Clinical verification of plasma messenger RNA as novel noninvasive biomarker identified through bioinformatics analysis for lung cancer

Lung cancer (LC) remains associated with significant mortality worldwide. The lack of reliable noninvasive biomarkers and targeted therapies contributes to poor survival rate. Herein, we initially took advantage of the public microarray data from Oncomine database to filter messenger RNAs (mRNAs) as potential biomarkers. Subsequently, clinical validation was applied to identify candidate noninvasive biomarkers in plasma from patients with LC. Through comprehensive analysis of transcriptional expression profiles across 12 studies, top 6 over- and underexpressed mRNAs were generated. Then, a pair of matched plasma samples from LC patient and normal control was detected by RT-PCR, and three genes with positive bands were selected for further validation. Finally, qPCR was conducted to further assess values of the three identified genes. We displayed with high confidence that two cell-free mRNAs (HJURP and ADAMTS8) were expressed at significantly levels compared to normal controls. Receiver-operating characteristic (ROC) curves on the diagnostic efficacy of plasma HJURP and ADAMTS8 mRNAs in LC diagnosis showed that the area under the ROC (AUC) was 0.6960 and 0.6877; sensitivity was 66.0% and 83.7%; specificity was 78.6% and 71.4%, respectively. Combined ROC analyses using these two biomarkers revealed an elevated AUC of 0.75. Furthermore, the higher HJURP level could be associated with early-stage LC while lower ADAMTS8 level could be correlated with non-small cell lung cancer. Collectively, circulating HJURP and ADAMTS8 mRNAs are promising noninvasive biomarkers for LC diagnosis. Our integrative strategy provides new insights into novel noninvasive biomarker identification for other types of cancer.