Research finds new genes with links to breast cancer

At the present time genetic tests for breast cancer only look for a few genes such as BRCA1, BRCA2, and PALB2. However, these genes explain only a small part of the genetic risk, so it looks as if there are more breast cancer genes to be identified.

An international collaboration has now identified new genes linked to breast cancer that could eventually be included in tests to pinpoint women with an increased risk of the disease.

Researchers looked at genetic changes in all genes in 26,000 women with breast cancer and 217,000 women without it, including women from eight countries in Europe and Asia.

Professor Douglas Easton of Cambridge University, who co-led the study, says: “To our knowledge, this is the largest study of its kind. It was made possible through the use of data from multiple collaborators in many countries, as well as publicly available data from the UK Biobank.”

The team found at least four new breast cancer risk genes but just as important is the suggestive evidence for many others. The team says ­identification of these new genes will improve our understanding of the genetic risk of breast cancer and help better identify women at risk.

Professor Jacques Simard of ­Université Laval, in Quebec, Canada, and co-lead of the study, said: “Although most of the variants identified in these new genes are rare, the risks can be significant for women who carry them.

“For example, alterations in one of the new genes, MAP3K1, appear to give rise to a particularly high risk of breast cancer.”

The findings will also help new approaches to breast screening, risk reduction and cure. The aim is to ­integrate the latest information into a tool that predicts risk currently being used worldwide by doctors.

Professor Simard added: “Improving genetic counselling for high-risk women will promote shared ­decision-making regarding risk ­reduction strategies, screening and determination of treatment options.”

Before this information can be used by doctors in clinics, however, scientists feel the need to validate the results in more groups of women.

Professor Easton added: “We need additional data to determine more precisely the risks of cancer associated with variants in these genes, to study the characteristics of the tumours, and to understand how these genetic effects combine with other lifestyle factors affecting breast cancer risks.”

The discovery of these novel genes also provides crucial information on the biological mechanisms underlying cancer development, which could open the way to new treatments.