Expression of tissue inhibitor of metalloproteinase‐3 (TIMP‐3) and its prognostic significance in resected non‐small cell lung cancer

BACKGROUND AND OBJECTIVES: Tissue inhibitor of metalloproteinase-3 (TIMP-3) inhibits the activity of metalloproteinases that play important roles in development and progression of malignant tumors. We conducted a retrospective study of TIMP-3 expression in resected non-small cell lung cancer (NSCLC). METHODS: TIMP-3 expression was examined immunohistochemically in primary tumor specimens from 143 patients who underwent complete resection for NSCLC. Correlations between TIMP-3 expression grade and tumor histology, TNM classification, MMP-2 and MMP-9 expression grade, VEGF expression grade, intra-tumoral microvessel density, proliferative index, apoptosis index, and prognosis were analyzed. RESULTS: TIMP-3 expression was low in 40, moderate in 71, and high in 32 patients. Higher TIMP-3 expression was seen in squamous cell carcinoma than in adenocarcinoma (P = 0.001), and reduced TIMP-3 expression was significantly associated with nodal involvement (P = 0.016) and advanced pathologic stage (P = 0.036). MMP-2 expression was reduced along with enhanced TIMP-3 expression (P = 0.010). The 5-year overall survival rates of low, moderate, and high TIMP-3 patients were 53, 64, and 84%, respectively (P = 0.037). Multivariate analysis confirmed that enhanced TIMP-3 expression was an independent factor for a favorable prognosis (P = 0.037). CONCLUSIONS: TIMP-3 expression status was significantly correlated with pathologic stage and nodal involvement, and was an independent prognostic factor in resected NSCLC.