ESR1 and metastatic malignant neoplasm in the lymph nodes: Patients with lymph node metastasis (pN), younger age, premenopausal status, loss of ER and PR in tumors, larger tumor size (pT), and advanced stage showed a trend toward greater hypermethylation, but the trend was not significant (P = 0.051, 0.103, 0.123, 0.119, 0.118, 0.146, 0.250, respectively).