Prognostic value and clinicopathologic significance of nm23 in various cancers: A systematic review and meta-analysis

•The low nm23 expression significantly predicted the poorer survival for cancer patients.•The low nm23 expression was significantly correlated with the lymph node metastasis.•The expression of nm23 in patients at N0 stage was obviously higher than the patients with breast carcinoma at N1-N3 stage.•The expression of nm23 in cancer tissues may serve as an important factor for evaluating the presence of lymph node metastasis.