GSTM1 and cancer: Comparing study group patients with PVs in BRCA1 to the CDB revealed statistically significant differences in single-gene expression in 12 of the 16 cancer genes and in 2 gene group scores, all in a direction that contributed to higher RS results in the study patients (lower expression in study group patients vs the CDB in ESR1, PGR, SCUBE2, GSTM1, BAG1, and the ER gene group score; higher expression in CCNB1, KI67, STK15, SURV, MYBL2, CTSL2, and CDK68, and the proliferation gene group score).