We also report, analyzing iCOGS data for more than 23 000 women with germline BRCA1/2 mutations, that common variation in TNFRSF11A, linked to altered RANK expression, may be associated with breast cancer risk in BRCA1 mutation carriers and, furthermore, the survival of patients with ER-negative tumors. Here, TNFRSF11A is linked to breast cancer.