Li Wan, Lin Zhang, Kai Fan, Jian-Jun Wang

We have previously shown that the long noncoding RNA prostate cancer-associated transcript 6 (PCAT6) promoted the proliferation and invasion of lung adenocarcinoma (LUAD) cells. In this study, the diagnostic significance of tissue and serum PCAT6 was evaluated in non-small cell lung cancer (NSCLC). Tissue expression of PCAT6 was systematically evaluated in five Gene Expression Omnibus datasets (GSE19804, GSE18842, GSE30219, GSE19188, and GSE27262). Circulating and tissue expressions of PCAT6 were detected by quantitative reverse-transcriptase polymerase chain reaction in NSCLC patients from Union Hospital. PCAT6 was significantly increased in lung cancer tissues and could be used to distinguish LUAD from adjacent normal tissues with an area under the receiver operating characteristic curve (AUC) of 0.9210 (p<0.0001; sensitivity, 98.82%; specificity, 78.57%) in GSE30219, 0.9333 (p<0.0001; sensitivity, 86.67%; specificity, 90.77%) in GSE19188, 0.9584 (p<0.0001; sensitivity, 92.00%; specificity, 96.00%) in GSE27262, and 0.9574 (p<0.0001; sensitivity, 95.89%; specificity, 87.67%) in patients from Union Hospital. As for lung squamous cell carcinoma (LUSC), the AUC of PCAT6 was 0.9567 (p<0.0001; sensitivity, 100%; specificity, 85.71%) in GSE30219, 0.9795 (p<0.0001; sensitivity, 96.30%; specificity, 92.31%) in GSE19188, and 0.9942 (p<0.0001; sensitivity, 100%; specificity, 98.04%) in patients from Union Hospital. We further noticed that the plasma levels of PCAT6 were significantly increased in 73 LUAD and 51 LUSC patients compared with 39 healthy controls (p<0.0001). The AUC of circulating PCAT6 was 0.9213 (p<0.0001; sensitivity, 87.67%; specificity, 97.44%) in LUAD and 0.9583 (p<0.0001; sensitivity, 94.12%; specificity, 100%) in LUSC. Together with our previous findings, our results suggest that PCAT6 could be used as a potential diagnostic and prognostic biomarker in NSCLC.