Expression of H19 long non-coding RNA is down-regulated in oral squamous cell carcinoma

Long non-coding RNAs (lncRNAs) are a group of non-protein-coding RNAs which are longer than 200 nucleotides. LncRNAs play important roles in epigenetic modification, transcription and post-transcriptional regulation, maintenance of normal tissue development and differentiation. LncRNA could serve as a biomarker for diagnosis and prognosis as well as a molecular target for therapy in oral squamous cell carcinoma (OSCC). Therefore, we have determined the expression profile of 5-lncRNAs namely UCA1, TUG1, HOTAIR, MALAT1, and H19 by quantitative real-time PCR in tumor tissues and adjacent normal tissue of 32 OSCC patients. To determine the expression, methylation status and genomic alterations in lncRNAs across pan-cancer, TCGA datasets were analyzed by UALCAN, MEXPRESS and cBioPortal database. Then, we determined the association between lncRNA expression and clinicopathological attributes of patients by Spearman's rank test. Expression of UCA1 and TUG1 genes was up-regulated in 54.83% and 53.12% OSCC tumors, respectively. Importantly, expression of MALAT1 and H19 was down-regulated in tumor tissues of 62.5% and 81.25% respectively of OSCC patients. Except for MALAT1, our experimental data showed concordance with the TCGA analysis. Expression of HOTAIR in OSCC tumors was positively correlated with tumor volume, whereas MALAT1 and H19 negatively correlated with the smoking status of patients.