ESR1 and breast cancer: For example, recent studies by the Breast Cancer Association Consortium have led to the discovery of novel breast cancer susceptibility loci in FGFR2, TNRC9, 8q24, 2q35, and 5p12 that showed stronger association with ER-positive disease than with ER-negative disease [42-45], with fibroblast growth factor receptor also being a direct target of ER.