Anna Li, Feiyu Niu, Jinji Yang, XuchaoZhang, Qing Zhou, Jian Su, Zhi Xie, Nana Lou, Jiefei Han, HuajunChen, Haiyan Tu, Wenzhao Zhong, Ning Zhao, Chongrui Xu, ZhengWang, Binchao Wang, Yisheng Huang, Zhihong Chen, Shiliang Chen, Ying Huang, SuqingYang, Yilong Wu

Guangdong Lung Cancer Institute, Guangdong GeneralHospital

Objective:The cellular-mesenchymal-epithelialtransition protein (MET) has recently been identified as a novel promisingtarget in non-small-cell lung cancer (NSCLC) treatment. The relevance between de novo MET expression and theoutcome still remained unclear. 

Method: We reviewed the data of ourpatients who had been diagnosed with NSCLC between December 2013 and October2014. All the patients were evaluated the MET expression status. MET proteinexpression was evaluated by immunohistochemistry (IHC) using a CONFIRManti-total c-MET Rabbit monoclonal primary antibody (SP44, Ventana, Arizona, #7904430)and using an ultra View Universal DAB(#760700, Ventana), We used a standardprotocol for immunostaining samples. Staining was performed on a VentanaBenchmark XT automated immunostainer (Ventana Medical Systems). Tumorcytoplasmic and cell membrane immunohistochemical staining intensity and extentof MET was classified H-score system (the sum of each intensity score×%), Therange is from 0-300, cases with H-score.

Result: There were 158 advanced NSCLC patients with MET dataavailable for analysis. Of them, according to MET H-score criteria IHC positiverate is 48.1%(76/158). There are more patients with adenocarcinoma in METpositive group compared with MET negative group (P=0.01). All of the 9cases with lymphoepithelioma-like carcinoma were not MET expression. The METexpression, age, sex, cigarette smoking history and pathology were used ascovariates in a multivariate Cox regression model, but none of them wasindependent prognostic factor. There was no significant difference in overallsurvival time between MET positive and negative patients (mOS 18.9 months [95%CI:10.5-27.3] vs. 23.5 months [10.4-36.6], P=0.22). Neither has significantdifference in efficacy (Z=-0.44, P=0.66) or PFS of 1st line chemotherapybetween the MET positive and negative patients (mPFS 6.8 months [95% CI: 5.4-8.2]vs. 5.9 months [5.5-6.3], P=0.92). There was no significant differencein PFS between regimens either in MET positive or negative patients. 

Conclusion:Our data showed that de novo METexpression wasn't rare. It wasn't the predictive or prognostic factor in stageIV NSCLC patients, which should be confirmed in larger population.

Key Words: Non-small cell lungcancer  MET  Chemothrapy