In this study, 88.0% of patients were ER-positive, which was similar to the results from Bae et al., who found that there was a significantly higher percentage of ER-positive (87.4% vs.75.9–81.3%) and PR-positive (75.7% vs. 62.4–73.0%) diseases among patients with N1mic breast cancer than patients with N0 and N1a breast cancers (28). The gene discussed is ESR1; the disease is breast cancer.