We used InfiniumMethylationEPIC BeadChip microarray technology (Illumina) and analyzed genome wide methylation patterns (over 850 000 CpG sites) in blood cells of 43 women with one of three BRCA1 founder mutations (mean age=52.91), which were cancer free at the time of sampling and did not develop cancer within 12.9 years of follow up, 29 women with detectable in blood BRCA1 epimutation (mean age=62.69) with 7.22 years follow up, and 19 women with neither mutation nor epimutation, which developed cancer on average 4.62 years from sampling. Here, BRCA1 is linked to cancer.