Variants confer a modest risk but their high frequency implicates them in 11% of breast cancers, according to Nature Genetics paper.
An international group of researchers discovered that two common SNPs on chromosome 5 are associated with risk of estrogen receptor-positive (ER+) breast cancer.
The team analyzed genotypic data from almost 40,000 patients and control subjects from five countries. They found that more than 60% of the general population carry at least one copy of the risk variant of the most important SNP called rs4415084. The scientists also discovered that women who have inherited the variant from both parents are at an approximately 50% greater risk of developing ER+ breast cancer than women who have not inherited the variant.
The second variant is located close to the first variant and occurs only in tandem with it, adding a slight risk of the disease. Although these variants confer modest risk, they are so common that they are estimated to account for approximately 11% of breast cancers overall, according to deCODE, which was part of the research team.
The analysis also revealed that a fourth known set of variants, located on chromosome 10q26 and accounting for approximately 16% of breast cancers, appear to exclusively confer a risk of ER+ tumors.
“One of the most pressing next steps in this research is to analyze these results in large cohorts of women of non-European descent,” notes Kari Stefansson, CEO of deCODE.
The paper was published on April 27 in the online edition of Nature Genetics.