ESR1 and neoplasm: Importantly, multivariate analysis within the ER-positive subset showed that PRDX1 was a significant independent predictor of improved RFS (HR = 0.62, 95% CI = 0.40 to 0.96, P = 0.032), BCSS (HR = 0.44, 95% CI = 0.24 to 0.79, P = 0.006) and OS (HR = 0.61, 95% CI = 0.44 to 0.85, P = 0.004), when adjusted for well-established variables such as tumor size, grade, age, nodal, progesterone receptor (PR), Her2 and Ki67 status (Table 2).