Prognostic effect of matrix metalloproteinase-9 in patients with resected Non small cell lung cancer

BACKGROUND: The role of tumor matrix metalloproteinase-9 (MMP-9) expression in non-small cell lung cancer (NSCLC) remains controversial. In this study, we investigated the prognostic value of tumor MMP-9 expression and other clinicopathologic factors in patients with completely resected NSCLC. METHODS: This retrospective study included patients who underwent complete resection of pathological stage I–IIIA NSCLC at Severance Hospital, Seoul, Korea, between 1998 and 2009. Tumor samples of 417 patients were stained by immunohistochemistry, and the expression of MMP-9 in tumor cells was evaluated, using the median immunohistochemical score of 10 (range, 0-300) as the cut-off. RESULTS: Tumor MMP-9 expression was observed in 161 (38.6%) of 417 patients. Log-rank analysis showed a significant association of tumor MMP-9 expression with shortened disease-free survival (p = 0.01) but not with overall survival (p = 0.109). Multivariate analysis demonstrated that tumor MMP-9 expression was not an independent prognostic factor of recurrence (p = 0.142) or survival (p = 0.807). However, among patients with adenocarcinoma, tumor MMP-9 expression was associated with relapse (p = 0.003) and poor survival (p = 0.033). Furthermore, tumor MMP-9 expression was an independent prognostic indicator of relapse in patients with adenocarcinoma (p = 0.035). CONCLUSIONS: Among patients with NSCLC, tumor MMP-9 expression was associated with poor outcomes in those with adenocarcinoma, but not in those with squamous cell carcinoma. In addition, MMP-9 expression was identified as an independent predictor of relapse of completely resected lung adenocarcinoma.