ESR1 and metastatic malignant neoplasm in the lymph nodes: In the low MUC1 group (n = 11), larger tumors, higher nuclear grade, lymph node metastasis, and negativity for estrogen receptor was more frequently identified compared to the high MUC1 group (n = 11; p = 0.01, p = 0.002, p = 0.008, and p = 0.02, respectively).