Compared with female breast cancer, methylation was less common in male breast cancer in several of the studied genes, particularly ESR1, BRCA1 and BRCA2. BRCA1 and BRCA2 promoter hypermethylation was encountered in, respectively, 2% and 18% of the male breast cancers, but was seen in 18% and 64% of the female breast cancers, using the same approach and similar cutoff criteria. Here, ESR1 is linked to breast cancer.