ESR1 and metastatic malignant neoplasm in the lymph nodes: Among all cases, 173 (63.2%) patients had a large tumor size (>2 cm), 136 (49.6%) patients had lymph node metastases, 172 (62.8%) patients had estrogen receptor- (ER-) positive tumors, 149 (54.4%) patients had progesterone receptor- (PR-) positive tumors, and 71 (25.8%) patients had HER2-positive tumors.