Defective BRCA gene linked to prostate and pancreatic cancer

Defective versions of the BRCA1 and BRCA2 genes are known to increase the risk of breast and ovarian cancer in both men and women

A study published in the Journal of Clinical Oncology provides the strongest evidence yet for these links and helps researchers more accurately estimate the associated risks

Since these genes were discovered in the mid-1990s, many studies have explored possible links between BRCA1 and BRCA2 mutations and other cancers

To investigate these risk estimates further, a team led by researchers at the University of Cambridge, funded by Cancer Research UK, analysed nearly 3,200 families with one or more members of a BRCA1 mutation and nearly 2,200 families with a BRCA2 mutation.

Based on these data, the researchers estimated that men with a mutation in the BRCA2 gene had a 27 percent risk of developing prostate cancer at age 80, more than double the risk of non-carriers

People who carry defective copies of BRCA1 or BRCA2 more than double their risk of pancreatic cancer to 2.

The mutations were also found to increase the risk of stomach cancer, although the researchers cautioned that the number of patients in their dataset was small due to the rarity of the cancer

Mutations in these two genes significantly increase the risk of breast cancer in men, although the disease remains very rare, accounting for less than 1% of all cancer cases in men in the UK

Researchers have been unable to find convincing evidence that genetic mutations are associated with an increased risk of some other cancers previously thought to be linked to defective BRCA genes, such as melanoma

Cancer Research UK says people concerned about their cancer risk should speak to their GP

Professor Antonio Antonis, who led the study from the Department of Public Health and Primary Care at the University of Cambridge, said: "These large datasets of patients have allowed us to estimate with greater accuracy the degree of error in the BRCA1 and BRCA2 genes that increase the risk of some cancers

Professor Marc Tischkowitz, from the Department of Medical Genetics at the University of Cambridge, added: "Thanks to the data we analysed, the link between BRCA2 and prostate and pancreatic cancer is now much clearer

"Overall, the findings will increase our knowledge in optimizing cancer screening and early detection strategies to help people known to carry these defective genes

Michelle Mitchell, chief executive of Cancer Research UK, said: "Our scientists helped discover BRCA 25 years ago and established that defects in these genes increase the risk of breast cancer

Cancers caused by genetically defective BRCA genes are relatively rare, and age, smoking, diet and other preventable factors also increase the risk of cancer

"Improving our understanding of how genetic defects are associated with certain cancers could allow us to more easily identify those who are at higher risk of developing cancer

article title

Cancer Risks Associated With BRCA1 and BRCA2 Pathogenic Variants.