NDRG1 and metastatic malignant neoplasm in the lymph nodes: No correlation between NDRG1 protein expression and axillary lymph node metastasis according to the random effects model (P = 0.16, log OR: 0.47, 95% CI: -0.18-1.12, I2: 24.16%, 4 studies, Supplementary Fig. 3).