identifies parafollicular/C-cell origin for standard MTC.
phenotypes:
- category: Endocrine
  name: Thyroid Nodule
  frequency: VERY_FREQUENT
  diagnostic: true
  description: MTC typically presents as a firm, painless thyroid nodule. In hereditary cases, bilateral or multifocal disease may be present at diagnosis.
  phenotype_term:
    preferred_term: Thyroid carcinoma
    term:
      id: HP:0002890
      label: Thyroid carcinoma
  evidence:
  - reference: PMID:34292174
    reference_title: Medullary thyroid carcinoma.
    supports: SUPPORT
    snippet: of thyroid nodules has improved the diagnostic accuracy of MTC
    explanation: Confirms that thyroid nodules are the primary clinical presentation of MTC, assessed via cytology.
- category: Constitutional
  name: Diarrhea
  frequency: FREQUENT
  description: Secretory diarrhea occurs in advanced MTC due to tumor secretion of vasoactive substances including calcitonin and prostaglandins.
  phenotype_term:
    preferred_term: Diarrhea
    term:
      id: HP:0002014
      label: Diarrhea
  evidence:
  - reference: DOI:10.1159/000508850
    reference_title: 'Diarrhea as an Initial Presentation in Patients with Medullary Thyroid Cancer: Delaying the Diagnosis'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Tumoral secretion of various molecular factors, such as calcitonin (Ct), can cause diarrhea in patients with medullary thyroid cancer (MTC).
    explanation: Case-series abstract directly attributes diarrhea to tumor-secreted factors in MTC, replacing the prior indirect placebo-arm adverse-event evidence.
- category: Constitutional
  name: Flushing
  frequency: OCCASIONAL
  description: Facial flushing can occur as a hormone-mediated systemic manifestation of MTC, particularly in advanced disease.
  phenotype_term:
    preferred_term: Flushing
    term:
      id: HP:0031284
      label: Flushing
  evidence:
  - reference: PMID:31885947
    reference_title: Sporadic Medullary Thyroid Carcinoma with Paraneoplastic Cushing Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: causing systemic manifestation in the form of flushing, diarrhea, and
    explanation: Case-report abstract directly lists flushing as a systemic manifestation of MTC hormone secretion.
- category: Systemic
  name: Lymph Node Metastasis
  frequency: FREQUENT
  description: Cervical lymph node involvement is common at diagnosis. The extent of nodal disease affects prognosis and surgical planning.
  phenotype_term:
    preferred_term: Lymphadenopathy
    term:
      id: HP:0002716
      label: Lymphadenopathy
- category: Endocrine
  name: Elevated Serum Calcitonin
  frequency: VERY_FREQUENT
  diagnostic: true
  description: Calcitonin is the primary tumor marker for MTC. Elevated basal serum calcitonin concentrations higher than 60-100 pg/mL are highly indicative for MTC diagnosis.
  phenotype_term:
    preferred_term: Elevated circulating calcitonin concentration
    term:
      id: HP:0003528
      label: Elevated circulating calcitonin concentration
  evidence:
  - reference: PMID:26494386
    reference_title: Calcitonin as Biomarker for the Medullary Thyroid Carcinoma.
    supports: SUPPORT
    snippet: pg/mL are highly indicative for the diagnosis MTC
    explanation: Confirms elevated calcitonin as a highly specific diagnostic marker for MTC.
  - reference: PMID:15355445
    reference_title: Medullary thyroid carcinoma.
    supports: SUPPORT
    snippet: produce calcitonin (CT), and accounts for 5-10% of all thyroid cancers
    explanation: Confirms that MTC arises from calcitonin-producing C cells, explaining the characteristic elevated calcitonin levels.
- category: Endocrine
  name: Pheochromocytoma
  frequency: FREQUENT
  subtypes:
  - Hereditary MTC (MEN2A)
  - Hereditary MTC (MEN2B)
  description: Pheochromocytoma occurs in approximately 50% of MEN2A and MEN2B patients and must be screened for before thyroidectomy.
  phenotype_term:
    preferred_term: Pheochromocytoma
    term:
      id: HP:0002666
      label: Pheochromocytoma
  evidence:
  - reference: PMID:33812987
    reference_title: 'Multiple endocrine neoplasia type 2: A review.'
    supports: SUPPORT
    snippet: carcinoma (MTC), phaeochromocytoma, primary hyperparathyroidism, cutaneous
    explanation: Confirms pheochromocytoma as a key feature of both MEN2A and MEN2B syndromes.
  - reference: PMID:15355445
    reference_title: Medullary thyroid carcinoma.
    supports: SUPPORT
    snippet: disease extent should be evaluated, phaeochromocytoma and
    explanation: Review lists pheochromocytoma among the clinical implications to address after MTC diagnosis.
- category: Endocrine
  name: Primary Hyperparathyroidism
  frequency: OCCASIONAL
  subtype: Hereditary MTC (MEN2A)
  description: Primary hyperparathyroidism occurs in MEN2A patients and is caused by parathyroid hyperplasia. It is not a feature of MEN2B.
  phenotype_term:
    preferred_term: Hyperparathyroidism
    term:
      id: HP:0000843
      label: Hyperparathyroidism
  evidence:
  - reference: PMID:33812987
    reference_title: 'Multiple endocrine neoplasia type 2: A review.'
    supports: SUPPORT
    snippet: carcinoma (MTC), phaeochromocytoma, primary hyperparathyroidism, cutaneous
    explanation: Confirms primary hyperparathyroidism as a component of MEN2A syndrome.
biochemical:
- name: Serum Calcitonin
  biomarker_term:
    preferred_term: calcitonin
    term:
      id: NCIT:C2281
      label: Calcitonin
  notes: Calcitonin is the primary tumor marker for MTC. Elevated levels indicate disease presence, and post-operative normalization suggests complete resection. Rising levels after treatment suggest recurrence or residual disease.
  evidence:
  - reference: PMID:26494386
    reference_title: Calcitonin as Biomarker for the Medullary Thyroid Carcinoma.
    supports: SUPPORT
    snippet: CTN concentrations in patients with thyroid nodules can lead to an earlier
    explanation: Confirms serum calcitonin measurement as superior to imaging alone for early MTC diagnosis.
- name: Serum CEA
  biomarker_term:
    preferred_term: carcinoembryonic antigen
    term:
      id: NCIT:C16384
      label: Carcinoembryonic Antigen-Related Cell Adhesion Molecule 5
  notes: Carcinoembryonic antigen (CEA) is elevated in most patients with MTC and correlates with tumor burden. Rapid CEA doubling time suggests aggressive disease.
- name: Ectopic ACTH-dependent cortisol excess
  presence: Increased
  context: Rare paraneoplastic Cushing syndrome in metastatic MTC
  evidence:
  - reference: PMID:31885947
    reference_title: Sporadic Medullary Thyroid Carcinoma with Paraneoplastic Cushing Syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: yielding ACTH dependent Cushing's Syndrome leading to abnormal clinical
    explanation: Documents the rare ectopic ACTH/Cushing presentation as a biochemical paraneoplastic manifestation of metastatic MTC.
genetic:
- name: RET
  association: Germline and Somatic Activating Mutations
  inheritance:
  - name: Autosomal Dominant
  notes: RET mutations are present in virtually all hereditary MTC. Common germline mutations include C634R (MEN2A), M918T (MEN2B), and others. Somatic RET mutations occur in 40-50% of sporadic cases. Genotype-phenotype correlations guide timing of prophylactic thyroidectomy.
  evidence:
  - reference: PMID:32846061
    reference_title: Efficacy of Selpercatinib in RET-Altered Thyroid Cancers.
    supports: SUPPORT
    snippet: RET mutations occur in 70% of medullary thyroid cancers, and RET
    explanation: Confirms high prevalence of RET mutations in MTC (70% including both hereditary and sporadic cases).
  - reference: PMID:33812987
    reference_title: 'Multiple endocrine neoplasia type 2: A review.'
    supports: SUPPORT
    snippet: dominant hereditary cancer syndrome due to germline variants in the REarranged
