Hongfei Gao, Yilong Wu

Guangdong Lung Cancer Institute, Guangdong GeneralHospital

Objective:Immunohistochemistry (IHC) and fluorescentin situ hybridization (FISH) are reliable ways to identify over expression ofc-Met protein or amplification of the c-Met gene, but each technique requires ahigh-quality tissue sample, which may not be available. The aim of this studyis to investigate whether plasma soluble c-Met level can be used to predicttissue c-Met status in patients with advanced non-small cell lung cancer(NSCLC). 

Method: In 198 patients with advanced NSCLC, we determinedc-Met expression by IHC analysis on tumors. The expression was scored accordingto MetMAb scoring criteria. Plasma concentration of soluble c-Met protein wasmeasured with a human soluble c-Met quantitative enzyme-linked immunosorbentassay (ELISA) kit, and the predictive values were determined based on thereceiver-operating characteristic (ROC) curves analysis. 

Result: Of thetotal 198 patients, 103 (52%) patients were tissue c-Met negative, 95(48%) weretissue c-Met positive. The average plasma c-Met concentration was 682.8±155.2ng/mLin the tissue c-Met-negative group, significantly lower than 886.5±307.4ng/mLin tissue c-Met- positive group (P<0.001). ROC curve analysis showed66.9% specificity and 64.2% sensitivity for predicting tissue c-Met positivityat 755ng/mL of plasma c-Met. AUC for plasma c-Met was 0.724 (95% confidenceinterval; 0.654–0.794, P<0.001). 

Conclusion: We suggest 755ng/mLin the plasma as a cutoff for predicting tissue c-Met status with moderatespecificity and sensitivity. This information may be useful when the tumour tissueis not available.

Key Words: advanced NSCLC  cMet soluble cMet