Isocitrate Dehydrogenase 1 Is a Novel Plasma Biomarker for the Diagnosis of Non–Small Cell Lung Cancer

Purpose: Effective biomarkers for the diagnosis of non–small cell lung cancer (NSCLC) are needed. We previously showed that isocitrate dehydrogenase 1 (IDH1) is significantly increased in NSCLC tumors. This study aimed to examine the plasma levels of IDH1 in a large patient population to evaluate its effectiveness in NSCLC diagnosis. Experimental Design: The plasma levels of IDH1, CA125, Cyfra21-1, and CEA were assayed by ELISA. Blood samples were obtained from 1,422 participants (943 patients with NSCLC and 479 healthy controls). The samples were randomly divided into a training set and a test set. Receiver operating characteristic and binary logistic regression analyses were applied to evaluate diagnostic efficacy and establish diagnostic mathematical models. Results: Plasma IDH1 levels were significantly higher in patients with NSCLCs than in healthy controls ( P P Conclusions: IDH1 can be used as a plasma biomarker for the diagnosis of NSCLCs, particularly lung adenocarcinoma, with relatively high sensitivity and specificity. Clin Cancer Res; 19(18); 5136–45. ©2013 AACR .