Prognostic value of matrix metalloproteinase-7 expression in patients with non-small cell lung cancer

The prognostic value of matrix metalloproteinase-7 (MMP-7) for survival of patients with non-small cell lung cancer (NSCLC) remains controversial. We performed a meta-analysis of the literatures to clarify its impact. Trials were selected for meta-analysis if they provided an independent assessment of MMP-7 in NSCLC and reported the analysis of survival data based on MMP-7 status. Pooled hazard ratio (HR) with 95% confidence interval (95% CI) was used to evaluate the associations between MMP-7 expression and survival of NSCLC patients. Heterogeneity and publication bias were also assessed. Seven studies involving 1,446 patients were identified. The combined HR for all studies was 1.28 (95% CI 0.86-1.91; P = 0.22). Subgroup analysis revealed that MMP-7 overexpression had a favorable impact on survival in Caucasians (HR = 0.74; 95% CI 0.55-0.99; P = 0.043) but showed a poor survival prognosis in Asians (HR = 1.74; 95% CI 1.05-2.88, P = 0.031). Its effect also appeared significant when the analysis was restricted to Asian patients with squamous cell cancer (HR =3.42; 95% CI 1.92-6.11, P = 0.000) and adenocarcinoma (HR = 2.1; 95% CI 1.34-3.29, P = 0.001). Our meta-analysis suggests that there are ethnic differences in the clinical significance of MMP-7 expression for patients with NSCLC.