Analysis of 100 Studies Reveals 32 New Sites of Genetic Variation Linked to Breast Cancer

165
One of the major scientific crusades in oncology has been to identify and validate biomarkers associated with recurrent breast cancer. [iStock / royaltystockphoto]

An analysis of data from over 100 studies including 266,000 women has unearthed 32 previously undiscovered areas in the genome where DNA variation appears to influence a women’s risk for developing breast cancer.

The multinational research used information collected by the UK-based Breast Cancer Association Consortium over the last 15 years. New methods were used in the analysis that identified variants that can have different effects for different types of cancer.

“The findings from this analysis enhance our understanding of the biology that differentiates subtypes and may improve our ability to predict women’s breast cancer risks, even at the level of specific breast cancer subtype,” commented Nilanjan Chatterjee, PhD, a professor at Johns Hopkins Bloomberg School of Public Health and one of the lead researchers on the study, which was published in the journal Nature Genetics.

Breast cancer is one of the most common cancers and over 250,000 women are diagnosed every year in the US alone, with 40,000 succumbing to the disease annually. Having a better method of assessing risk is therefore crucial to help assess screening needs and also to better personalize treatment if women develop the disease.

These new variants, add to more than 170 previously discovered genetic variants that influence risk for breast cancer. Of the 32 identified by the researchers to be linked more generally to breast cancer risk, seven were associated with estrogen receptor status—overexpression of estrogen receptors are seen in 70% of breast cancer cases; seven to the grade of the tumor; four to HER2 receptor status—the HER2 gene is often mutated in breast cancers and around 30% of treatments target this protein; and two to progesterone receptor status.

Five of the newly discovered variants seemed to be linked to a greater risk for some types of breast cancer, but a lower risk of others.

“These variants are special and if followed up properly may lead to important insights into the biology of these breast cancer subtypes,” commented Chatterjee.

A key difference between this study and previous similar analyses was that earlier studies have focused on assessing overall risk for developing breast cancer, or looked at some subtypes with relatively simple genetics, such as the BRCA1/2 mutations that dramatically increase a woman’s risk for developing breast cancer. This study used a technique that allowed them to assess genetic associations with the new variants in the presence of a lot of different background characteristics such as known presence of other genetic variants and other environmental factors.

Although this analysis was very large, including 142,798 breast cancer cases and 123,283 controls, the large majority of women were of European ancestry. Chatterjee and his colleagues plan to replicate their research in even larger, more ethnically diverse populations in future to try and pinpoint additional mutations that might not be present in European populations.

This site uses Akismet to reduce spam. Learn how your comment data is processed.