Prognostic impact of matrix metalloproteinase‐9 in operable non‐small cell lung cancer

Abstract

We assessed the clinical impact of MMP‐9 expression on long‐term survival in patients with operable non‐small cell lung cancer (NSCLC). Primary tumors of 143 consecutive patients with NSCLC resected completely and without overt distant metastases (pT1‐4, pN0‐2, M0, R0) were examined for MMP‐9 expression using immunohistochemistry with a polyclonal, affinity‐purified rabbit antibody that recognizes both latent and active MMP‐9. Immunohistochemical staining of tumor cells was evaluated in comparison to normal bronchiolar epithelium that served as an internal positive control. MMP‐9 expression was categorized into negative, ≤5% tumor cells stained; heterogeneous, >5% and p = 0.016). Multivariate regression analysis including pT‐status, pN‐status, tumor histology and tumor grading showed an independence of this prognostic impact of homogeneous MMP‐9 expression (p = 0.045). Thus, immunohistochemical evaluation of MMP‐9 expression may provide a basis for the preselection of patients to be included in trials investigating specific protease inhibitor therapy after surgical resection of NSCLC.