    explanation: Confirms autosomal dominant inheritance pattern of hereditary MTC through germline RET variants.
- name: HRAS
  gene_term:
    preferred_term: HRAS
    term:
      id: hgnc:5173
      label: HRAS
  association: Somatic activating mutations in RET-negative sporadic MTC
  relationship_type: SOMATIC_DRIVER
  variant_origin: SOMATIC
  subtype: Sporadic MTC
  evidence:
  - reference: PMID:21325462
    reference_title: High prevalence of RAS mutations in RET-negative sporadic medullary thyroid carcinomas.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Somatic H-RAS and K-RAS mutations were detected in 14 of 25 (56.0%) and
    explanation: Supports HRAS as the predominant RAS-family alteration detected in RET-negative sporadic MTC.
  notes: HRAS alterations provide an alternative driver to RET activation in a subset of sporadic MTC.
- name: KRAS
  gene_term:
    preferred_term: KRAS
    term:
      id: hgnc:6407
      label: KRAS
  association: Somatic activating mutations in RET-negative sporadic MTC
  relationship_type: SOMATIC_DRIVER
  variant_origin: SOMATIC
  subtype: Sporadic MTC
  evidence:
  - reference: PMID:21325462
    reference_title: High prevalence of RAS mutations in RET-negative sporadic medullary thyroid carcinomas.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Somatic H-RAS and K-RAS mutations were detected in 14 of 25 (56.0%) and
    explanation: Supports KRAS as a recurrent RAS-family alteration in RET-negative sporadic MTC.
  notes: KRAS alterations are less common than HRAS in the cited RET-negative sporadic MTC cohort but support the RAS-family driver class.
- name: NRAS
  gene_term:
    preferred_term: NRAS
    term:
      id: hgnc:7989
      label: NRAS
  association: Somatic RAS-family alterations in sporadic MTC
  relationship_type: SOMATIC_DRIVER
  variant_origin: SOMATIC
  subtype: Sporadic MTC
  evidence:
  - reference: DOI:10.3390/cancers15194865
    reference_title: 'Molecular Basis and Natural History of Medullary Thyroid Cancer: It is (Almost) All in the RET'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: other genetic alterations such as RAS family (HRAS, KRAS, NRAS) genetic alterations
    explanation: Recent review includes NRAS within the RAS-family genetic alterations relevant to MTC natural history.
  notes: NRAS is included to represent the full RAS-family alternative-driver set, although HRAS and KRAS are more commonly reported in RET-negative sporadic MTC.
treatments:
- name: Thyroidectomy
  description: Total thyroidectomy with central neck dissection is the primary treatment for MTC. In hereditary cases, prophylactic thyroidectomy is recommended based on genotype, often in early childhood for MEN2B.
  treatment_term:
    preferred_term: surgical procedure
    term:
      id: MAXO:0000004
      label: surgical procedure
- name: Selpercatinib
  description: Highly selective RET inhibitor approved for RET-mutant MTC. Demonstrates remarkable efficacy with durable responses in both treatment-naive and previously treated patients. Generally well-tolerated.
  treatment_term:
    preferred_term: targeted therapy
    term:
      id: NCIT:C93352
      label: Targeted Therapy
    therapeutic_agent:
    - preferred_term: selpercatinib
      term:
        id: NCIT:C134987
        label: Selpercatinib
  evidence:
  - reference: PMID:32846061
    reference_title: Efficacy of Selpercatinib in RET-Altered Thyroid Cancers.
    supports: SUPPORT
    snippet: response was 73% (95% CI, 62 to 82), and 1-year progression-free survival was
    explanation: The LIBRETTO-001 trial demonstrated that selpercatinib achieves 73% response rate and 92% 1-year PFS in treatment-naive RET-mutant MTC patients.
- name: Pralsetinib
  description: Selective RET inhibitor approved for RET-mutant MTC. The ARROW trial demonstrated 71% response rate in treatment-naive and 60% in previously treated RET-mutant MTC patients.
  treatment_term:
    preferred_term: targeted therapy
    term:
      id: NCIT:C93352
      label: Targeted Therapy
    therapeutic_agent:
    - preferred_term: pralsetinib
      term:
        id: NCIT:C132295
        label: Pralsetinib
  evidence:
  - reference: PMID:34118198
    reference_title: 'Pralsetinib for patients with advanced or metastatic RET-altered thyroid cancer (ARROW): a multi-cohort, open-label, registrational, phase 1/2 study.'
    supports: SUPPORT
    snippet: thyroid cancer and 33 (60%) of 55 (95% CI 46-73) in patients who had previously
    explanation: The ARROW trial demonstrated pralsetinib efficacy with 71% ORR in treatment-naive and 60% in previously treated RET-mutant MTC patients.
- name: Vandetanib
  description: Multi-kinase inhibitor targeting RET, VEGFR, and EGFR approved for advanced MTC. The phase III trial demonstrated significant PFS prolongation versus placebo.
  treatment_term:
    preferred_term: targeted therapy
    term:
      id: NCIT:C93352
      label: Targeted Therapy
    therapeutic_agent:
    - preferred_term: vandetanib
      term:
        id: CHEBI:49960
        label: vandetanib
  evidence:
  - reference: PMID:22025146
    reference_title: 'Vandetanib in patients with locally advanced or metastatic medullary thyroid cancer: a randomized, double-blind phase III trial.'
    supports: SUPPORT
    snippet: Vandetanib demonstrated therapeutic efficacy in a phase III trial of
    explanation: Phase III trial demonstrated vandetanib has significant therapeutic efficacy in advanced MTC patients.
- name: Cabozantinib
  description: Multi-kinase inhibitor targeting MET, VEGFR2, and RET approved for progressive metastatic MTC. The EXAM trial demonstrated significant PFS improvement versus placebo.
  treatment_term:
    preferred_term: targeted therapy
    term:
      id: NCIT:C93352
      label: Targeted Therapy
    therapeutic_agent:
    - preferred_term: cabozantinib
      term:
        id: CHEBI:72317
        label: cabozantinib
  evidence:
  - reference: PMID:24002501
    reference_title: Cabozantinib in progressive medullary thyroid cancer.
    supports: SUPPORT
    snippet: The estimated median PFS was 11.2 months for cabozantinib versus 4.0
    explanation: The EXAM trial demonstrated cabozantinib significantly improves PFS in progressive metastatic MTC with median 11.2 vs 4.0 months.
disease_term:
  preferred_term: medullary thyroid carcinoma
  term:
    id: MONDO:0015277
    label: medullary thyroid gland carcinoma
classifications:
  icdo_morphology:
    classification_value: Carcinoma
  harrisons_chapter:
  - classification_value: cancer
  - classification_value: solid tumor
references:
- reference: DOI:10.1002/onco.13977
  title: Patient-Reported Outcomes with Selpercatinib Treatment Among Patients with <i>RET</i>-Mutant Medullary Thyroid Cancer in the Phase I/II LIBRETTO-001 Trial
  findings: []
- reference: DOI:10.1007/s11864-023-01145-5
  title: The Evolving Treatment Landscape of Medullary Thyroid Cancer
  findings: []
- reference: DOI:10.1007/s12022-021-09664-3
  title: 'Genomics and Epigenomics of Medullary Thyroid Carcinoma: From Sporadic Disease to Familial Manifestations'
  findings: []
- reference: DOI:10.1056/nejmoa2005651
  title: Efficacy of Selpercatinib in <i>RET</i> -Altered Thyroid Cancers
  findings: []
- reference: DOI:10.1186/s12964-024-01837-x
  title: Molecular genetics, therapeutics and RET inhibitor resistance for medullary thyroid carcinoma and future perspectives
  findings: []
- reference: DOI:10.1200/jco.23.02503
  title: 'Durability of Response With Selpercatinib in Patients With <i>RET</i>-Activated Thyroid Cancer: Long-Term Safety and Efficacy From LIBRETTO-001'
  findings: []
- reference: DOI:10.1210/endrev/bnad013
  title: 'Medullary Thyroid Cancer: Updates and Challenges'
  findings: []
- reference: DOI:10.3390/cancers15194865
  title: 'Molecular Basis and Natural History of Medullary Thyroid Cancer: It is (Almost) All in the RET'
  findings: []
📚

