Tumor-derived exosomal lncRNA GAS5 as a biomarker for early-stage non-small-cell lung cancer diagnosis

Diagnosis and treatment at an early stage may improve survival of non-small-cell lung cancer (NSCLC). Previous studies have found that long noncoding RNA growth arrest-specific transcript 5 (GAS5) is essential to cancer progression. However, the expression and diagnostic value of GAS5 in exosomes (Exo-GAS5) remain unclear. One hundred and four participants were enrolled, including subjects with NSCLC (n=64) and healthy subjects (n=40). The total Exosome Isolation Kit was applied to isolate exosomes from serum. Total RNA was extracted and the AS5 expression was analyzed using quantitative reverse transcription polymerase chain reaction. Receiver operating characteristic (ROC) curve analysis was applied to evaluate the diagnostic value of Exo-GAS5 in NSCLC. Our data indicated that the Exo-GAS5 was downregulated in patients with NSCLC compared with healthy controls (p<0.001). Furthermore, patients with NSCLC with larger tumor size (p=0.025) and advanced TNM (T: extent of the primary tumor; N: lymph node involvement; M: metastatic disease) classification (p=0.047) showed lower Exo-GAS5 expression. ROC curve analysis using Exo-GAS5 combined with carcinoembryonic antigen showed an area under curve (AUC) of 0.929. Exo-GAS5 could be used to distinguish patients with Stage I NSCLC with an AUC of 0.822. In conclusion, Exo-GAS5 may function as an ideal noninvasive serum-based marker for identifying patients with early NSCLC.