| Gene/Alteration | Frequency (%) | Type of Alteration | Pathway Involved | Clinical Significance | Evidence Sources |
|---|---:|---|---|---|---|
| **RAS** (NRAS, HRAS, KRAS) mutations | Common in FTC; reported among the major/primary driver events in follicular-patterned thyroid tumors; exact FTC-specific prevalence not uniformly stated in retrieved sources | Activating point mutations | MAPK; also PI3K/AKT cross-talk | Early/truncal driver of FTC; associated with follicular-patterned phenotype, tumor initiation, and propensity for vascular invasion; part of the “RAS-like” molecular class used in risk stratification (pqac-00000003, pqac-00000004, pqac-00000009) | (pqac-00000003, pqac-00000004, pqac-00000009, pqac-00000012) |
| **PAX8-PPARG** fusion | Common/recurrent in FTC; older reviews cited in retrieved papers note it as a characteristic FTC alteration, but no single consistent percentage is given in the accessible excerpts | Chromosomal rearrangement / gene fusion | PI3K/AKT-associated biology; follicular differentiation programs | Supports FTC diagnosis in follicular-patterned tumors; implicated in tumorigenesis and used in molecular classification of follicular lesions (pqac-00000003, pqac-00000010) | (pqac-00000003, pqac-00000010) |
| **PTEN** loss / mutation | Recurrent but less common than RAS; frequency not consistently quantified in retrieved excerpts | Inactivating mutation, deletion, or loss of function | PI3K/PTEN/AKT | Promotes FTC initiation/progression via derepression of PI3K signaling; relevant to aggressive biology and dedifferentiation when combined with other events (pqac-00000003, pqac-00000009) | (pqac-00000003, pqac-00000009) |
| **PIK3CA / AKT1 / broader PI3K pathway alterations** | Recurrent in FTC and more advanced follicular-cell derived thyroid cancers; exact FTC-specific percentage not consistently stated in retrieved excerpts | Activating mutations / pathway activation | PI3K/AKT/mTOR | Important for FTC initiation and progression; contributes to less differentiated/aggressive disease and potential therapeutic vulnerability (pqac-00000003, pqac-00000007, pqac-00000009) | (pqac-00000003, pqac-00000007, pqac-00000009) |
| **TP53** mutations | Rare in well-differentiated FTC; enriched in poorly differentiated/anaplastic progression; 26% in PDTC and ~80% in ATC across thyroid cancers | Inactivating point mutation / tumor suppressor loss | p53 / cell-cycle checkpoint pathways | Late event associated with dedifferentiation, genomic instability, and progression from differentiated thyroid carcinoma to high-grade disease rather than typical early FTC initiation (pqac-00000000, pqac-00000003, pqac-00000009) | (pqac-00000000, pqac-00000003, pqac-00000009) |
| **TERT promoter** mutations | Present across thyroid cancer histologies, with substantially higher prevalence in aggressive/undifferentiated tumors; exact FTC-specific prevalence not consistently stated in retrieved excerpts | Promoter mutation causing telomerase activation | Telomere maintenance; cooperates with MAPK/PI3K-driven oncogenesis | Strong marker of aggressiveness, dedifferentiation, recurrence, and poor outcomes; considered a progression event rather than a typical sole initiating lesion (pqac-00000000, pqac-00000003, pqac-00000004, pqac-00000009) | (pqac-00000000, pqac-00000003, pqac-00000004, pqac-00000009) |
| **MAPK pathway dysregulation** | Core molecular theme in most follicular-cell derived thyroid cancers; in FTC often driven by RAS rather than BRAF | Pathway-level constitutive activation | RTK-RAS-RAF-MEK-ERK (MAPK) | Central determinant of thyroid tumor phenotype; in FTC, lower/"RAS-like" MAPK output is linked to follicular architecture and differentiation state; relevant for molecular classification and targeted therapy development (pqac-00000003, pqac-00000004, pqac-00000009) | (pqac-00000003, pqac-00000004, pqac-00000009) |
| **PI3K/PTEN/AKT pathway dysregulation** | Core molecular theme in FTC; repeatedly emphasized as critical in FTC initiation | Pathway-level activation via **RAS**, **PIK3CA**, **AKT1**, **PTEN** loss | PI3K/AKT/mTOR | Especially important in FTC biology versus papillary carcinoma; linked to tumor growth, survival, dedifferentiation, and progression to advanced disease (pqac-00000003, pqac-00000004, pqac-00000009) | (pqac-00000003, pqac-00000004, pqac-00000009) |
| **Loss of heterozygosity (LOH) / chromosomal imbalance** (e.g., 16p12.1, 3p21.31, 12q24.11-q24.13) | In one microarray study, total LOH events were higher in FTC than FTA (18 vs 15); specific recurrent regions varied by cohort | Chromosomal copy-number/allelic imbalance | Mixed; includes regions harboring cancer-related genes such as **TP53**, **PTPN11** | Suggests genomic instability and partially shared background with follicular adenoma, while some rearrangements may help distinguish malignant FTC from benign FTA (pqac-00000008) | (pqac-00000008) |
| **FTC vs FTA transcriptomic hub genes** (**TOP2A, JUN, EGFR, CDK1, FOS, CDKN3, EZH2, TYMS, PBK, CDH1, UBE2C, CCNB2**) | Derived from differential-expression/network analysis rather than mutation prevalence; 598 DEGs identified in one study | Differential expression / network hub dysregulation | p53 signaling, cell cycle, folate/one-carbon metabolism, EGFR-related signaling | Highlights candidate biomarkers and mechanisms of malignant progression distinguishing FTC from follicular adenoma; useful for discovery but not yet established routine clinical markers (pqac-00000006) | (pqac-00000006) |


*Table: This table summarizes the principal genetic and pathway-level alterations reported for follicular thyroid carcinoma, emphasizing drivers, progression events, and potential diagnostic or prognostic relevance. It is useful for quickly mapping specific genes to the molecular mechanisms and clinical behavior of FTC.*