Prognostic value of MMP9 activity level in resected stage I B lung adenocarcinoma

The clinical outcomes of patients with early-stage non-small cell lung cancer (NSCLC) have remained unsatisfactory after complete surgical resection. The objective of this study was to explore the prognostic value of matrix metalloproteinase 9 (MMP9) activity level in Chinese patients with stage I B lung adenocarcinoma. A sensitive and validated method was employed for determining the activity of MMP9 in human lung adenocarcinoma cells in vitro. Then, the association was examined between the level of MMP9 enzymatic activity and clinical outcomes. A total of 104 cases were stratified according to the IASLC/ATS/ERS classification scheme and activity of MMP9 was analyzed by SensoLyte® assay kit. The results showed that the MMP9 activity was the highest in solid predominant and micropapillary predominant subtypes, intermediate in acinar predominant and papillary predominant subtypes, and the lowest in lepidic predominant subtype. Multivariate analysis revealed that pathological subtype and activity of MMP9 were independent prognostic factors for disease-free survival (DFS), respectively (P = 0.005 and 0.029). Significant relationship existed between enzyme activity of MMP9 and prognosis. And the 30 months DFS of high- and low-level MMP9 activity tumors was 44.2% and 84.1% (P < 0.0001), respectively. High-level MMP9 activity is correlated with aggressive tumor behaviors and poor clinical outcomes in early-stage lung adenocarcinoma after complete resection.