文摘
PurposeIt is unknown whether Jim Crow—i.e., legal racial discrimination practiced by 21 US states and the District of Columbia and outlawed by the US Civil Rights Act in 1964—affects US cancer outcomes. We hypothesized that Jim Crow birthplace would be associated with higher risk of estrogen-receptor-negative (ER−) breast tumors among US black, but not white, women and also a higher black versus white risk for ER− tumors.