References & Deep Research

References

8
DOI:10.1002/onco.13977
Patient-Reported Outcomes with Selpercatinib Treatment Among Patients with <i>RET</i>-Mutant Medullary Thyroid Cancer in the Phase I/II LIBRETTO-001 Trial
No top-level findings curated for this source.
DOI:10.1007/s11864-023-01145-5
The Evolving Treatment Landscape of Medullary Thyroid Cancer
No top-level findings curated for this source.
DOI:10.1007/s12022-021-09664-3
Genomics and Epigenomics of Medullary Thyroid Carcinoma: From Sporadic Disease to Familial Manifestations
No top-level findings curated for this source.
DOI:10.1056/nejmoa2005651
Efficacy of Selpercatinib in <i>RET</i> -Altered Thyroid Cancers
No top-level findings curated for this source.
DOI:10.1186/s12964-024-01837-x
Molecular genetics, therapeutics and RET inhibitor resistance for medullary thyroid carcinoma and future perspectives
No top-level findings curated for this source.
DOI:10.1200/jco.23.02503
Durability of Response With Selpercatinib in Patients With <i>RET</i>-Activated Thyroid Cancer: Long-Term Safety and Efficacy From LIBRETTO-001
No top-level findings curated for this source.
DOI:10.1210/endrev/bnad013
Medullary Thyroid Cancer: Updates and Challenges
No top-level findings curated for this source.
DOI:10.3390/cancers15194865
Molecular Basis and Natural History of Medullary Thyroid Cancer: It is (Almost) All in the RET
No top-level findings curated for this source.

Deep Research

2
Disorder ▸

Disorder

  • Name: Medullary Thyroid Carcinoma
  • Category:
  • Existing deep-research providers: falcon
  • Existing evidence reference count in YAML: 10

Key Pathophysiology Nodes

  • RET Proto-Oncogene Activation
  • RAS-MAPK Pathway Activation
  • PI3K-AKT Pathway Activation
  • Deep research literature mapping

Citation Inventory (for evidence mapping)

  • DOI:10.1002/onco.13977
  • DOI:10.1007/s11864-023-01145-5
  • DOI:10.1007/s12022-021-09664-3
  • DOI:10.1056/nejmoa2005651
  • DOI:10.1186/s12964-024-01837-x
  • DOI:10.1200/jco.23.02503
  • DOI:10.1210/endrev/bnad013
  • DOI:10.3390/cancers15194865
Falcon ▸
Disease Pathophysiology Research Report
Edison Scientific Literature 26 citations 2026-01-24T13:32:05.631432

Disease Pathophysiology Research Report

Target Disease

  • Disease Name: Medullary Thyroid Carcinoma (MTC)
  • MONDO ID:
  • Category: Neuroendocrine carcinoma of the thyroid gland

Pathophysiology Description

Medullary thyroid carcinoma arises from parafollicular C-cells of neural crest origin and characteristically secretes calcitonin and often carcinoembryonic antigen (CEA). Approximately 25% of cases are hereditary due to germline RET mutations (MEN2 syndromes), while ~75% are sporadic with frequent somatic RET mutations; RAS family mutations (HRAS/KRAS/NRAS) are the predominant alternative drivers in RET-wild-type tumors (mutually exclusive with RET) (gild2023medullarythyroidcancer pages 1-2, lagana2023theevolvingtreatment pages 1-3). Constitutive activation of the RET receptor tyrosine kinase engages RAS/MAPK and PI3K/AKT/mTOR signaling, driving proliferation, survival, migration, and altered differentiation; RAS mutations similarly activate these pathways (gild2023medullarythyroidcancer pages 3-4, barletta2021genomicsandepigenomics pages 10-12, lagana2023theevolvingtreatment pages 1-3). Epigenetic dysregulation (DNA methylation changes, overexpression of EZH2 and SMYD3, and miRNA alterations such as miR-375) correlates with aggressive phenotypes and prognosis (sahakian2023molecularbasisand pages 13-15, barletta2021genomicsandepigenomics pages 10-12).

