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Mutation / troncation de la perte de fonction de l'APC

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IDBIO-APC
TypeBiomarqueur
Alias
Mutation APCМутація втрати функції APC (усікання)
Étatreviewed 2026-05-04 | pending_clinical_signoff
MaladiesDIS-CRC
SourcesSRC-ESMO-CRC-2024 SRC-NCCN-COLON-2025

Données biomarqueurs

Type de biomarqueurgene_mutation
Détails de la mutation{"exon": "multiple; hotspot cluster region codons 1286–1513 (mutation cluster region, MCR)", "functional_impact": "loss-of-function", "gene": "APC", "variant_type": "loss-of-function (nonsense, frameshift, large deletion, splice; MCR hotspot for somatic CRC)"}
Mesure
MéthodePanneaux NGS tumoraux; NGL germinatif (sang) pour FAP/AFAP; IHC (accumulation nucléaire de β-caténine comme substitut)
Recherche de la faisabilité{"gene": "APC", "variant": "loss_of_function"}
Biomarqueurs connexesBIO-CTNNB1 BIO-KRAS BIO-TP53 BIO-SMAD4

Notes

APC (Adenomatous Polyposis Coli) is the gatekeeper tumor suppressor of the WNT/β-catenin pathway. APC forms the destruction complex with AXIN1/2, GSK-3β, and CK1α that phosphorylates β-catenin (CTNNB1) at exon 3 residues (S33/S37/T41/S45) targeting it for proteasomal degradation. Loss of APC → β-catenin accumulates, translocates to the nucleus, activates TCF/LEF transcription of MYC, CCND1, and pro-proliferative genes. Frequency: somatic APC mutation in ~80% of sporadic CRC (earliest event in adenoma-carcinoma sequence). Germline: FAP (familial adenomatous polyposis) — >100 adenomas, nearly 100% CRC risk by 40y without colectomy; AFAP (attenuated FAP) — fewer adenomas, later onset. Clinical relevance: APC mutation is diagnostic/prognostic context in CRC; no APC-targeted therapy approved. Surrogate: nuclear β-catenin by IHC confirms WNT pathway activation when sequencing unavailable.

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Pertinence thérapeutique

Biomarqueur