Based on the meta-analysis of three studies, no correlation between NDRG1 protein expression and tumor stage was identified (P = 0.18, log OR: 0.34, 95% CI: -0.16-0.84, I2: 24.60%, 179 breast cancer with tumor stage III + IV/318 breast cancer with tumor stage I + II, 3 studies, Fig. 4). The gene discussed is NDRG1; the disease is breast cancer.