Clinically, MTC exhibits hormone-mediated syndromes: calcitonin (and related peptides) are implicated in diarrhea and flushing; ectopic ACTH secretion can cause Cushing syndrome in a minority of patients. Surgical resection is the only curative option for localized disease; systemic therapy is reserved for progressive/symptomatic metastatic disease, where selective RET inhibitors (selpercatinib, pralsetinib) now provide high response rates and durable control with improved tolerability compared to multikinase inhibitors (MKIs) such as vandetanib and cabozantinib (lagana2023theevolvingtreatment pages 3-5, gild2023medullarythyroidcancer pages 1-2, lagana2023theevolvingtreatment pages 1-3, sahakian2023molecularbasisand pages 15-16).

Key recent expert consensus emphasizes universal germline RET testing for all MTC patients, somatic profiling to guide targeted therapy, and recognition of acquired resistance mechanisms (on-target RET mutations and bypass signaling) that motivate next-generation inhibitors and rational combinations (gild2023medullarythyroidcancer pages 1-2, gild2023medullarythyroidcancer pages 10-10, lagana2023theevolvingtreatment pages 1-3).

Category Entity (ontology / identifier) Role in MTC Pathophysiology Key Evidence (DOI URL, year; citation)
Driver oncogene RET (HGNC:9967) Germline and somatic activating point mutations, indels and fusions → constitutive RTK activity that drives proliferation, survival and migration via downstream RAS/MAPK and PI3K/AKT signaling DOI: https://doi.org/10.1186/s12964-024-01837-x (2024); DOI: https://doi.org/10.3390/cancers15194865 (2023) (zhang2024moleculargeneticstherapeutics pages 5-6, sahakian2023molecularbasisand pages 1-2)
Oncogenes (mutually exclusive with RET) HRAS / KRAS / NRAS (HGNC:5005, 6407, 7771) Frequent drivers in RET-wild-type sporadic MTC; activate MAPK/PI3K pathways; associated with distinct biology and generally less aggressive phenotype vs RET M918T DOI: https://doi.org/10.1007/s12022-021-09664-3 (2021); review summarizing prevalence (2023) (barletta2021genomicsandepigenomics pages 3-4, lagana2023theevolvingtreatment pages 1-3)
Cell type / origin Parafollicular C-cell (CL:0000198) — Thyroid (UBERON:0002046) Neuroendocrine origin; C-cells synthesize and secrete calcitonin and often CEA — used as sensitive tumor biomarkers and mediators of hormone-related symptoms (diarrhea, flushing) DOI: https://doi.org/10.1210/endrev/bnad013 (2023); clinical summaries (2023) (gild2023medullarythyroidcancer pages 1-2, lagana2023theevolvingtreatment pages 1-3)
Secreted biomarkers / chemical entities Calcitonin (UniProt P01258), CEA (protein) Serum calcitonin highly sensitive for disease burden; rising CEA indicates progression/dedifferentiation and paraneoplastic syndromes (diarrhea, flushing, rare ectopic ACTH) Clinical/guideline summaries (2023) (gild2023medullarythyroidcancer pages 1-2, lagana2023theevolvingtreatment pages 1-3)
Signaling pathway (GO) GO:0007169 — transmembrane receptor protein tyrosine kinase signaling Canonical RET signaling node initiating downstream cascades (PLCγ, Src, RAS/MAPK, PI3K/AKT) that mediate proliferation, survival and migration Mechanistic reviews (2023–2024) DOI: https://doi.org/10.1210/endrev/bnad013 (2023), https://doi.org/10.1186/s12964-024-01837-x (2024) (gild2023medullarythyroidcancer pages 3-4, zhang2024moleculargeneticstherapeutics pages 5-6)
Signaling pathway (GO) GO:0000187 — activation of MAPK activity MAPK/ERK cascade is a principal downstream effector of RET and RAS mutations driving proliferation and tumor growth Mechanistic reviews and genomic studies (2021–2023) (barletta2021genomicsandepigenomics pages 3-4, gild2023medullarythyroidcancer pages 3-4)
Signaling pathway (GO) GO:0043491 — protein kinase B (AKT) signaling PI3K→AKT→mTOR axis activated downstream of RET/RAS; implicated in survival, metabolism and therapeutic targeting (mTOR pathway activation in some MTC) Genomic/functional reports (2021, 2023) (barletta2021genomicsandepigenomics pages 10-12, gild2023medullarythyroidcancer pages 3-4)
Epigenetic regulators EZH2 (HGNC:3527), SMYD3 (HGNC:15564); DNA methylation (GO:0006306); miR-375 (miRNA) Overexpression of EZH2/SMYD3 and DNA methylation changes associate with aggressive behavior; miR-375 deregulation linked to prognosis and drug sensitivity Epigenomics reviews and studies DOI: https://doi.org/10.3390/cancers15194865 (2023); https://doi.org/10.1007/s12022-021-09664-3 (2021) (sahakian2023molecularbasisand pages 13-15, barletta2021genomicsandepigenomics pages 10-12)
Tumor microenvironment / immune PSMA expression, low-TMB immune features; investigational CAR-T targeting CEA/calcitonin/RET MTC shows variable immune features; targeted/theranostic approaches (PSMA PET/PRRT, CAR-T) and combined strategies under active investigation Translational/theranostic reviews (2023) DOI: https://doi.org/10.1210/endrev/bnad013 (2023) (gild2023medullarythyroidcancer pages 10-10)
Approved multikinase inhibitors Vandetanib (targets RET, VEGFR, EGFR) — clinical benefit: ZETA trial PFS ~30.5 vs 19.3 mo (placebo); notable off‑target AEs (diarrhea, rash, QT) Multi-target blockade reduces tumor progression but causes dose-limiting off-target toxicity; better responses in RET‑positive cases Summary review with trial metrics DOI: https://doi.org/10.3390/cancers15194865 (2023) (sahakian2023molecularbasisand pages 15-16)
Approved multikinase inhibitor Cabozantinib (targets RET, MET, VEGFR2, others) — EXAM: PFS ~11.2 vs 4.0 mo (placebo); high rates of dose reduction Broad kinase inhibition yields PFS benefit but frequent toxicity and limited OS benefit historically Trial summary and review DOI: https://doi.org/10.3390/cancers15194865 (2023) (sahakian2023molecularbasisand pages 15-16)
Selective RET inhibitors Selpercatinib (LOXO-292) — high ORR (≈69–82% in trials), durable responses and favorable tolerability; Pralsetinib (BLU-667) — ORR ~60–71% Potent on-target RET inhibition with higher ORR/PFS and improved QoL vs MKIs; central to modern management of RET‑mutant MTC Clinical trial reports and long-term updates DOI: https://doi.org/10.1056/NEJMoa2005651 (2020), long-term JCO update DOI: https://doi.org/10.1200/jco.23.02503 (2024); reviews (gild2023medullarythyroidcancer pages 10-10, sahakian2023molecularbasisand pages 15-16)
Resistance mechanisms On-target (gatekeeper V804L/M, solvent-front), off‑target/bypass pathway activation, RTK indels/compound RET mutations Resistance emerges via secondary RET kinase-domain mutations or activation of bypass pathways (e.g., MET/RAS/PI3K) — motivates next‑generation RET inhibitors and combination strategies Resistance-focused reviews DOI: https://doi.org/10.1186/s12964-024-01837-x (2024); translational reviews (2023) (zhang2024moleculargeneticstherapeutics pages 5-6, gild2023medullarythyroidcancer pages 10-10)

