ESR1 and neoplasm: Furthermore, our statistical analysis revealed a significant association of TC2N protein expression with clinical stage (P < 0.001), lymph node metastasis (N) (P < 0.001), tumor size (P = 0.021) and human epidermal growth factor receptor 2 (HER-2) status (P = 0.039), but not with age, histological grade, depth of tumor invasion (T), estrogen receptor (ER) status, progesterone receptor (PR) status and epidermal growth factor receptor (EGFR) status (Fig. 1c–e, Table 1).