Malignant peripheral nerve sheath tumor (MPNST) is an aggressive soft tissue sarcoma of peripheral nerve sheath lineage. The disease is modeled here as a single dismech mechanism-graph unit, with predisposition-context facets (NF1-associated, sporadic, radiation-associated) and histologic facets (epithelioid, malignant triton tumor) represented as subtype annotations rather than separate disease pages. Core conventional MPNST biology converges on NF1/RAS pathway activation, loss of CDKN2A and TP53 tumor-suppressor checkpoints, recurrent PRC2 inactivation with H3K27me3 loss, and extensive copy-number aberrations. Epithelioid MPNST is retained in this entry as a subtype-scoped branch because it has distinct SMARCB1-centered biology but remains within the broader MPNST disease unit.
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name: Malignant Peripheral Nerve Sheath Tumor
creation_date: '2026-04-12T22:30:00Z'
category: Cancer
categories:
- Sarcoma
- Soft Tissue Sarcoma
- Peripheral Nerve Sheath Tumor
- Rare Cancer
parents:
- soft tissue sarcoma
synonyms:
- MPNST
- malignant schwannoma
- neurofibrosarcoma
- neurogenic sarcoma
disease_term:
preferred_term: malignant peripheral nerve sheath tumor
term:
id: MONDO:0017827
label: malignant peripheral nerve sheath tumor
description: >-
Malignant peripheral nerve sheath tumor (MPNST) is an aggressive soft tissue
sarcoma of peripheral nerve sheath lineage. The disease is modeled here as a
single dismech mechanism-graph unit, with predisposition-context facets
(NF1-associated, sporadic, radiation-associated) and histologic facets
(epithelioid, malignant triton tumor) represented as subtype annotations
rather than separate disease pages. Core conventional MPNST biology converges
on NF1/RAS pathway activation, loss of CDKN2A and TP53 tumor-suppressor
checkpoints, recurrent PRC2 inactivation with H3K27me3 loss, and extensive
copy-number aberrations. Epithelioid MPNST is retained in this entry as a
subtype-scoped branch because it has distinct SMARCB1-centered biology but
remains within the broader MPNST disease unit.
definitions:
- name: Pathologic definition of malignant peripheral nerve sheath tumor
definition_type: CASE_DEFINITION
description: >-
MPNST is an uncommon, biologically aggressive soft tissue sarcoma of neural
origin that includes NF1-associated, sporadic, and radiation-associated
disease.
scope: General pathologic and clinical definition of malignant peripheral nerve sheath tumor
evidence:
- reference: PMID:24470531
reference_title: "Malignant peripheral nerve sheath tumors."
supports: SUPPORT
evidence_source: OTHER
snippet: "Malignant peripheral nerve sheath tumors (MPNST) are uncommon, biologically aggressive soft tissue sarcomas of neural origin that pose tremendous challenges to effective therapy."
explanation: This review abstract provides a concise disease-level definition of MPNST as an aggressive neural-origin soft tissue sarcoma.
has_subtypes:
- name: NF1-Associated
display_name: NF1-Associated Malignant Peripheral Nerve Sheath Tumor
classification: predisposition_context
description: >-
Predisposition-context facet for tumors arising in the setting of
neurofibromatosis type 1, typically after malignant transformation of a
pre-existing plexiform neurofibroma.
evidence:
- reference: PMID:24470531
reference_title: "Malignant peripheral nerve sheath tumors."
supports: SUPPORT
evidence_source: OTHER
snippet: "In 50% of cases, they occur in the context of neurofibromatosis type I, characterized by loss of function mutations to the tumor suppressor neurofibromin; the remainder arise sporadically or following radiation therapy."
explanation: This supports NF1-associated MPNST as a major predisposition-context subtype and grounds its relationship to neurofibromin loss.
review_notes: "Flat subtype facet capturing predisposition context rather than a separate dismech disease page, following the cancer-modeling guidance from issue #1198."
- name: Sporadic
display_name: Sporadic Malignant Peripheral Nerve Sheath Tumor
classification: predisposition_context
description: >-
Predisposition-context facet for tumors arising without recognized NF1 or
prior therapeutic radiation.
evidence:
- reference: PMID:24470531
reference_title: "Malignant peripheral nerve sheath tumors."
supports: SUPPORT
evidence_source: OTHER
snippet: "In 50% of cases, they occur in the context of neurofibromatosis type I, characterized by loss of function mutations to the tumor suppressor neurofibromin; the remainder arise sporadically or following radiation therapy."
explanation: This same disease-overview sentence also supports sporadic MPNST as a distinct predisposition-context facet within the parent disease entry.
review_notes: >-
Flat subtype facet capturing predisposition context rather than a separate
disease page.
- name: Radiation-Associated
display_name: Radiation-Associated Malignant Peripheral Nerve Sheath Tumor
classification: predisposition_context
description: >-
Predisposition-context facet for tumors arising after prior radiotherapy.
This group often shares the conventional PRC2-loss/H3K27me3-loss branch of
MPNST biology.
evidence:
- reference: PMID:25240281
reference_title: "PRC2 is recurrently inactivated through EED or SUZ12 loss in malignant peripheral nerve sheath tumors."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Malignant peripheral nerve sheath tumors (MPNSTs) represent a group of highly aggressive soft-tissue sarcomas that may occur sporadically, in association with neurofibromatosis type I (NF1 associated) or after radiotherapy."
explanation: This genomic study explicitly supports radiation-associated MPNST as a recognized clinical-context subtype within the broader disease.
review_notes: >-
Flat subtype facet capturing exposure/predisposition context rather than a
separate disease page.
