Male breast cancer is rare, affecting around 400 men in the UK each year, compared with around 50,000 women diagnosed, and knowledge of the disease and what causes it is extremely limited. This study is one of the first steps towards understanding the causes of male breast cancer.
In a collaboration between Breakthrough Breast Cancer and The Institute of Cancer Research (ICR), the team studied 433 male breast cancer cases and looked at the 12 most common genes that contribute to risk of breast cancer in females. They showed that five of these genes significantly affect risk in men too, but that the extent of risk was different between the sexes.
These results come from analysing data from the Male Breast Cancer Study, the world's largest study into the causes of male breast cancer, a partnership between Breakthrough Breast Cancer and the ICR.
Study author Dr Nick Orr, from the Breakthrough Breast Cancer Research Centre at the ICR in London, said: "We need to understand if the biology of male breast cancer is essentially the same as breast cancer in women or something different. This study suggests there are many similarities, with subtle differences in the effects of genes which cause breast cancer.
“While we are at an early stage with this work, these results give rise to the possibility of tailored treatments for male breast cancer patients.”
The team also believe that the results could improve understanding of the genetic causes of female breast cancer as well. Some of the results will be taken into analyses of the Breakthrough Generations Study, which is following 100,000 UK women for 40 years to find the causes of female breast cancer.
Co-leader of the Male Breast Cancer Study, Professor Anthony Swerdlow from the ICR, said: “It is exciting that this study is already producing results because we know so little about male breast cancer. We hope that this work will provide us with a much better understanding of the disease and allow us to find ways to prevent it.
“A further benefit of this work is that it could provide insights that can be transferred across to finding new genetic factors for female breast cancer. We are at the start of this work and look forward to finding out much more about this disease.”