BRCA1 methylation

BRCA1 methylation

The local hypermethylation of BRCA1 (Breast Cancer Susceptibility Protein-1), a tumour suppressor gene, coupled with global DNA hypomethylaton at CpG islands, which are characteristic of BRCA1-related cancers of the breast and presumably also of the ovaries.

Mechanism
BRCA1 prevents global DNA hypomethylation by upregulating expression of DNMT1, which encodes a methylation maintenance enzyme that is a transcriptional target of BRCA1. Reduced expression of BRCA1 correlates with reduced levels of DNMT1 and reduced methylation of CpG islands.

Molecular pathology
BRCA1 methylation is associated with medullary carcinoma and metaplastic carcinoma.