Table: Concise reference table mapping key genes, pathways, cell types, epigenetic factors, microenvironment notes, approved therapies and resistance mechanisms in medullary thyroid carcinoma with primary evidence DOI links and recent review citations (2021–2024).

1. Core Pathophysiology

  • Primary mechanisms: Activating RET mutations (germline in MEN2; somatic in many sporadic cases) or, in RET-wild-type tumors, activating RAS mutations, produce constitutive receptor tyrosine kinase or downstream RAS pathway signaling. RET activates PLCγ/PKC, Src-related kinases, RAS/MAPK and PI3K/AKT pathways, driving oncogenic programs (gild2023medullarythyroidcancer pages 3-4, lagana2023theevolvingtreatment pages 1-3). RAS-mutant MTC shows mTOR pathway activation (barletta2021genomicsandepigenomics pages 10-12).
  • Dysregulated pathways: RAS/MAPK (MAPK/ERK) and PI3K/AKT/mTOR; additional RET-linked nodes include PLCγ/PKC and Src (gild2023medullarythyroidcancer pages 3-4, barletta2021genomicsandepigenomics pages 10-12).
  • Affected cellular processes: Cell proliferation, survival/apoptosis resistance, migration/invasion, and neuroendocrine differentiation/secretion (calcitonin/CEA) (gild2023medullarythyroidcancer pages 3-4, gild2023medullarythyroidcancer pages 1-2, lagana2023theevolvingtreatment pages 1-3).

Notable recent synthesis: “RET is… a receptor tyrosine kinase that activates multiple downstream pathways including… PI3K and MAPK; activating mutations… cause constitutive signaling” (Endocrine Reviews 2023) (gild2023medullarythyroidcancer pages 3-4). A 2024 review underscores RET as “the central initiating driver in hereditary and many sporadic MTCs,” with detailed mechanistic activation models and clinical-genetic correlations (Cell Communication and Signaling, Sep 2024) (zhang2024moleculargeneticstherapeutics pages 5-6).

2. Key Molecular Players

  • Genes/Proteins (HGNC symbols):
  • RET (proto-oncogene receptor tyrosine kinase): germline (MEN2A/B, FMTC) and somatic mutations (e.g., M918T; gatekeeper V804L/M; indels). RET mutations associate with higher odds of nodal and distant metastasis, advanced stage, recurrence, and mortality; exon 15–16 mutations (e.g., M918T) confer worst outcomes (barletta2021genomicsandepigenomics pages 3-4).
  • RAS family: HRAS, KRAS, NRAS; frequent in RET-wild-type sporadic MTC and generally less aggressive than RET M918T–mutant disease (gild2023medullarythyroidcancer pages 3-4, barletta2021genomicsandepigenomics pages 3-4).
  • Epigenetic regulators: EZH2, SMYD3; overexpressed in aggressive tumors (barletta2021genomicsandepigenomics pages 10-12). miR-375 is a negative prognostic marker; miR-153-3p acts as a RET-regulated tumor suppressor (gild2023medullarythyroidcancer pages 10-10, barletta2021genomicsandepigenomics pages 10-12).
  • Chemical Entities (selected): calcitonin (biomarker and symptom mediator), CEA (biomarker); drugs: vandetanib, cabozantinib (MKIs), selpercatinib, pralsetinib (selective RET inhibitors) (lagana2023theevolvingtreatment pages 3-5, lagana2023theevolvingtreatment pages 1-3, sahakian2023molecularbasisand pages 15-16).
  • Cell Types (CL terms): Parafollicular C-cells (CL:0000198) (gild2023medullarythyroidcancer pages 1-2).
  • Anatomical Locations (UBERON terms): Thyroid gland (UBERON:0002046) and regional/distant metastatic sites (cervical nodes, liver, lung, bone) (gild2023medullarythyroidcancer pages 1-2, lagana2023theevolvingtreatment pages 1-3).

Representative data points: “Somatic RET alterations occur in around 60% of sporadic MTC, with many of the remainder driven by RAS mutations… RAS-mutated tumors are described as less aggressive than tumors with RET p.Met918Thr” (Endocrine Reviews 2023) (gild2023medullarythyroidcancer pages 3-4).

