ESR1 and neoplasm: For luminal A-classified tumors in the combined Affymetrix data set, improved DMFS was observed for luminal-simple samples compared with non-luminal-simple samples (Figure 4c), further supported by multivariate analysis (n = 225, P = 0.004; HR = 0.36; 95% CI = 0.18-0.73) using LN status, ER status, tumor size, and histologic grade (grade 3 versus 1 and 2) as covariates.