Our results are consistent with and further strengthen the evidence provided by Anderson et al.28 However, only a modest or no BCSS difference was detected in the present study in the comparison among the ER-positive/PR-negative, ER-negative/PR-positive, and ER-negative/PR-negative subtypes in several subgroups with a small number of patients, including men, black individuals, and those with grade IV BC. This evidence concerns the gene ESR1 and breast cancer.