• What is BCOR?
  • BCOR in Myelodysplastic Syndromes
  • BCOR Mutations
  • Clinical Trials

BCOR

BCL6 corepressor (BCOR) is a gene that encodes a protein of the same name. BCOR is a member of the ankyrin repeat domain containing gene family. The corepressor expressed by BCOR binds to BCL6, a DNA-binding protein that acts as a transcription repressor for genes involved in regulation of B cells, a type of immune cell (Gene 2014a, 2014b; Genetics Home Reference 2014). In cancer, BCOR mutations have been observed in myelodysplastic syndromes, endometrial cancer, and other cancers.​

Contributors: Stephen A. Strickland, M.D., MSCI, Annette S. Kim, M.D., Ph.D.

Suggested Citation: Strickland, S., A. Kim. 2014. BCOR. My Cancer Genome https://www.padiracinnovation.org/content/disease/myelodysplastic-syndromes/bcor/?tab=0 (Updated September 23).

Last Updated: September 23, 2014

BCOR in Myelodysplastic Syndromes

BCOR mutations occur in 2.8–4.2% of MDS (COSMIC; Damm et al. 2013). BCOR mutations are most often observed in refractory cytopenia with multilineage dysplasia (RCMD) and refractory anemia with excess blasts (RAEB), two subtypes of high risk MDS (Cazzola, Della Porta, and Malcovati 2013). BCOR mutations tend to co-occur with RUNX1 or DNMT3A mutations (Damm et al. 2013). The role of BCOR mutations in cancer is not yet understood; however, BCOR mutations tend to be frameshift or nonsense mutations (COSMIC; Tiacci et al. 2012) and are located throughout the gene (Damm et al. 2013). This and other features have led to the hypothesis that BCOR mutations result in the loss of function of a tumor suppressor gene (Tiacci et al. 2012).

BCOR mutations are a prognostic biomarker, associated with shorter overall survival and higher likelihood of transformation to AML (Damm et al. 2013).​

Contributors: Stephen A. Strickland, M.D., MSCI, Annette S. Kim, M.D., Ph.D.

Suggested Citation: Strickland, S., A. Kim. 2014. BCOR in Myelodysplastic Syndromes. My Cancer Genome https://www.padiracinnovation.org/content/disease/myelodysplastic-syndromes/bcor/ (Updated September 23).

Last Updated: September 23, 2014

BCOR Mutations in Myelodysplastic Syndromes

Properties
Location of mutations BCOR gene on Xp11.4
Frequency of BCOR mutations in MDS 2.8–4.2% (COSMIC; Damm et al. 2013)
Implications for Targeted Therapeutics
Response to bromodomain inhibitors, DOT1L inhibitors, or other targeted epigenetic therapies Unknown at this timea
Response to spliceosome-targeting therapies Unknown at this timeb
Response to Ras-targeting therapies Unknown at this timec

BCOR mutations are a prognostic biomarker, associated with shorter overall survival and higher likelihood of transformation to AML (Damm et al. 2013).

a Bromodomain (BRD2, BRD3, BRD4, and BRDt) inhibitors and DOT1L inhibitors are in phase I studies in hematologic malignancies (Abdel-Wahab and Levine 2013). In addition, several other epigenetic targeted therapies, targeting IDH1/IDH2, EZH2, LSD1, or UTX/JMJD3, are in development (Abdel-Wahab and Levine 2013).

b Drugs targeting the spliceosome are in development; these drugs alter gene expression or affect alternative splicing in ways that inhibit cancer progression (Bonnal, Vigevani, and Valcarcel 2012).

c Efforts to develop Ras-targeting therapies are in progress and are hoped to be useful in hematologic malignancies (Ward, Braun, and Shannon 2012).

Contributors: Stephen A. Strickland, M.D., MSCI, Annette S. Kim, M.D., Ph.D.

Suggested Citation: Strickland, S., A. Kim. 2014. BCOR Mutations in Myelodysplastic Syndromes. My Cancer Genome https://www.padiracinnovation.org/content/disease/myelodysplastic-syndromes/bcor/321/ (Updated September 23).

Last Updated: September 23, 2014

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