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Pérdida de función RB1 (proteína del retinoblastoma)

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IDBIO-RB1
TipoBiomarcador
Aliaces
Pérdida de RB1 / mutación del gen del retinoblastomaВтрата функції RB1 (ретинобластомний білок)
Situaciónreviewed 2026-05-04 | pending_clinical_signoff
EnfermedadesDIS-SCLC DIS-UROTHELIAL
FuentesSRC-EAU-BLADDER-2024 SRC-NCCN-SCLC-2025

Datos sobre biomarcadores

Tipo de biomarcadorgene_mutation
Detalles de la mutación{"exon": "multiple (exons 1–27)", "functional_impact": "loss-of-function", "gene": "RB1", "variant_type": "loss-of-function (deletion, frameshift, nonsense, splice, missense inactivating)"}
Medición
MétodoTumor NGS; IHC (Pérdida de proteína Rb por IHC — usada clínicamente en el diagnóstico de SCLC); FISH para la deleción de 13q14 (retinoblastoma)
Consulta de la capacidad de acción{"gene": "RB1", "variant": "loss_of_function"}
Productos químicos y químicosBIO-CDKN2A

Notas

RB1 encodes the retinoblastoma protein (pRb), the master G1/S checkpoint regulator. pRb normally sequesters E2F transcription factors to prevent S-phase entry; loss of pRb → uncontrolled cell cycle progression. Clinical contexts: (1) Hereditary retinoblastoma: germline RB1 mutation → bilateral/multifocal retinoblastoma in childhood; lifetime elevated risk of osteosarcoma, SCLC, melanoma. (2) SCLC: biallelic RB1 loss + TP53 mutation defines the SCLC molecular signature (~95% of SCLC). pRb loss by IHC is used in pathologic diagnosis. No targeted therapy for RB1 deficiency per se; SCLC treatment is chemotherapy (EP/EC) ± atezolizumab. (3) Urothelial carcinoma: RB1 alterations in ~30% of muscle-invasive bladder cancer; associated with basal/squamous subtype; not currently targeted. (4) Breast cancer: RB1 mutations occur in ~10% of TNBC; RB1 loss predicts resistance to CDK4/6 inhibitors (palbociclib, ribociclib, abemaciclib) — pRb is the substrate for CDK4/6 that drives cell cycle entry; without pRb, CDK4/6 inhibition is ineffective. (5) Osteosarcoma: RB1 alterations in ~30%. Therapeutic implication of RB1 loss in HR+ breast cancer: CDK4/6 inhibitors are essentially non-functional with...

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