Methylation of promoter region of BRCA1 gene versus pathogenic variants of gene: risk factor or clinical marker of breast cancer.

We proved that hypermethylation of the BRCA1 gene promoter is a risk factor for breast cancer and possibly an early biological marker of clinical onset, as its presence contributed to rapid disease progression with metastasis. The high frequency of hypermethylation in the examined breast cancer patients may be a consequence of environmental factors pressure on the risk of the disease development. Further large-scale studies are needed for the clinical application of the results.