BRCA1 and ovarian cancer: We found that 6.3% of unselected cases of ovarian cancer in this region carried one of 13 causative founder variants in the BRCA1 or BRCA2. This is a lower rate than in other regions of Poland, where the frequency of BRCA1 causative founder variants was observed in about 10–13.5% of ovarian cancer patients [2–8].