- name: Epithelioid
display_name: Epithelioid Malignant Peripheral Nerve Sheath Tumor
classification: histological
subtype_term:
preferred_term: epithelioid malignant peripheral nerve sheath tumor
term:
id: MONDO:0004540
label: epithelioid malignant peripheral nerve sheath tumor
description: >-
Histologic facet defined by epithelioid morphology, diffuse S100/SOX10
expression, rare association with NF1, and frequent SMARCB1 loss rather
than the typical conventional PRC2-loss pattern.
evidence:
- reference: PMID:25602794
reference_title: "Epithelioid malignant peripheral nerve sheath tumor: clinicopathologic analysis of 63 cases."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Epithelioid malignant peripheral nerve sheath tumor (EMPNST) is rare and differs from conventional malignant peripheral nerve sheath tumor by showing diffuse S-100 protein positivity, infrequent association with NF1, and occasional origin in a schwannoma."
explanation: This large clinicopathologic series supports epithelioid MPNST as a distinct histologic facet with characteristic diagnostic features.
review_notes: >-
Represented here as a histologic facet of MPNST rather than a separate
dismech page; subtype grounding is for ontology alignment only.
- name: Malignant Triton Tumor
display_name: Malignant Triton Tumor
classification: histological
subtype_term:
preferred_term: malignant triton tumor
term:
id: MONDO:0016757
label: malignant triton tumor
description: >-
Histologic facet of MPNST with heterologous rhabdomyoblastic
differentiation.
evidence:
- reference: PMID:17149968
reference_title: "Malignant peripheral nerve sheath tumor with rhabdomyosarcomatous differentiation (malignant triton tumor)."
supports: SUPPORT
evidence_source: OTHER
snippet: "Malignant peripheral nerve sheath tumor with rhabdomyosarcomatous differentiation is also known as malignant triton tumor."
explanation: This review abstract directly supports malignant triton tumor as a named histologic MPNST subtype.
review_notes: >-
Represented as a histologic facet of the parent MPNST entry rather than a
separate dismech page.
pathophysiology:
- name: NF1 Biallelic Inactivation
description: >-
Conventional MPNST evolution commonly begins with complete loss of NF1 tumor
suppressor function in Schwann-lineage cells, especially in NF1-associated
disease, creating the substrate for additional tumor-suppressor and
epigenetic lesions.
cell_types:
- preferred_term: Schwann cell
term:
id: CL:0002573
label: Schwann cell
genes:
- preferred_term: NF1
term:
id: hgnc:7765
label: NF1
evidence:
- reference: PMID:36598417
reference_title: "Genomic Patterns of Malignant Peripheral Nerve Sheath Tumor (MPNST) Evolution Correlate with Clinical Outcome and Are Detectable in Cell-Free DNA."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Following biallelic inactivation of NF1, loss of CDKN2A or TP53 with or without inactivation of polycomb repressive complex 2 (PRC2) leads to extensive somatic copy-number aberrations (SCNA)."
explanation: This large genomic study explicitly places biallelic NF1 loss upstream of later checkpoint, PRC2, and copy-number events in MPNST evolution.
downstream:
- target: Ras Pathway Hyperactivation
description: Loss of neurofibromin removes a major brake on Ras signaling in Schwann-lineage tumor cells.
evidence:
- reference: PMID:31023785
reference_title: "Malignant Peripheral Nerve Sheath Tumors: From Epigenome to Bedside."
supports: SUPPORT
evidence_source: OTHER
snippet: "Consequently, loss of function mutations in NF1 result in hyperactive Ras signaling, promoting aberrant cellular proliferation."
explanation: This review directly supports the specific NF1-loss to Ras-hyperactivation mechanism represented by this downstream edge.
- name: Ras Pathway Hyperactivation
description: >-
NF1 loss and additional secondary lesions converge on sustained Ras-pathway
signaling, which reinforces malignant growth and cooperates with downstream
cell-cycle and chromatin dysregulation.
cell_types:
- preferred_term: Schwann cell
term:
id: CL:0002573
label: Schwann cell
biological_processes:
- preferred_term: Ras protein signal transduction
modifier: INCREASED
term:
id: GO:0007265
label: Ras protein signal transduction
evidence:
- reference: PMID:29118384
reference_title: "The genomic landscape of malignant peripheral nerve sheath tumors: diverse drivers of Ras pathway activation."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Notably, we also identified frequent Ras pathway activating somatic mutations outside of these previously reported recurrently mutated genes."
explanation: This genomic study supports convergent activation of the Ras pathway beyond NF1 loss alone in MPNST.
downstream:
- target: Cell Cycle Deregulation
description: Persistent Ras signaling contributes to unchecked tumor-cell proliferation.
- name: CDKN2A/B Loss
description: >-
Deletion of CDKN2A/B is an early cooperative event in malignant progression,
weakening cell-cycle restraint before or during transition from atypical
neurofibroma to overt MPNST.
genes:
- preferred_term: CDKN2A
term:
id: hgnc:1787
label: CDKN2A
- preferred_term: CDKN2B
term:
id: hgnc:1788
label: CDKN2B
biological_processes:
- preferred_term: cell cycle checkpoint signaling
modifier: DECREASED
term:
id: GO:0000075
label: cell cycle checkpoint signaling
evidence:
- reference: PMID:30722027
reference_title: "Low mutation burden and frequent loss of CDKN2A/B and SMARCA2, but not PRC2, define premalignant neurofibromatosis type 1-associated atypical neurofibromas."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "The PN-ANF transition is primarily driven by the deletion of CDKN2A/B."
explanation: This genomic progression study supports CDKN2A/B loss as an early checkpoint-disrupting event on the benign-to-malignant path in NF1-associated disease.
