In gastric cancer, loss of Smad4 staining was found to be significantly associated with the rate of lymph node metastasis (OR = 2.11, 95% CI: 1.03–4.34; Pheterogeneity = 0.038) but not with tumor histology (OR = 0.87, 95% CI: 0.45–1.69; Pheterogeneity = 0.037). Here, SMAD4 is linked to gastric cancer.