SMAD4 and metastatic malignant neoplasm in the lymph nodes: In terms of clinicopathology parameters, 9 studies have data that can be extracted, SMAD4 mutations were associated with tumor location (odds ratio [OR] = 1.15, colon/rectum, 95% CI 1.01–1.31, P = 0.042), TNM stage (OR = 1.28, stage IV/I–III, 95% CI 1.03–1.58, P = 0.025), lymph node metastasis (OR = 1.42, N1 + N2/N0, 95% CI 1.20–1.67, P < 0.001), mucinous differentiation (OR = 2.23, 95% CI 1.85–2.70, P < 0.001) and rat sarcoma viral oncogene homolog (RAS) mutation status (OR = 2.13, 95% CI 1.37–3.34, P = 0.001).