- reference: PMID:25240281
reference_title: "PRC2 is recurrently inactivated through EED or SUZ12 loss in malignant peripheral nerve sheath tumors."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Additionally, we identified frequent somatic alterations of CDKN2A (81% of all MPNSTs) and NF1 (72% of non-NF1-associated MPNSTs), both of which significantly co-occur with PRC2 alterations."
explanation: This large genomic cohort confirms that CDKN2A loss is a recurrent event in established MPNSTs across etiologic contexts.
downstream:
- target: Cell Cycle Deregulation
description: Loss of CDKN2A/B-mediated checkpoint control permits unchecked cell-cycle entry.
- name: TP53 Pathway Loss
description: >-
TP53 disruption removes an additional tumor-suppressive barrier, promoting
malignant progression and large-scale genomic instability.
genes:
- preferred_term: TP53
term:
id: hgnc:11998
label: TP53
biological_processes:
- preferred_term: DNA damage response
modifier: DECREASED
term:
id: GO:0006974
label: DNA damage response
evidence:
- reference: PMID:29118384
reference_title: "The genomic landscape of malignant peripheral nerve sheath tumors: diverse drivers of Ras pathway activation."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "We report recurrent mutations in NF1, SUZ12, EED, TP53 and CDKN2A in our study cohort."
explanation: This genomic study confirms TP53 as a recurrent tumor-suppressor lesion in MPNST.
downstream:
- target: Copy-Number Driven Genomic Instability
description: Loss of TP53-mediated genome surveillance facilitates extensive somatic copy-number aberrations.
evidence:
- reference: PMID:36598417
reference_title: "Genomic Patterns of Malignant Peripheral Nerve Sheath Tumor (MPNST) Evolution Correlate with Clinical Outcome and Are Detectable in Cell-Free DNA."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Following biallelic inactivation of NF1, loss of CDKN2A or TP53 with or without inactivation of polycomb repressive complex 2 (PRC2) leads to extensive somatic copy-number aberrations (SCNA)."
explanation: This supports TP53 loss as one of the major upstream lesions associated with widespread copy-number instability in MPNST.
- name: PRC2 Core Complex Inactivation
description: >-
Conventional MPNSTs recurrently inactivate the PRC2 core components SUZ12 or
EED, creating a major epigenetic branch of disease evolution across NF1,
sporadic, and radiation-associated settings.
genes:
- preferred_term: SUZ12
term:
id: hgnc:17101
label: SUZ12
- preferred_term: EED
term:
id: hgnc:3188
label: EED
biological_processes:
- preferred_term: chromatin organization
modifier: ABNORMAL
term:
id: GO:0006325
label: chromatin organization
evidence:
- reference: PMID:25240281
reference_title: "PRC2 is recurrently inactivated through EED or SUZ12 loss in malignant peripheral nerve sheath tumors."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Using comprehensive genomic approaches, we identified loss-of-function somatic alterations of the Polycomb repressive complex 2 (PRC2) components (EED or SUZ12) in 92% of sporadic, 70% of NF1-associated and 90% of radiotherapy-associated MPNSTs."
explanation: This directly supports recurrent SUZ12/EED loss as a cross-context epigenetic driver in conventional MPNST.
- reference: PMID:32642732
reference_title: "Genetics of human malignant peripheral nerve sheath tumors."
supports: SUPPORT
evidence_source: OTHER
snippet: "Recent advances in genomic studies identified previously unrecognized critical involvement of polycomb repressor complex 2 (PRC2) core components SUZ12 and EED in transition to malignancy."
explanation: This review supports PRC2-core inactivation as a key transition event rather than a late incidental finding.
downstream:
- target: H3K27 Trimethylation Loss
description: PRC2 loss removes the repressive H3K27me3 chromatin mark.
- name: H3K27 Trimethylation Loss
description: >-
PRC2-deficient MPNSTs lose global H3K27 trimethylation, producing a
diagnostically useful biomarker state and reshaping downstream gene
regulation.
biological_processes:
- preferred_term: regulation of gene expression
modifier: ABNORMAL
term:
id: GO:0010468
label: regulation of gene expression
evidence:
- reference: PMID:25240281
reference_title: "PRC2 is recurrently inactivated through EED or SUZ12 loss in malignant peripheral nerve sheath tumors."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MPNSTs with PRC2 loss showed complete loss of trimethylation at lysine 27 of histone H3 (H3K27me3) and aberrant transcriptional activation of multiple PRC2-repressed homeobox master regulators and their regulated developmental pathways."
explanation: This directly links PRC2 loss to the characteristic H3K27me3-loss state and its transcriptional consequences.
downstream:
- target: Developmental Gene Derepression
description: Loss of H3K27me3 releases normally repressed developmental transcriptional programs.
- name: Developmental Gene Derepression
description: >-
Loss of PRC2-mediated repression derepresses homeobox and developmental gene
programs, reinforcing malignant identity rather than normal Schwann-lineage
differentiation.
biological_processes:
- preferred_term: regulation of gene expression
modifier: ABNORMAL
term:
id: GO:0010468
label: regulation of gene expression
evidence:
- reference: PMID:25240281
reference_title: "PRC2 is recurrently inactivated through EED or SUZ12 loss in malignant peripheral nerve sheath tumors."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MPNSTs with PRC2 loss showed complete loss of trimethylation at lysine 27 of histone H3 (H3K27me3) and aberrant transcriptional activation of multiple PRC2-repressed homeobox master regulators and their regulated developmental pathways."
explanation: This supports developmental gene derepression as a specific downstream effect of the PRC2-loss branch.
downstream:
- target: Cell Cycle Deregulation
description: Aberrant developmental transcription cooperates with checkpoint loss to sustain malignant proliferation.
