The Genetics of Male Breast Cancer Are Being Unraveled

Recently, targeted cancer therapies have seen major advances and improved treatment responses. However, the genetics of many cancers have still not been fully determined, and targets for treatment have not been identified. One of these cancers is breast cancer in men.

Male breast cancers account for 1% of all breast cancers

In addition, a large proportion of male breast cancers are estrogen receptor (ER) positive. This suggests that male breast cancers are more homogeneous than breast cancers in women, which may make it easier to identify treatment options. Although knowledge of male breast cancer is quite limited, family history and hereditary predisposition are known to be extremely important risk factors.

Research has found that 10% of male breast cancers carry an inherited BRCA2 mutation. With a very small percentage carrying a BRCA1 mutation, male breast cancers also differ in this respect from breast cancers seen in women.

What have we learned from new research?

A team investigating cancer genetics through genome-wide association studies (GWAS) announced that it had identified 2 gene regions that increase susceptibility to breast cancer in men. Single-nucleotide changes in these gene regions lead to DNA repair gene or tumor-suppressor gene mutations that cause breast cancer to develop.

Although the same gene regions also cause susceptibility to breast cancer in women, they are more serious risk factors for men. The research team repeated the study with more data to investigate on a larger scale and identify more gene regions. They reported identifying 3 new regions in addition to those detected in the previous study. Mutations in these regions were found to be linked to the ER gene and blood vessel formation that triggers tumor development. As reported in the previous study, these regions, which are also associated with breast cancer in women, pose more serious risks for men.

Conclusion

These studies are the largest-scale genetic investigations of male breast cancer. What we have learned represents only a small part of the many unknowns about its genetics, but it is extremely important for identifying appropriate targeted treatments.