The Prognostic Impact Of High Met Gene Copy Number On Non-Small Cell Lung Cancer: A Meta-Analysis Of Eight Studies.

e22049 Background: The risk stratification of NSCLC on the basis of molecular information is a key approach in the clinical management of patients with the disease. MET is the receptor for HGF and is present in the membrane of NSCLC cells. The most common genetic alteration associated with MET is the gene amplification. Methods: Two independent investigators applied parallel search strategies with the terms "MET" AND "lung cancer", "MET" AND "NSCLC", "met gene copy number" AND "prognosis" in PubMed through November 2012. We selected the studies that investigated the association of MET gene copy number with prognosis. A quality score that assessed the lab methods, the generalizability and the analysis, was assigned to each study that was finally included in the analysis. Results: Among 791 studies that were identified in the initial search, we retrieved 8 cross sectional studies on retrospective cohorts with adequate data regarding the prognostic impact of MET gene copy number on the survival of patients with NSCLC. Among the studies, 5 used FISH and the remaining 3 used RT PCR to assess the MET gene copy number in the primary tumor. All 8 studies used tissue from surgically resected specimens. MET gene copy number predicted worse overall survival when all studies were combined in a fixed effects model (HR=1.35, 95% CI 1.17-1.57). We calculated the I 2 statistic to assess heterogeneity (I 2 =44%, p=0.09). There were four studies where a higher gene copy number predicted a better outcome and four in which the opposite was true. The Egger’s regression intercept showed no significant publication bias (p=0.38). Conclusions: Higher MET gene copy number in the primary tumor at the time of diagnosis predicts worse outcome in patients with NSCLC.