- name: Copy-Number Driven Genomic Instability
description: >-
Large-scale somatic copy-number aberrations are a central evolutionary
feature of MPNST and help stratify clinically relevant branches of disease.
evidence:
- reference: PMID:36598417
reference_title: "Genomic Patterns of Malignant Peripheral Nerve Sheath Tumor (MPNST) Evolution Correlate with Clinical Outcome and Are Detectable in Cell-Free DNA."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Following biallelic inactivation of NF1, loss of CDKN2A or TP53 with or without inactivation of polycomb repressive complex 2 (PRC2) leads to extensive somatic copy-number aberrations (SCNA)."
explanation: This large multiregional genomic study supports copy-number-driven genomic instability as a central consequence of the core MPNST lesion set.
- name: Cell Cycle Deregulation
description: >-
Multiple upstream lesions converge on unchecked MPNST cell growth, making
proliferative drive a final common consequence of the conventional disease
program.
cell_types:
- preferred_term: Schwann cell
term:
id: CL:0002573
label: Schwann cell
biological_processes:
- preferred_term: cell population proliferation
modifier: INCREASED
term:
id: GO:0008283
label: cell population proliferation
evidence:
- reference: PMID:25240281
reference_title: "PRC2 is recurrently inactivated through EED or SUZ12 loss in malignant peripheral nerve sheath tumors."
supports: SUPPORT
evidence_source: IN_VITRO
snippet: "Introduction of the lost PRC2 component in a PRC2-deficient MPNST cell line restored H3K27me3 levels and decreased cell growth."
explanation: This cell-line rescue experiment supports proliferation as a downstream phenotype of the PRC2-loss branch.
- name: SMARCB1 Loss in Epithelioid MPNST
subtypes:
- Epithelioid
description: >-
Epithelioid MPNST follows a subtype-specific chromatin-disruption branch in
which SMARCB1 loss is recurrent, in contrast to the conventional PRC2-loss
signature of most non-epithelioid tumors.
genes:
- preferred_term: SMARCB1
term:
id: hgnc:11103
label: SMARCB1
biological_processes:
- preferred_term: chromatin organization
modifier: ABNORMAL
term:
id: GO:0006325
label: chromatin organization
evidence:
- reference: PMID:30864974
reference_title: "Recurrent SMARCB1 Inactivation in Epithelioid Malignant Peripheral Nerve Sheath Tumors."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Sequencing identified SMARCB1 gene inactivation in 12/16 (75%) EMPNST and all 5 (100%) ESCW through homozygous deletion (N=8), nonsense (N=7), frameshift (N=2), or splice site (N=2) mutations"
explanation: This subtype-specific genomic series supports recurrent SMARCB1 inactivation as a key oncogenic event in epithelioid MPNST.
histopathology:
- name: Spindle Cell Pattern
finding_term:
preferred_term: Spindle Cell Pattern
term:
id: NCIT:C53643
label: Spindle Cell Pattern
description: >-
Conventional MPNST usually shows a spindle-cell sarcoma pattern rather than
overt epithelial or round-cell morphology.
evidence:
- reference: PMID:38954182
reference_title: "Malignant Peripheral Nerve Sheath Tumor, a Heterogeneous, Aggressive Cancer with Diverse Biomarkers and No Targeted Standard of Care: Review of the Literature and Ongoing Investigational Agents."
supports: SUPPORT
evidence_source: OTHER
snippet: "Spindle-cell sarcomas of neural-crest origin, MPNSTs are frequently situated in the extremities and pelvis/trunk, often at the confluence of large nerve roots and bundles."
explanation: This review abstract supports spindle-cell morphology as a core histopathologic descriptor of conventional MPNST.
phenotypes:
- category: Musculoskeletal
name: Enlarging Soft Tissue Mass
diagnostic: true
description: >-
Patients commonly present with a progressively enlarging deep soft tissue
mass, often near a major nerve.
phenotype_term:
preferred_term: Soft tissue neoplasm
term:
id: HP:0031459
label: Soft tissue neoplasm
evidence:
- reference: PMID:36752552
reference_title: "Malignant Peripheral Nerve Sheath Tumors of the Brachial Plexus: A Single-Center Experience on Diagnosis, Management, and Outcomes."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Malignant peripheral nerve sheath tumors must be suspected in enlarging masses (>5 cm) with the constellation of pain, motor, and sensory deficits."
explanation: This clinical series directly supports enlarging mass as a core presenting phenotype of MPNST.
- category: Musculoskeletal
name: Pain
description: >-
Pain is a common presenting symptom and a concerning sign of malignant
transformation in patients with pre-existing neurofibromas.
phenotype_term:
preferred_term: Pain
term:
id: HP:0012531
label: Pain
evidence:
- reference: PMID:36752552
reference_title: "Malignant Peripheral Nerve Sheath Tumors of the Brachial Plexus: A Single-Center Experience on Diagnosis, Management, and Outcomes."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Malignant peripheral nerve sheath tumors must be suspected in enlarging masses (>5 cm) with the constellation of pain, motor, and sensory deficits."
explanation: This supports pain as a common and clinically important MPNST presentation clue.
- reference: PMID:16033085
reference_title: "Malignant peripheral nerve sheath tumors (MPNST) in neurofibromatosis type 1 (NF1): diagnostic findings on magnetic resonance images and mutation analysis of the NF1 gene."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "MRI was performed on 50 patients with NF1 and nerve sheath tumors, of whom 7 had atypical pain, tumor growth or neurological deficits indicative of malignancy"
explanation: In NF1 surveillance, atypical pain is one of the key symptom changes prompting concern for MPNST.
