BRCA1 and metastatic malignant neoplasm in the lymph nodes: The results of our meta-analysis showed that the BRCA1 promoter methylation was statistically significant correlated with lymph node metastasis (OR = 1.25, 95%CI 1.06–1.48, P = 0.009, Fig. 3) and histological grade 3 (OR = 2.29, 95%CI 1.65–3.18, P < 0.001, Fig. 4), but had no correlation with early age (<50 years) at diagnosis (OR = 1.21, 95%CI 0.98–1.50, P = 0.07, Fig. 5) or premenopausal status (OR = 1.21, 95%CI 0.98–1.50, P = 0.08, Fig. 6).