ERBB2 and breast cancer: In comparison, the ESR1 high methylation group had a significantly higher percentage of T4 tumors (5.1 to 2.7%; p < 0.001), distant metastasis status (4.2 to 1.2%; p < 0.001), American Joint Committee on Cancer (AJCC) stage IV (3.4 to 1.0%; p < 0.001), ERα negative (78.8 to 11.5%; p < 0.001), PR negative (83.1 to 21.0%; p < 0.001), HER2 positive (21.2 to 12.8%; p < 0.001), invasive ductal carcinoma (86.4 to 63.9%; p < 0.001) BC patients than the ESR1 low methylation group (Table 2).