BCOR

Overview

BCOR (BCL6 Corepressor) is a component of a polycomb repressive complex and acts as a transcriptional corepressor. BCOR alterations are found in fusion-negative rhabdomyosarcoma (FN-RMS), where they are a defining feature of a molecularly distinct subtype. In the corpus, BCOR alterations were identified in 30% of FN-RMS patients.

Alterations observed in the corpus

  • BCOR alterations present in 30% of FN-RMS patients (24% of individual samples) in a liquid biopsy multi-sample genomic study tracking RMS progression and relapse (n=35 tumor pairs with ctDNA monitoring) PMID:37730754.
  • BCOR is recurrently mutated in medulloblastoma WES of 92 tumors (Broad cohort), predominantly in the WNT and Group 3/4 subgroups PMID:22820256
  • BCOR is identified as a significantly mutated gene in medulloblastoma WGS/WES from the ICGC cohort of 76 tumors, with subgroup-specific enrichment PMID:22832583
  • Recurrently mutated in CLL (Broad WES, 160 tumors); BCOR mutations identified among significantly mutated genes in chronic lymphocytic leukemia PMID:23415222
  • Most recurrent mutation in sinonasal AdCC (4/21 sequenced tumors, 19%); multiple frameshift/nonsense variants including c.4017_4018insT (p.Asp1340Ter), c.1056dup (p.Thr353HisfsTer28), c.1888_1895del; associated with poor outcome PMID:24418857
  • Novel recurrent driver in 7% of all rhabdomyosarcoma (RMS) cases (Xp11.4): 7 PAX-fusion-negative missense mutations plus 2 focal homozygous deletions plus 1 PAX-fusion-positive indel; BCOR is a chromatin repressor interacting with class I/II HDACs, previously implicated in AML, retinoblastoma, and medulloblastoma PMID:24436047
  • Mutated in 4% of gastric adenocarcinoma overall; especially common in EBV-positive subtype (23%); chromatin-modifier loss in EBV-associated gastric cancer PMID:25079317
  • Mutated in 3/112 Ewing sarcoma cases: S1083I missense, M1259fs frameshift, and a 116-kb intragenic deletion PMID:25223734
  • BCOR significantly co-occurs with trisomy 12 (tri(12)) among 11 significant co-occurrence/mutual-exclusivity pairs in 538 CLL WES cases PMID:26466571
  • BCOR identified as an epigenetic regulator mutated in the advanced thyroid cancer cohort (n=117 PDTC/ATC); reported alongside CREBBP, EP300, and BCL6 as low-frequency epigenetic regulator alterations PMID:26878173
  • BCOR: chromatin regulator in the chromatin-spliceosome AML subgroup with independent adverse prognosis PMID:27276561
  • BCOR-altered sarcoma discussed as a related entity to EWSR1::BEND2 sarcomas (defining alteration for the undifferentiated small round cell sarcoma entity) PMID:28199314
  • R810 mutation detected in 1/19 sequenced 1p/19q-codeleted anaplastic oligodendrogliomas; incidental chromatin-modifier alteration PMID:28472509
  • BCOR is a recurrently altered candidate driver in medulloblastoma, stratified across subgroups in oncoprint analysis PMID:28726821

Cancer types (linked)

  • RMS (Fusion-Negative Rhabdomyosarcoma) — BCOR is one of the defining driver alterations in FN-RMS alongside TP53 mutations and RAS pathway alterations; patients with BCOR alterations may warrant more frequent ctDNA monitoring PMID:37730754.

Co-occurrence and mutual exclusivity

  • BCOR alterations co-occur with TP53 loss-of-function and RAS/PIK3CA pathway alterations in FN-RMS; the co-occurrence pattern supports risk stratification for ctDNA monitoring intervals PMID:37730754.

Therapeutic relevance

  • No direct BCOR-targeted therapy is reported; BCOR status contributes to high-risk FN-RMS identification that may inform intensity of monitoring and future clinical trial eligibility PMID:37730754.

Open questions

  • Whether BCOR alterations are early truncal events or acquired during relapse in FN-RMS, and their relationship to BCOR::CCNB3 fusions described in other RMS series, is not resolved in this corpus PMID:37730754.

Sources

This page was processed by crosslinker on 2026-05-14. - PMID:22820256

This page was processed by crosslinker on 2026-05-14. - PMID:22832583

This page was processed by crosslinker on 2026-05-14. - PMID:23415222

This page was processed by crosslinker on 2026-05-14. - PMID:24418857

This page was processed by crosslinker on 2026-05-14. - PMID:24436047

This page was processed by crosslinker on 2026-05-14. - PMID:25079317

This page was processed by crosslinker on 2026-05-14. - PMID:25223734

This page was processed by crosslinker on 2026-05-14. - PMID:26466571

This page was processed by crosslinker on 2026-05-14. - PMID:26878173

This page was processed by entity-page-writer on 2026-05-15. - PMID:27276561

This page was processed by wiki-cli on 2026-05-14. - PMID:28199314

This page was processed by wiki-cli on 2026-05-14. - PMID:28472509

This page was processed by entity-page-writer on 2026-05-15. - PMID:28726821

This page was processed by wiki-cli on 2026-05-15.