Background: Accumulating evidence reveals that long non-coding RNAs (lncRNAs) play a crucial role in pathogenesis of non-small-cell lung cancer (NSCLC), providing a new concept to exploit novel biomarkers for diagnosis, prognosis or therapeutic target of NSCLC. The intention of this study was to examine the viability of lncRNA PRAL as a biomarker for NSCLC and explore its biological function in NSCLC cell lines.
Methods: PRAL transcription levels were evaluated using Q-PCR. Receiver operating characteristic (ROC) curve analyses were used to evaluate the diagnostic value for NSCLC patients. Kaplan-Meier analysis and log-rank test were performed to assess the correlation between PRAL expression and the clinical outcomes on overall survival (OS) and progression-free survival (PFS).
Results: PRAL expression levels were prominently decreased in a majority of the NSCLC tumor tissues compared with corresponding adjacent normal tissues (p < 0.0001) and healthy tissues (p < 0.0001). Receiver operating characteristic (ROC) curve analyses indicated strong separation between the NSCLC tissues and the control group, with an AUC of 0.8546 (95% CI: 0.7993 to 0.9098; p < 0.0001) for PRAL. Using the Chi-square test showed an obvious negative correlation between down-regulated PRAL levels and advanced TNM stage (χ2 = 8.826, p = 0.003). High PRAL levels had a longer median OS and median PFS (median OS, 42 months vs. 33.5 months, p = 0.0122; median PFS, 30 months vs. 24.5 months, p = 0.0317). Univariate and multivariate analysis of clinical pathological factors were also performed. In addition, over-expression of PRAL blocked proliferation，migration, and invasion in NSCLC cell lines.
Conclusions: Taking these results together, PRAL expression level could be a potential biomarker for diagnosis in NSCLC patients.