Large GWAS Study Finds DNA Variants Linked to Risk of Developing Breast Cancer

The use of advanced gene mapping techniques in the current study enabled investigators to identify 352 risk variants within these regions. So far, it is not yet clear how many genes these variants target, but the investigators have identified 191 genes with reasonable confidence.

In the majority of cases, the variants affected gene expression, how active a particular gene was and how much of a particular protein it created, rather than altering the type of protein coded by the gene. Of the newly-discovered genetic variants, about a third predispose women towards developing hormone-responsive breast cancer, the type of disease found in 80% of breast cancer patients. These tumors respond to hormonal treatments such as tamoxifen. In contrast, 15% of the genetic variants predispose women to the rarer estrogen-receptor-negative type of breast cancer.

"We know from previous studies that variants across our DNA contribute towards breast cancer risk, but only rarely have scientists have been able to identify exactly which genes are involved," said first author Dr. Laura Fachal researcher in human genetics at the Wellcome Sanger Institute. "We need this information as it gives us a better clue to what is driving the disease and hence how we might treat or even prevent it."

"This incredible haul of newly-discovered breast cancer genes provides us with many more genes to work on, most of which have not been studied before," said senior author Dr. Alison Dunning, reader in molecular cancer genetics at the University of Cambridge. "It will help us build up a much more detailed picture of how breast cancer arises and develops. But the sheer number of genes now known to play a role emphasizes how complex the disease is."

The breast cancer genome-wide association study was published in the January 7, 2020, online edition of the journal Nature Genetics

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University of Cambridge
Wellcome Sanger Institute