BRCA1 and cancer: This suggests that significant gender associated modifiers such as high estrogen levels may affect BRCA1 penetrance over BRCA2. Comparing studies of sporadic MBC [6-8,28-32,35,37-40,44], the median and mean age of onset in our patients is also younger, and this together with the observation of frequent multifocality or bilateral disease reflects the pattern of cancer often seen with underlying genetic predisposition as seen in familial FBC.