Although rare, breast cancer affects around 350 men each year in the UK. We delve deeply into our research into male breast cancer.

Monday 18 May 2015      Health information blog

This blog is the seventh in a series exploring the achievements of Breast Cancer Campaign and Breakthrough Breast Cancer as both charities work towards launching as one brand new charity (editor's note: now Breast Cancer Now).

Our series continues here with a look at our research into breast cancer in men.

Breast cancer in men

There is a considerable lack of public awareness about breast cancer in men. This doesn’t come as much of a surprise when you try to spot the men living with the disease through the pink fog. But the reality is that, although rare, this is a disease that affects around 350 men each year in the UK.

From a research perspective we know a lot less about male breast cancer than we do about the disease in women. The disease’s rarity in men makes it difficult to collect tissue or blood samples on the same scale as we have seen for women, making research harder to conduct. 

This is why, in 2007, we launched the largest study of its kind collecting blood and lifestyle data to specifically advance research into male breast cancer.

Clearing the pink fog

When the study launched there was a call for participants – both healthy men and those with breast cancer – to donate blood samples. They were also asked to complete a questionnaire to collect information on various aspects of their lifestyle and environmental exposures. 

The idea is that this information can be used to identify the root causes of male breast cancer and provide insight into any biology that overlaps with the disease in women. The study now has more than 1,500 men registered – half of whom have breast cancer. 

Let’s take a look at some of the advances the study has made since it launched.

Obesity, weight and risk

The Male Breast Cancer Pooling Project is an international collaboration of studies, including our own, looking into the causes of male breast cancer. Some of the latest findings from this group showed that breast cancer risk in men increases with weight, and that being obese is associated with an increased risk of about 30%.

Aside from obesity, gynecomastia – the presence of enlarged breast tissue in men – also appeared to have an effect on risk.

Klinefelter syndrome, the presence of an extra X chromosome in men, was confirmed to increase breast cancer risk.

Professor Tony Swerdlow, who leads our Male Breast Cancer Study, said of these results:

“We know that body size can be related to hormone levels. Also, hormonal factors may be the reason why patients with Klinefelter syndrome, who have comparatively low levels of testosterone and high levels of oestrogen, have raised breast cancer risks compared with other men. Our results suggest the need to investigate further the role of sex hormones in causation of breast cancer in men.”

Changes to genetics

In 2012, geneticists working on the Male Breast Cancer Study identified a genetic change which increases risk of the disease in men by up to 50%.  The single letter change to a gene called RAD51B may have an impact on the gene’s function, which in turn could lead to the initiation of cancer. 

As with the identification of other breast cancer genes, such as BRCA or PALB2, this discovery could lead to the development of new ways to identify men at high risk of the disease.

Interestingly, the variation of the RAD51B gene that increases risk in men is not the same one responsible for the increased risk in women. Furthermore, the Male Breast Cancer Study has identified five other genetic variants in other regions of DNA that are specifically associated with breast cancer in men. 

This suggests there may be significant differences in the biology of breast cancer between men and women that need to be considered for further research.

Not gender-specific

Thanks to the Male Breast Cancer Study we are starting to understand more about what causes breast cancer and identify gender-specific risk factors. It’s hoped that in the future these discoveries will help us develop more effective ways to predict breast cancer risk in men and give us the foundations for developing better ways to treat the disease. 

By committing to research specifically focused on male breast cancer we hope that we have begun to cut through the pink fog and show this is a disease that transcends gender.