The aim of this study was to quantify the contribution of the founder mutations prevalent in Portugal (BRCA2 c.156_157insAlu and BRCA1 c.3331_3334del) for cancers associated with HBOC other than the common female breast, ovarian, and prostate cancer, more specifically, the rarer pancreatic, male breast, peritoneal, and fallopian tube cancers. This evidence concerns the gene BRCA1 and cancer.