Performance of Cancer/Testis Antigens and EEF1A2 mRNAs measured by qRT‐PCR as tissue biomarkers for NSCLC

Abstract

Candidate genes were cloned into TOPO TA plasmids (Invitrogen) to serve as standards in a qRT‐PCR assay in which copy numbers for the candidate biomarker genes were normalized to 106 copies of β‐actin. A panel of biomarkers was selected to directly test sensitivity and specificity in frozen tissue samples from 103 NSCLC, 60 matched non‐malignant tissue samples from the same resected lung specimens and 18 normal lung tissue samples from never smokers. Mean copy numbers/106 copies β‐actin are shown below.Performance of individual markers and combinations of markers was analyzed by ROC. Maximum AUC for an individual marker was obtained for MAGE A (0.712 tumor vs adjacent lung and 0.784 tumor vs never smoker lung). AUC for the combined five gene panel was 0.885 for tumor versus adjacent lung, 0.957 for tumor vs never smoker lung and 0.945 for adjacent lung vs never smoker lung. A logistic model using percentiles had an AUC of 0.814 for tumor vs adjacent lung. We conclude that rigorous marker by marker testing in tumor tissue may yield candidate RNA biomarkers that can be assembled into a highly sensitive and specific panel.