This large genome-wide association study identified five new gene locations that contribute to the risk of hereditary breast cancer.

Breast cancer runs in families, but known rare, highly penetrant genes only account for 25 percent of inherited risk. Researchers think that the remaining 75 percent of genetic breast cancer risk probably stems from numerous common genes that on their own contribute only modestly to overall risk but in combination have much greater effect. This study was large enough to detect even variants with small effects.

This two-stage genome-wide association study covered 4,398 breast cancer cases and 4,316 healthy controls in a population of European origin. To confirm what they found, researchers did a third round of testing of 30 variants in 21,860 breast cancer patient cases and 22,578 controls from 22 studies. They found susceptibility gene variants in five locations that showed strong association with breast cancer. Four of these locations contain genes likely to cause breast cancer (FGFR2, TNRC9, MAP3K1 and LSP1).

More: To read an abstract of this paper on PubMed, a medical database, click here.