ESR1 and breast cancer: A meta-analysis of African ancestry cohorts and European ancestry cohorts from Breast Cancer Association Consortium (BCAC) found four loci associated with overall BC risk (1p13.3, 5q31.1, 15q24 and 15q26.3) and two with ER negative BC (1q41 and 7q11.23), with modest contributions from the African cohorts16.