- category: Neurologic
name: Muscle Weakness
description: >-
Motor deficits may develop when the tumor involves or compresses a major
nerve plexus or trunk.
phenotype_term:
preferred_term: Muscle weakness
term:
id: HP:0001324
label: Muscle weakness
evidence:
- reference: PMID:36752552
reference_title: "Malignant Peripheral Nerve Sheath Tumors of the Brachial Plexus: A Single-Center Experience on Diagnosis, Management, and Outcomes."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "All patients with an MPNST had a tumor >8 cm, motor and sensory deficits, and pain."
explanation: This supports motor deficit, represented here with the closest HPO term muscle weakness, as a clinically important manifestation of nerve-involving MPNST.
biochemical:
- name: H3K27me3 Loss
notes: >-
Loss of H3K27 trimethylation is a widely used biomarker of conventional
PRC2-deficient MPNST. Diagnostic performance is strongest in sporadic and
radiation-associated tumors; epithelioid tumors usually retain H3K27me3.
evidence:
- reference: PMID:26645727
reference_title: "Loss of H3K27me3 Expression Is a Highly Sensitive Marker for Sporadic and Radiation-induced MPNST."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "In contrast, the majority of both sporadic (95%) and radiotherapy-related (91%) MPNSTs showed loss of H3K27me3 expression."
explanation: This supports H3K27me3 loss as a practical biomarker for conventional sporadic and radiation-associated MPNST.
- reference: PMID:26645727
reference_title: "Loss of H3K27me3 Expression Is a Highly Sensitive Marker for Sporadic and Radiation-induced MPNST."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Furthermore, all 5 epithelioid MPNSTs retained H3K27me3 labeling."
explanation: This supports retaining epithelioid MPNST as a subtype-specific exception to the conventional PRC2-loss biomarker pattern.
- name: H3K27me2 Loss
notes: >-
H3K27me2 loss is a more specific biomarker of true PRC2 loss than isolated
H3K27me3 loss and may sharpen differential diagnosis.
evidence:
- reference: PMID:31175328
reference_title: "Histone H3K27 dimethyl loss is highly specific for malignant peripheral nerve sheath tumor and distinguishes true PRC2 loss from isolated H3K27 trimethyl loss."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "H3K27me2 loss is limited to malignant peripheral nerve sheath tumors and is highly concordant with H3K27me3 loss (33/34 cases)."
explanation: This supports H3K27me2 loss as a more specific biomarker for PRC2-deficient MPNST.
genetic:
- name: NF1
association: Germline predisposition with biallelic tumor-suppressor loss
gene_term:
preferred_term: NF1
term:
id: hgnc:7765
label: NF1
notes: >-
NF1-associated MPNST typically develops after loss of the remaining wild-type
NF1 allele in a patient with germline NF1 predisposition.
evidence:
- reference: PMID:24470531
reference_title: "Malignant peripheral nerve sheath tumors."
supports: SUPPORT
evidence_source: OTHER
snippet: "In 50% of cases, they occur in the context of neurofibromatosis type I, characterized by loss of function mutations to the tumor suppressor neurofibromin; the remainder arise sporadically or following radiation therapy."
explanation: This supports NF1/neurofibromin loss as the defining predisposition lesion in a major subset of MPNST.
- name: CDKN2A
association: Somatic deletion or loss
gene_term:
preferred_term: CDKN2A
term:
id: hgnc:1787
label: CDKN2A
notes: >-
CDKN2A loss is an early and recurrent checkpoint-disrupting event in
conventional MPNST.
evidence:
- reference: PMID:25240281
reference_title: "PRC2 is recurrently inactivated through EED or SUZ12 loss in malignant peripheral nerve sheath tumors."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Additionally, we identified frequent somatic alterations of CDKN2A (81% of all MPNSTs) and NF1 (72% of non-NF1-associated MPNSTs), both of which significantly co-occur with PRC2 alterations."
explanation: This large cohort confirms recurrent CDKN2A loss in established MPNST.
- name: TP53
association: Somatic loss of function
gene_term:
preferred_term: TP53
term:
id: hgnc:11998
label: TP53
notes: >-
TP53 loss is a common secondary tumor-suppressor lesion that cooperates with
NF1 and CDKN2A pathway disruption.
evidence:
- reference: PMID:29118384
reference_title: "The genomic landscape of malignant peripheral nerve sheath tumors: diverse drivers of Ras pathway activation."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "We report recurrent mutations in NF1, SUZ12, EED, TP53 and CDKN2A in our study cohort."
explanation: This genomic study confirms TP53 as a recurrent MPNST driver lesion.
- name: SUZ12
association: Somatic PRC2-core loss of function
gene_term:
preferred_term: SUZ12
term:
id: hgnc:17101
label: SUZ12
notes: >-
SUZ12 is one of the two core PRC2 genes most frequently inactivated in
conventional MPNST.
evidence:
- reference: PMID:25240281
reference_title: "PRC2 is recurrently inactivated through EED or SUZ12 loss in malignant peripheral nerve sheath tumors."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Using comprehensive genomic approaches, we identified loss-of-function somatic alterations of the Polycomb repressive complex 2 (PRC2) components (EED or SUZ12) in 92% of sporadic, 70% of NF1-associated and 90% of radiotherapy-associated MPNSTs."
explanation: This directly supports SUZ12 loss as a recurrent conventional-MPNST driver.
- name: EED
association: Somatic PRC2-core loss of function
gene_term:
preferred_term: EED
term:
id: hgnc:3188
label: EED
notes: >-
EED is the second major recurrent PRC2-core lesion in conventional MPNST.
evidence:
- reference: PMID:25240281
reference_title: "PRC2 is recurrently inactivated through EED or SUZ12 loss in malignant peripheral nerve sheath tumors."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Using comprehensive genomic approaches, we identified loss-of-function somatic alterations of the Polycomb repressive complex 2 (PRC2) components (EED or SUZ12) in 92% of sporadic, 70% of NF1-associated and 90% of radiotherapy-associated MPNSTs."
explanation: This directly supports EED loss as a recurrent conventional-MPNST driver.