3. Biological Processes (GO annotations)

  • Transmembrane receptor protein tyrosine kinase signaling (GO:0007169) via RET (gild2023medullarythyroidcancer pages 3-4, lagana2023theevolvingtreatment pages 1-3).
  • Activation of MAPK activity (GO:0000187) downstream of RET/RAS (gild2023medullarythyroidcancer pages 3-4, barletta2021genomicsandepigenomics pages 10-12, lagana2023theevolvingtreatment pages 1-3).
  • Protein kinase B (AKT) signaling (GO:0043491) and mTOR pathway activation (barletta2021genomicsandepigenomics pages 10-12).
  • DNA methylation (GO:0006306) changes associated with prognosis; chromatin modification via EZH2/SMYD3 (sahakian2023molecularbasisand pages 13-15, barletta2021genomicsandepigenomics pages 10-12).
  • Neuroendocrine hormone secretion processes (calcitonin/CEA) contributing to systemic symptoms (gild2023medullarythyroidcancer pages 1-2, lagana2023theevolvingtreatment pages 1-3).

Directly supported elements include the RET-driven activation of MAPK and PI3K cascades (Endocrine Reviews 2023) and epigenetic alterations linked to aggressiveness (Endocrine Pathology 2021; Cancers 2023) (gild2023medullarythyroidcancer pages 3-4, barletta2021genomicsandepigenomics pages 10-12, sahakian2023molecularbasisand pages 13-15).

4. Cellular Components

  • Plasma membrane: RET receptor localization and activation (gild2023medullarythyroidcancer pages 3-4).
  • Cytoplasm: MAPK/ERK and PI3K/AKT/mTOR signaling cascades (barletta2021genomicsandepigenomics pages 10-12).
  • Nucleus/chromatin: epigenetic regulation (EZH2/SMYD3), transcriptional responses; miRNA-mediated post-transcriptional control (barletta2021genomicsandepigenomics pages 10-12, gild2023medullarythyroidcancer pages 10-10).
  • Extracellular space: calcitonin/CEA secretion and biomarker monitoring (gild2023medullarythyroidcancer pages 1-2, lagana2023theevolvingtreatment pages 1-3).

5. Disease Progression

  • Sequence of events: In hereditary disease, diffuse C-cell hyperplasia (premalignant) can progress to microcarcinoma, invasive carcinoma, nodal metastases, and distant metastases. Somatic RET (often M918T) or RAS mutations drive sporadic tumorigenesis, with RET mutations correlating strongly with advanced stage and metastasis (barletta2021genomicsandepigenomics pages 10-12, lagana2023theevolvingtreatment pages 1-3). “Cervical nodal involvement at initial surgery carries a poor cure rate (~10%)” (Curr Treat Options Oncol 2023) (lagana2023theevolvingtreatment pages 3-5).
  • Staging phases: localized intrathyroidal disease, regional nodal spread, and distant metastasis (liver, lung, bone) are typical trajectories; many metastatic cases exhibit indolent courses, necessitating careful selection for systemic therapy (lagana2023theevolvingtreatment pages 3-5, lagana2023theevolvingtreatment pages 1-3).

6. Phenotypic Manifestations

  • Key clinical phenotypes (HP terms):
  • Chronic diarrhea (HP:0002014) and flushing (HP term for facial flushing), often linked to calcitonin and neuropeptides (lagana2023theevolvingtreatment pages 3-5, lagana2023theevolvingtreatment pages 1-3).
  • Ectopic ACTH secretion causing Cushing syndrome (HP:0003119) (lagana2023theevolvingtreatment pages 3-5).
  • Thyroid nodule and cervical lymphadenopathy; elevated serum calcitonin and CEA (biochemical phenotypes) (gild2023medullarythyroidcancer pages 1-2, lagana2023theevolvingtreatment pages 1-3).

“Systemic symptoms arise from hormonal secretion (calcitonin and calcitonin gene-related peptide) causing diarrhea and flushing; occasional ectopic ACTH/Cushing’s is described” (Curr Treat Options Oncol 2023) (lagana2023theevolvingtreatment pages 3-5).

Expert Opinions and Authoritative Guidance

  • Universal germline RET testing is recommended for all MTC patients to identify MEN2 and guide prophylactic and therapeutic decisions (Endocrine Reviews 2023) (gild2023medullarythyroidcancer pages 1-2).
  • Somatic profiling (RET vs RAS) informs selection of selective RET inhibitors vs alternative strategies; selective RET inhibitors are preferred for RET-mutant disease due to higher efficacy and tolerability compared with MKIs (lagana2023theevolvingtreatment pages 1-3).
  • Surveillance and local therapies are appropriate for indolent metastatic disease; systemic therapy is noncurative and reserved for symptomatic or RECIST-progressive disease (lagana2023theevolvingtreatment pages 3-5).

Relevant Statistics and Data (recent)

  • Genetics/epidemiology: Sporadic ~75% vs hereditary ~25% of MTC; somatic RET alterations ~60% of sporadic tumors; RET and RAS together account for ~90% of MTCs (Endocrine Reviews 2023; Curr Treat Options Oncol 2023) (gild2023medullarythyroidcancer pages 3-4, lagana2023theevolvingtreatment pages 1-3).
  • Prognostic impact: Meta-analysis—RET mutations associate with higher odds of lymph node metastasis (OR 3.61), distant metastasis (OR 2.85), advanced stage (OR 3.25), recurrence (OR 3.01), mortality (OR 2.43); exons 15–16 (including M918T) confer worst outcomes (Endocrine Pathology 2021) (barletta2021genomicsandepigenomics pages 3-4).
  • MKIs: Vandetanib (ZETA): PFS 30.5 vs 19.3 months (placebo); cabozantinib (EXAM): PFS 11.2 vs 4.0 months; notable off‑target toxicities and frequent dose modifications (Cancers 2023) (sahakian2023molecularbasisand pages 15-16).
  • Selective RET inhibitors:
  • Selpercatinib (NEJM 2020; LIBRETTO-001): ORR 69% in previously treated RET-mutant MTC and 73% in MKI‑naïve; 1‑year PFS 82% and 92%, respectively; grade ≥3 AEs included hypertension (21%), elevated ALT (11%), AST (9%), hyponatremia (8%), diarrhea (6%); 2% discontinued for drug-related AEs (published Aug 2020; https://doi.org/10.1056/NEJMoa2005651) (barletta2021genomicsandepigenomics pages 6-7).
  • Long-term update (JCO 2024): ORR 82.5% among MKI‑naïve MTC; median PFS not reached (MKI‑naïve) and 41.4 months (pretreated); 3‑year PFS 75.2% (MKI‑naïve) (published Sep 2024; https://doi.org/10.1200/JCO.23.02503) (gild2023medullarythyroidcancer pages 10-10).
  • Patient-reported outcomes: clinically meaningful improvement in diarrhea in 43.5% overall (LIBRETTO‑001 PROs) (The Oncologist 2022; https://doi.org/10.1002/onco.13977) (lagana2023theevolvingtreatment pages 3-5).
  • Pralsetinib (ARROW): ORR 60% (pretreated) and 71% (treatment‑naïve); disease control rates 93–100% (Cancers 2023) (sahakian2023molecularbasisand pages 15-16).

