In the multivariate regression analysis of 283 patients, the risk for recurrence in the L group did not differ from the H group (HR = 1.065, 95% CI 0.318–3.566; P = 0.918), and the mortality risk in the L group was 2.606 times than the H group (95% CI 0.685–9.913); nevertheless, the differences were not significant at the statistical analysis (P = 0.160) and does not indicate that ER-low positivity is an independent risk factor of OS rates in the ER+/PR+/HER2 breast cancer patient populations studied. This evidence concerns the gene ESR1 and breast cancer.