- name: SMARCB1
subtype: Epithelioid
association: Somatic loss of function in epithelioid subtype
gene_term:
preferred_term: SMARCB1
term:
id: hgnc:11103
label: SMARCB1
notes: >-
Epithelioid MPNST commonly shows SMARCB1/INI1 loss instead of the canonical
PRC2-loss signature.
evidence:
- reference: PMID:30864974
reference_title: "Recurrent SMARCB1 Inactivation in Epithelioid Malignant Peripheral Nerve Sheath Tumors."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Epithelioid malignant peripheral nerve sheath tumors (EMPNST) are characterized by diffuse S-100 and SOX10 positivity, frequent immunohistochemical loss of SMARCB1 expression (70%), and rare association with neurofibromatosis type 1."
explanation: This supports SMARCB1 loss as a defining genetic and diagnostic feature of the epithelioid subtype.
treatments:
- name: Wide Surgical Resection
description: >-
Surgery with negative margins is the chief curative treatment for localized
MPNST.
therapeutic_modality: SURGERY
treatment_term:
preferred_term: surgical procedure
term:
id: NCIT:C15329
label: Surgical Procedure
evidence:
- reference: PMID:38954182
reference_title: "Malignant Peripheral Nerve Sheath Tumor, a Heterogeneous, Aggressive Cancer with Diverse Biomarkers and No Targeted Standard of Care: Review of the Literature and Ongoing Investigational Agents."
supports: SUPPORT
evidence_source: OTHER
snippet: "Although surgery with wide excisional margins is now the chief curative approach to localized disease, MPNST-specific survival has not improved in decades."
explanation: This review directly supports wide-margin surgery as the chief curative treatment for localized MPNST.
- name: Radiation Therapy
description: >-
Radiotherapy is used for local control, especially in high-grade or margin-
threatening disease, although benefit appears context-dependent.
therapeutic_modality: RADIOTHERAPY
treatment_term:
preferred_term: Radiation Therapy
term:
id: NCIT:C15313
label: Radiation Therapy
evidence:
- reference: PMID:27281262
reference_title: "Malignant Peripheral Nerve Sheath Tumors: A Single Institution's Experience Using Combined Surgery and Radiation Therapy."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Combination therapy with surgery and RT provides favorable LC."
explanation: This single-institution cohort supports radiotherapy as part of local-control management for localized MPNST.
- reference: PMID:40795877
reference_title: "The role of radiotherapy in MPNST and the impact of NF1 status on outcomes: Insights from a multicenter cohort study."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "While RTx did not affect overall survival, it reduced LR risk in sporadic cases"
explanation: This multicenter cohort refines radiotherapy use by showing more robust local-control benefit in sporadic disease than in NF1-associated disease.
- name: Ifosfamide-Based Chemotherapy
description: >-
Anthracycline/ifosfamide-based chemotherapy remains a sarcoma-style systemic
treatment option for advanced, metastatic, or downstaging settings, but the
benefit is still uncertain and no targeted standard of care exists.
treatment_term:
preferred_term: chemotherapy
term:
id: NCIT:C15632
label: Chemotherapy
therapeutic_agent:
- preferred_term: ifosfamide
term:
id: CHEBI:5864
label: ifosfamide
evidence:
- reference: PMID:38954182
reference_title: "Malignant Peripheral Nerve Sheath Tumor, a Heterogeneous, Aggressive Cancer with Diverse Biomarkers and No Targeted Standard of Care: Review of the Literature and Ongoing Investigational Agents."
supports: SUPPORT
evidence_source: OTHER
snippet: "For advanced and metastatic MPNST, radiation and chemotherapy (chiefly with anthracyclines plus ifosfamide) have somewhat promising but still largely uncertain treatment roles, chiefly in local control, downstaging, and palliation."
explanation: This review supports anthracycline/ifosfamide-style chemotherapy as a current but still uncertain systemic option in advanced MPNST.
- reference: PMID:28546782
reference_title: "Neoadjuvant Ifosfamide and Epirubicin in the Treatment of Malignant Peripheral Nerve Sheath Tumors."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Our data suggest that MPNSTs do respond to epirubicin and ifosfamide based chemotherapy and prospective studies are warranted to further define the clinical benefit."
explanation: This small retrospective neoadjuvant series provides direct human evidence that ifosfamide/anthracycline-based chemotherapy can induce radiographic response.
classifications:
icdo_morphology:
classification_value: Sarcoma
evidence:
- reference: PMID:24470531
reference_title: "Malignant peripheral nerve sheath tumors."
supports: SUPPORT
evidence_source: OTHER
snippet: "Malignant peripheral nerve sheath tumors (MPNST) are uncommon, biologically aggressive soft tissue sarcomas of neural origin that pose tremendous challenges to effective therapy."
explanation: This classifies MPNST as a soft tissue sarcoma.
harrisons_chapter:
- classification_value: ONCOLOGY_HEMATOLOGY
evidence:
- reference: PMID:38954182
reference_title: "Malignant Peripheral Nerve Sheath Tumor, a Heterogeneous, Aggressive Cancer with Diverse Biomarkers and No Targeted Standard of Care: Review of the Literature and Ongoing Investigational Agents."
supports: SUPPORT
evidence_source: OTHER
snippet: "Malignant peripheral sheath tumor (MPNST) is a rare, aggressive form of soft-tissue sarcoma that presents a unique set of diagnostic and treatment challenges and is associated with major unmet treatment medical needs."
explanation: This supports classification of MPNST as a malignant cancer entity.