Therapy Mechanisms Linked to Biology, and Resistance

  • MKIs (vandetanib, cabozantinib) inhibit RET and multiple other kinases (VEGFR, EGFR, MET), providing PFS benefit but with substantial off‑target toxicity; responses are higher in RET‑positive tumors (sahakian2023molecularbasisand pages 15-16).
  • Selective RET inhibitors (selpercatinib, pralsetinib) provide potent on-target RET blockade with high response rates, prolonged PFS, and improved tolerability and HRQoL (barletta2021genomicsandepigenomics pages 6-7, gild2023medullarythyroidcancer pages 10-10, lagana2023theevolvingtreatment pages 3-5).
  • Resistance mechanisms: on-target RET mutations (gatekeeper V804L/M, solvent-front) and off-target/bypass activation (e.g., MET/RAS/PI3K) are recognized; development of next-generation RET inhibitors and combinations is ongoing (Endocrine Reviews 2023; Cell Communication and Signaling 2024) (gild2023medullarythyroidcancer pages 10-10, zhang2024moleculargeneticstherapeutics pages 5-6).

Structured Annotations

  • Genes/Proteins (HGNC): RET; HRAS; KRAS; NRAS; EZH2; SMYD3; biomarkers calcitonin, CEA (gild2023medullarythyroidcancer pages 3-4, barletta2021genomicsandepigenomics pages 10-12, lagana2023theevolvingtreatment pages 1-3).
  • GO Biological Processes: GO:0007169 (RTK signaling); GO:0000187 (activation of MAPK activity); GO:0043491 (protein kinase B signaling); GO:0006306 (DNA methylation) (gild2023medullarythyroidcancer pages 3-4, barletta2021genomicsandepigenomics pages 10-12).
  • Cell Types (CL): Parafollicular C-cell (CL:0000198) (gild2023medullarythyroidcancer pages 1-2).
  • Anatomical Locations (UBERON): Thyroid gland (UBERON:0002046); common metastatic sites (regional lymph nodes, liver, lung, bone) (gild2023medullarythyroidcancer pages 1-2, lagana2023theevolvingtreatment pages 1-3).
  • Phenotypes (HP): Diarrhea (HP:0002014), Flushing, Cushing syndrome (HP:0003119) (lagana2023theevolvingtreatment pages 3-5).
  • Chemical Entities (CHEBI examples): drugs—vandetanib, cabozantinib, selpercatinib, pralsetinib; hormones—calcitonin (sahakian2023molecularbasisand pages 15-16, barletta2021genomicsandepigenomics pages 6-7, gild2023medullarythyroidcancer pages 10-10).

Evidence Items with URLs and Publication Dates

  • Gild ML et al. Medullary Thyroid Cancer: Updates and Challenges. Endocrine Reviews. May 2023. URL: https://doi.org/10.1210/endrev/bnad013 (gild2023medullarythyroidcancer pages 1-2, gild2023medullarythyroidcancer pages 3-4, gild2023medullarythyroidcancer pages 10-10)
  • Laganà M et al. The Evolving Treatment Landscape of MTC. Current Treatment Options in Oncology. Nov 18, 2023. URL: https://doi.org/10.1007/s11864-023-01145-5 (lagana2023theevolvingtreatment pages 1-3, lagana2023theevolvingtreatment pages 3-5)
  • Sahakian N et al. Molecular Basis and Natural History of MTC. Cancers. Oct 5, 2023. URL: https://doi.org/10.3390/cancers15194865 (sahakian2023molecularbasisand pages 1-2, sahakian2023molecularbasisand pages 13-15, sahakian2023molecularbasisand pages 15-16)
  • Barletta JA et al. Genomics and Epigenomics of MTC. Endocrine Pathology. Jan 2021. URL: https://doi.org/10.1007/s12022-021-09664-3 (barletta2021genomicsandepigenomics pages 10-12, barletta2021genomicsandepigenomics pages 3-4)
  • Wirth LJ et al. Efficacy of Selpercatinib in RET‑Altered Thyroid Cancers. NEJM. Aug 27, 2020. URL: https://doi.org/10.1056/NEJMoa2005651 (barletta2021genomicsandepigenomics pages 6-7)
  • Wirth LJ et al. Durability of Response With Selpercatinib (LIBRETTO‑001). J Clin Oncol. Sep 2024. URL: https://doi.org/10.1200/JCO.23.02503 (gild2023medullarythyroidcancer pages 10-10)
  • Wirth LJ et al. Patient-Reported Outcomes With Selpercatinib (LIBRETTO‑001). The Oncologist. Sep 2022. URL: https://doi.org/10.1002/onco.13977 (lagana2023theevolvingtreatment pages 3-5)

Quoted statements - “RET is… a receptor tyrosine kinase that activates multiple downstream pathways including… PI3K and MAPK; activating mutations… cause constitutive signaling” (Endocrine Reviews 2023) (gild2023medullarythyroidcancer pages 3-4). - “Selpercatinib showed durable efficacy with mainly low-grade toxic effects” with ORR 69–73% and 1‑year PFS 82–92% in RET‑mutant MTC (NEJM 2020) (barletta2021genomicsandepigenomics pages 6-7).

Current Applications and Real-World Implementations

  • Diagnostics: universal germline RET testing; somatic profiling to select targeted therapy; calcitonin/CEA for disease burden and kinetics; 18F‑DOPA PET and 68Ga‑DOTATATE PET for lesion detection (gild2023medullarythyroidcancer pages 1-2).
  • Therapeutics: MKIs (vandetanib, cabozantinib) for unselected progressive disease; selective RET inhibitors (selpercatinib, pralsetinib) for RET‑mutant tumors with superior ORR/PFS and HRQoL; bone metastasis supportive therapy (bisphosphonates/denosumab) (lagana2023theevolvingtreatment pages 3-5, lagana2023theevolvingtreatment pages 1-3, barletta2021genomicsandepigenomics pages 6-7, gild2023medullarythyroidcancer pages 10-10).
  • Emerging strategies: next‑generation RET inhibitors to overcome resistance; immunotherapeutics (e.g., engineered T cells against CEA/calcitonin/RET) and theranostics (PSMA modalities) under investigation (gild2023medullarythyroidcancer pages 10-10).

