Gene risk regions for breast cancer approach 100

Scientists from QIMR Berghofer Medical Research Institute and Cambridge University, in collaboration with the international Breast Cancer Association Consortium (BCAC), have identified 15 new gene regions which increase the risk of breast cancer.

Professor Georgia Chenevix-Trench, who heads QIMR Berghofer’s Cancer Program, said the study takes the number of known breast cancer gene susceptibility regions to 94.

The study analysed the genome-wide association data of more than 120 000 women from the international BCAC group.

Professor Chenevix-Trench said once scientists discover more about the consequences of these variants on the expression of genes nearby, they will have a much better understanding of how breast cancer arises, and what can be done to prevent it.

“Already, QIMR Berghofer researcher Dr Jonathan Beesley has been able to predict that three genes, SETBP1, RNF115 and PDZK1 – not previously linked to breast cancer susceptibility – are likely to be involved.”

Professor Chenevix-Trench says including the new variants or ‘typos’ in genetic testing will allow a more accurate prediction of whether a woman is at high or low risk of breast cancer.

“This will give women and their doctors a stronger basis on which to consider screening and prevention,” she said.

Professor Chenevix-Trench said these variants are relatively common and have a more subtle impact than rarer mutations such as BRCA1 and BRCA2.

“While each of these ‘typos’ individually causes only a small increase in cancer susceptibility, a woman who carries a large number of them may be at significantly greater risk,” Professor Chenevix-Trench said.

“Taking into account these 94 variants, we estimate that approximately five per cent of women in the general population have a two-fold increase in their breast cancer risk compared to the average,” Professor Chenevix-Trench said.

“A very small percentage of women (0.7%) have a three-fold increase.”

The study has been published in Nature Genetics: http://www.nature.com/ng/journal/vaop/ncurrent/full/ng.3242.html