- reference: PMID:24470531
reference_title: "Malignant peripheral nerve sheath tumors."
supports: SUPPORT
evidence_source: OTHER
snippet: "Malignant peripheral nerve sheath tumors (MPNST) are uncommon, biologically aggressive soft tissue sarcomas of neural origin that pose tremendous challenges to effective therapy."
explanation: This supports classifying MPNST within the solid-tumor sarcoma space.
mappings:
mondo_mappings:
- term:
id: MONDO:0017827
label: malignant peripheral nerve sheath tumor
mapping_predicate: skos:exactMatch
mapping_source: MONDO
mapping_justification: Primary MONDO disease identifier for the disease-level MPNST curation entry.
notes: "Requested NCIT cross-reference: NCIT:C3798. This entry remains MONDO-first at the disease level because the schema currently provides explicit MONDO mapping slots but not structured NCIT disease/subtype mappings. Per cancer curation guidance from #1198, subtype grounding here is used only for facet-style ontology alignment and does not imply separate dismech pages or Not Yet Curated badges."
datasets:
- accession: geo:GSE303418
title: Selective inhibition of BRAF and CRAF sensitizes NF1-deficient malignant peripheral nerve sheath tumors to MEK inhibitors
description: 'Background: Treatment for patients with malignant peripheral nerve sheath tumors (MPNST) is an unmet clinical need. Loss of NF1 in MPNST leads to hyperactivation of RAS oncoproteins, however little is known about relevant downstream oncogenic signaling and effective targeted therapies in MPNST are still lacking. Methods: Conditional gene expression, CRISPR-CAS9, and shRNA-mediated knockdown were used to perform gain/loss-of-function experiments to explore the effect of reconstituting the GTPase-activating protein-related domain of NF1 or knockdown of A/B/CRAF kinases on ERK signaling output and MPNST cell growth.'
organism:
preferred_term: human
term:
id: NCBITaxon:9606
label: Homo sapiens
data_type: BULK_RNA_SEQ
sample_count: 36
publication: PMID:41023593
notes: Identified by GEO DataSets index search for Malignant Peripheral Nerve Sheath Tumor (scripts/discover_datasets.py); accession and metadata verified against NCBI E-utilities on 2026-08-01. Title, sample count, and organism are GEO's own values.
- accession: geo:GSE283902
title: Hydroxychloroquine prevents resistance and potentiates antitumor effect of SHP2 inhibition in NF1-associated Malignant Peripheral Nerve Sheath Tumors
description: Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive sarcomas and the primary cause of mortality in patients with neurofibromatosis type 1 (NF1). These malignancies develop within pre-existing benign lesions called plexiform neurofibromas (PNs). PNs are solely driven by biallelic NF1 loss eliciting RAS pathway activation and respond favorably to MEK inhibitor therapy. MPNSTs harbor additional mutations and respond poorly to MEK inhibition. Our analysis of genetically engineered and orthotopic patient-derived xenograft MPNST tumor models indicates that MEK inhibition has poor anti-tumor efficacy.
data_type: BULK_RNA_SEQ
sample_count: 31
publication: PMID:39793045
notes: Identified by GEO DataSets index search for Malignant Peripheral Nerve Sheath Tumor (scripts/discover_datasets.py); accession and metadata verified against NCBI E-utilities on 2026-08-01. Title, sample count, and organism are GEO's own values.
- accession: geo:GSE275048
title: The CoREST complex is a therapeutic vulnerability in malignant peripheral nerve sheath tumors (RNA-Seq)
description: Malignant peripheral nerve sheath tumor (MPNST) is a highly aggressive sarcoma that may be seen in patients with neurofibromatosis type 1 (NF1) or occur sporadically. While surgery is the primary treatment for localized MPNST with a 61.9% overall survival rate, metastatic disease is often fatal due to resistance to systemic therapies which underscores the urgent need for effective treatments. MPNSTs frequently harbor inactivating driver mutations in the PRC2 epigenetic repressor complex suggesting epigenetic therapies may represent a specific vulnerability in these tumors.
organism:
preferred_term: human
term:
id: NCBITaxon:9606
label: Homo sapiens
data_type: BULK_RNA_SEQ
sample_count: 16
publication: PMID:40128216
notes: Identified by GEO DataSets index search for Malignant Peripheral Nerve Sheath Tumor (scripts/discover_datasets.py); accession and metadata verified against NCBI E-utilities on 2026-08-01. Title, sample count, and organism are GEO's own values.
- accession: ega:EGAS00001004899
title: Personalised therapy with MEK inhibition leads to a sustained complete response in an adolescent patient with a recurrent malignant peripheral nerve sheath tumor
description: The prognosis of recurrent malignant peripheral nerve sheath tumors (MPNST) is dismal, with surgical resection being the only definitive salvage therapy. Treatment with chemo-radiation approaches has not significantly improved patient outcomes. Similarly, trials of therapies targeting MPNST genomic drivers have thus far been unsuccessful. Improved understanding of the molecular pathogenesis of MPNST indicates frequent activation of the mitogen activated protein kinase (MAPK) cell signaling pathway. MEK inhibitors have shown activity in preclinical studies; however, their clinical efficacy has not been reported to date.
organism:
preferred_term: human
term:
id: NCBITaxon:9606
label: Homo sapiens
notes: 'European Genome-phenome Archive study, matched because the disease is named in the study''s own title ("Malignant Peripheral Nerve Sheath Tumor"); description-level mentions were not accepted. EGA study_type: Other. Controlled access -- data require a Data Access Agreement. EGA metadata retrieved 2026-08-01.'
