This analysis showed that correlation of expression was more statistically significant in tumors with the following characteristics: 1) negative for ER; 2) negative for progesterone receptor; 3) basal-like histology; 4) positive for pathological lymph nodes; 5) positive for Ki-67 protein status; 6) pathological tumor size 3 (pT3); 7) grade 3 (G3). The gene discussed is ESR1; the disease is neoplasm.