Scientists in the UK leading the world’s largest study into the causes of male breast cancer have found a gene that can increase the risk of the disease by up to 50%.

This exciting advance could lead to new treatments for male breast cancer, a disease that is notoriously difficult to study because of its rarity.

Through the Genome-Wide Association Study (GWAS) involving 823 male breast cancer patients, the scientists were able to investigate 447,000 genetic changes.

They then confirmed their results in a further 438 patients.

The breakthrough came when they found that common changes in a gene called RAD51B can increase a man’s breast cancer risk by as much as 50%.

RAD51B is known to play a role in the repair of damaged DNA so, if faulty, this gene might not be able to help protect cells from the build up of DNA damage that can lead to cancer.

But breast cancer in men is still very rare. About 370 men are diagnosed with breast cancer each year in the UK, compared with around 48,400 women.

This landmark study, published in Nature Genetics, represents an international collaboration that set out to find common gene variations that could impact on the heritability of male breast cancer. Although family history of male breast cancer is known to be important to a man’s risk of the disease, the genes involved have so far remained largely elusive. Around one in ten men with breast cancer have faults in the BRCA2 gene, and faults in the BRCA1 gene have been reported less frequently.

“This study represents a leap forward in our understanding of male breast cancer,” said study author Nick Orr from the Breakthrough Breast Cancer Research Centre at The Institute of Cancer Research (ICR). “It shows that while there are similarities with female breast cancer, the causes of the disease can work differently in men. This raises the possibility of different ways to treat the disease specifically for men.”

Anthony Swerdlow, co-leader of the study at The ICR, added, “Male breast cancer is rare, which makes it difficult to study. Through drawing on many hundreds of patients from this country and abroad, we can now start to unravel its causes.”

The scientists are now set to continue this research, to try to find more genes that raise the risk of breast cancer, in order to better understand the causes of this disease in men, and women.


Reference
N Orr, A Lemnrau, R Cooke, et al. Genome-wide association study identifies a common variant in RAD51B associated with male breast cancer risk. Nature Genetics. doi: 10.1038/ng.2417