Exploring the genome of male breast cancer

Male breast cancer, which represents less than 1 percent of all breast cancer cases each year, has increased at a much faster rate than in women over the last 40 years. Unaware of the risk, breast cancer in males tends to be diagnosed at more advanced stages and hence, have poorer treatment outcomes.

For the study, researchers detected mutations in multiple genes within tumor samples from 10 patients, known to drive cancer growth. They also identified structural variants—places in the genome where DNA has broken and rearranged—that impact five other cancer-associated genes. Two men had variations in the BRCA2 gene that impairs DNA repair, a common cause of breast cancer in women. Along with an extended study group of 18 additional tumor samples, about 21 percent of the tumors had 10 to 20 excess copies of the FGFR1 gene, which is linked to treatment-resistant tumors in some women with breast cancer.

Cancer therapies are readily available to target the genetic variations identified in 8 of the 10 men, opening new pathways for treatment. For example, drugs such as immunotherapy and PARP inhibitors might be effective for men with BRCA2 gene variations and a high number of tumor mutations. Cancer-triggering rearrangements in the NTRK1 gene may respond to drugs called kinase inhibitors. In addition, the gene mutations identified may lead to the discovery of new targeted therapies.

“Though larger studies will need to done to confirm the research results, the novel findings suggest that tailoring treatments for this under-studied male patient population will be necessary,” said the authors.

Reference: Dr. Majd Al Assaad, Dr. Juan Miguel Mosquera, Sandra and Edward Meyer; JOURNAL: Modern Pathology