In a cohort of 298 ER+ breast cancer patients who were treated with tamoxifen alone for 5 years [13], we observed a significant negative association between EPRS mRNA expression and recurrence-free survival (KM = 2.82e-03, Cox p = 9.42e-03; HR = 2.08) (Figure 2A). The gene discussed is ESR1; the disease is breast cancer.