- accession: ega:EGAS00001005065
title: Genomic Landscape of Malignant Peripheral Nerve Sheath Tumor-like Melanoma
description: Malignant peripheral nerve sheath tumor (MPNST)-like melanoma is a rare malignancy with overlapping characteristics of both neural sarcoma and melanoma. The genomics of MPNST-like melanoma have not been previously described. This study provides the results of whole exome and transcriptome sequencing analysis of 8 samples from 6 patients with confirmed diagnosis of MPNST-like melanoma. This study demonstrates that MPNST-like melanoma shares oncogenic alterations common to both cutaneous melanoma and MPNST, and also suggests that MPNST-like melanoma harbors unique genomic and transcriptomic alterations.
organism:
preferred_term: human
term:
id: NCBITaxon:9606
label: Homo sapiens
notes: 'European Genome-phenome Archive study, matched because the disease is named in the study''s own title ("Malignant Peripheral Nerve Sheath Tumor"); description-level mentions were not accepted. EGA study_type: Other. Controlled access -- data require a Data Access Agreement. EGA metadata retrieved 2026-08-01.'
- accession: ega:EGAS00001006069
title: Genomic landscape of malignant peripheral nerve sheath tumor (MPNST)
description: Neurofibromatosis type 1 (NF1) is the most common tumor predisposition syndrome, and is associated with an aggressive soft-tissue sarcoma, malignant peripheral nerve sheath tumours (MPNSTs), the greatest cause of morbidity and mortality in people with NF1. The only potentially curative therapy involves surgery which is not always possible. Even therapy with curative intent is associated with poor overall survival for both sporadic and NF1-related MPNSTs. The development of novel therapies has been largely hindered by a lack of understanding of the molecular events underpinning MPNST pathogenesis.
organism:
preferred_term: human
term:
id: NCBITaxon:9606
label: Homo sapiens
notes: 'European Genome-phenome Archive study, matched because the disease is named in the study''s own title ("Malignant Peripheral Nerve Sheath Tumor"); description-level mentions were not accepted. EGA study_type: Other. Controlled access -- data require a Data Access Agreement. EGA metadata retrieved 2026-08-01.'
Date: 2026-04-12
This curation explicitly follows the cancer-modeling guidance called out from
dismech issue #1198.
disease_term is MONDO-first: MONDO:0017827 malignant peripheral nerve sheath tumor.NCIT:C3798 is recorded in the disease-level notes as the requested disease
cross-reference, and NCIT histopathology grounding was used for
NCIT:C53643 Spindle Cell Pattern.NF1-Associated, Sporadic, Radiation-Associated)
and histology (Epithelioid, Malignant Triton Tumor).Epithelioid remained inside the parent MPNST page even though it has a
subtype-specific SMARCB1 branch, because the broader disease still shares a
common MPNST clinical/pathologic frame and the schema can represent the
distinct mechanism with subtype-scoped nodes.MONDO:0017827 malignant peripheral nerve sheath tumorMONDO:0004540 epithelioid malignant peripheral nerve sheath tumorMONDO:0016757 malignant triton tumorNCIT:C53643 Spindle Cell PatternCL:0002573 Schwann cellGO:0007265 Ras protein signal transductionGO:0000075 cell cycle checkpoint signalingGO:0006974 DNA damage responseGO:0006325 chromatin organizationGO:0010468 regulation of gene expressionGO:0008283 cell population proliferationHP:0031459 Soft tissue neoplasmHP:0012531 PainHP:0001324 Muscle weaknessMAXO:0000004 surgical procedureMAXO:0000014 radiation therapyMAXO:0000647 chemotherapyCHEBI:5864 ifosfamidePMID:24470531 Farid et al. 2014 reviewKey quote used: "In 50% of cases, they occur in the context of neurofibromatosis type I ... the remainder arise sporadically or following radiation therapy."
PMID:38954182 Somaiah et al. 2024 review
PMID:36598417 Cortes-Ciriano et al. 2023NF1 biallelic loss -> CDKN2A/TP53 +/- PRC2 loss -> extensive SCNAs.Also supports the H3K27me3-loss branch as a distinct evolutionary path.
PMID:29118384 Brohl et al. 2017
Used for recurrent NF1, SUZ12, EED, TP53, and CDKN2A lesions and
for convergent Ras-pathway activation.
PMID:30722027 Pemov et al. 2019
Used to keep the progression model atomic:
CDKN2A/B deletion is an early step in PN -> atypical neurofibroma
transition, whereas PRC2 loss is later.
PMID:25240281 Lee et al. 2014
SUZ12 / EED inactivation across etiologiesH3K27me3 lossPMID:26645727 Prieto-Granada et al. 2016Used for H3K27me3-loss diagnostic performance and the fact that epithelioid tumors retain H3K27me3.
PMID:31175328 Marchione et al. 2019
H3K27me2-loss biomarker.PMID:25602794 Jo and Fletcher 2015Used for epithelioid subtype morphology, superficial distribution, diffuse S100 positivity, and infrequent NF1 association.
PMID:30864974 Schaefer et al. 2019
Used for subtype-scoped SMARCB1 inactivation in epithelioid MPNST.
PMID:17149968 Stasik and Tawfik 2006
PMID:36752552 Donaldson et al. 2023Used for enlarging mass, pain, and motor/sensory deficit presentation.
PMID:16033085 Friedrich et al. 2005
Used for NF1 surveillance language around atypical pain, tumor growth, and neurologic deficits as malignant-warning features.
PMID:27281262 Bishop et al. 2018
Used for combined surgery plus radiotherapy and local-control outcomes.
PMID:40795877 Jansma et al. 2025
Used to refine radiotherapy interpretation: lower local-recurrence risk in sporadic disease, unclear benefit in NF1-associated disease.
PMID:28546782 Hirbe et al. 2017
SMARCB1 branch. Under the #1198 rule set, that would only
be warranted if it needed a genuinely separate disease-level mechanism graph.
Here, subtype-scoped mechanism and genetic nodes are sufficient.NF1 Biallelic Inactivation, Ras Pathway Hyperactivation, CDKN2A/B Loss,
TP53 Pathway Loss, PRC2 Core Complex Inactivation, H3K27 Trimethylation Loss,
Developmental Gene Derepression, and Copy-Number Driven Genomic Instability.