Expert Opinions and Analysis

Leading reviews emphasize that molecular stratification around RET and RAS status is central to prognosis and therapeutic decision-making, with selective RET inhibitors establishing a new standard for RET‑mutant MTC. However, acquired resistance is increasingly observed, necessitating vigilant monitoring and enrollment in trials of next‑generation inhibitors and combinations, especially where on‑target RET resistance mutations (e.g., V804L/M or solvent‑front changes) or bypass signaling are suspected (gild2023medullarythyroidcancer pages 1-2, gild2023medullarythyroidcancer pages 10-10, lagana2023theevolvingtreatment pages 1-3, zhang2024moleculargeneticstherapeutics pages 5-6).

Plan status update

Scope defined; recent literature and trial data collated (2020–2024, prioritized 2023–2024); evidence extracted for mechanisms, applications, and statistics; ontology mappings provided; summary artifact embedded.

References

  1. (gild2023medullarythyroidcancer pages 1-2): Matti L Gild, Roderick J Clifton-Bligh, Lori J Wirth, and Bruce G Robinson. Medullary thyroid cancer: updates and challenges. Endocrine Reviews, 44:934-946, May 2023. URL: https://doi.org/10.1210/endrev/bnad013, doi:10.1210/endrev/bnad013. This article has 90 citations and is from a domain leading peer-reviewed journal.

  2. (lagana2023theevolvingtreatment pages 1-3): Marta Laganà, Valentina Cremaschi, Andrea Alberti, Danica M. Vodopivec Kuri, Deborah Cosentini, and Alfredo Berruti. The evolving treatment landscape of medullary thyroid cancer. Current Treatment Options in Oncology, 24:1815-1832, Nov 2023. URL: https://doi.org/10.1007/s11864-023-01145-5, doi:10.1007/s11864-023-01145-5. This article has 11 citations and is from a peer-reviewed journal.

  3. (gild2023medullarythyroidcancer pages 3-4): Matti L Gild, Roderick J Clifton-Bligh, Lori J Wirth, and Bruce G Robinson. Medullary thyroid cancer: updates and challenges. Endocrine Reviews, 44:934-946, May 2023. URL: https://doi.org/10.1210/endrev/bnad013, doi:10.1210/endrev/bnad013. This article has 90 citations and is from a domain leading peer-reviewed journal.

  4. (barletta2021genomicsandepigenomics pages 10-12): Justine A. Barletta, Vânia Nosé, and Peter M. Sadow. Genomics and epigenomics of medullary thyroid carcinoma: from sporadic disease to familial manifestations. Endocrine Pathology, 32:35-43, Jan 2021. URL: https://doi.org/10.1007/s12022-021-09664-3, doi:10.1007/s12022-021-09664-3. This article has 64 citations and is from a peer-reviewed journal.

  5. (sahakian2023molecularbasisand pages 13-15): Nicolas Sahakian, Frédéric Castinetti, and Pauline Romanet. Molecular basis and natural history of medullary thyroid cancer: it is (almost) all in the ret. Cancers, 15:4865, Oct 2023. URL: https://doi.org/10.3390/cancers15194865, doi:10.3390/cancers15194865. This article has 22 citations and is from a poor quality or predatory journal.

  6. (lagana2023theevolvingtreatment pages 3-5): Marta Laganà, Valentina Cremaschi, Andrea Alberti, Danica M. Vodopivec Kuri, Deborah Cosentini, and Alfredo Berruti. The evolving treatment landscape of medullary thyroid cancer. Current Treatment Options in Oncology, 24:1815-1832, Nov 2023. URL: https://doi.org/10.1007/s11864-023-01145-5, doi:10.1007/s11864-023-01145-5. This article has 11 citations and is from a peer-reviewed journal.

  7. (sahakian2023molecularbasisand pages 15-16): Nicolas Sahakian, Frédéric Castinetti, and Pauline Romanet. Molecular basis and natural history of medullary thyroid cancer: it is (almost) all in the ret. Cancers, 15:4865, Oct 2023. URL: https://doi.org/10.3390/cancers15194865, doi:10.3390/cancers15194865. This article has 22 citations and is from a poor quality or predatory journal.

  8. (gild2023medullarythyroidcancer pages 10-10): Matti L Gild, Roderick J Clifton-Bligh, Lori J Wirth, and Bruce G Robinson. Medullary thyroid cancer: updates and challenges. Endocrine Reviews, 44:934-946, May 2023. URL: https://doi.org/10.1210/endrev/bnad013, doi:10.1210/endrev/bnad013. This article has 90 citations and is from a domain leading peer-reviewed journal.

  9. (zhang2024moleculargeneticstherapeutics pages 5-6): Ying Zhang, Wei-Hui Zheng, Shi-Hong Zhou, Jia-Lei Gu, Qing Yu, Yi-Zhou Zhu, Yu-Jie Yan, Zhi Zhu, and Jin-Biao Shang. Molecular genetics, therapeutics and ret inhibitor resistance for medullary thyroid carcinoma and future perspectives. Cell Communication and Signaling : CCS, Sep 2024. URL: https://doi.org/10.1186/s12964-024-01837-x, doi:10.1186/s12964-024-01837-x. This article has 16 citations.

  10. (sahakian2023molecularbasisand pages 1-2): Nicolas Sahakian, Frédéric Castinetti, and Pauline Romanet. Molecular basis and natural history of medullary thyroid cancer: it is (almost) all in the ret. Cancers, 15:4865, Oct 2023. URL: https://doi.org/10.3390/cancers15194865, doi:10.3390/cancers15194865. This article has 22 citations and is from a poor quality or predatory journal.

  11. (barletta2021genomicsandepigenomics pages 3-4): Justine A. Barletta, Vânia Nosé, and Peter M. Sadow. Genomics and epigenomics of medullary thyroid carcinoma: from sporadic disease to familial manifestations. Endocrine Pathology, 32:35-43, Jan 2021. URL: https://doi.org/10.1007/s12022-021-09664-3, doi:10.1007/s12022-021-09664-3. This article has 64 citations and is from a peer-reviewed journal.

  12. (barletta2021genomicsandepigenomics pages 6-7): Justine A. Barletta, Vânia Nosé, and Peter M. Sadow. Genomics and epigenomics of medullary thyroid carcinoma: from sporadic disease to familial manifestations. Endocrine Pathology, 32:35-43, Jan 2021. URL: https://doi.org/10.1007/s12022-021-09664-3, doi:10.1007/s12022-021-09664-3. This article has 64 citations and is from a peer-reviewed journal.