Prognostic and clinicopathological value of NM23 expression in patients with breast cancer: A systematic review and meta-analysis

It is hypothesized that, NM23, as a metastasis suppressor gene, may be a good indicator of patients with breast cancer in most reports. The aim of our meta-analysis was to determine the prognostic value of NM23 in patients with breast cancer synthetically, by searching 3 databases, PubMed, EMBASE, and Web of Science, for relevant articles. The inclusion criteria, exclusion criteria, and the standard-of-quality assessment were used according to a previous protocol. The pooled odd ratios (ORs) and corresponding 95% CI were calculated to assess the primary end point, survival data, and the secondary end point, associations between NM23 expression and clinicopathological factors. Finally, funnel plots and Egger׳s linear regression test were used to assess the potential publication bias. Overall, 792 articles were retrieved in the initial search of databases, and 4968 patients were eventually pooled from 26 available studies selected out by 2 independent reviewers. The incorporative OR showed that elevated NM23 expression was associated with better overall survival (OR = 0.62; 95% CI: 0.52-0.74; P < 0.00001; I2 = 0%; Ph = 0.46). In disease-free survival, we also obtained a good prognosis (OR = 0.30; 95% CI: 0.18-0.48; P < 0.00001; I2 = 46%; Ph = 0.13). In addition, high-NM23 expression was correlated with well or moderate histologic grade, negative lymph node metastasis, and early tumor staging. Furthermore, publication bias was detected in overall survival but not in disease-free survival, and it could also be verified by Egger׳s test (P = 0.009 and P = 0.687, respectively). These results implied that NM23 might be an indicator of good prognosis in patients with breast cancer, although further researches need to be performed to confirm the prognostic value of NM23.