Genetic Predisposition to Male Breast Cancer: A Case Series

Background/Aim: Male breast cancer (MBC) is a very rare disorder affecting approximately 1 in 833 men. Genetic predisposition is one of the most important risk factors of MBC with BRCA2 being the most commonly mutated gene in males diagnosed with breast cancer. However, a large part of MBC heritability is still unexplained. This study sought to add to the data already available on the genetics of MBC. Materials and Methods: Our study initially involved comprehensive analysis of BRCA1 and BRCA2, followed by analysis of 43 genes implicated in cancer predisposition in a series of 100 Greek patients diagnosed with MBC between 1995-2015. Results: Pathogenic variants were identified in 13 patients, with BRCA2 being the most commonly affected gene, followed by BRCA1, RAD50, RAD51B, and MSH3. Conclusion: In agreement with previous reports, BRCA2 is the most important genetic factor of MBC predisposition, while the remaining known cancer predisposition genes are each very rarely involved, rendering conclusions as to their cumulative effect difficult to draw.