Abstract
Background: Long intergenic non-coding RNA, regulator of reprogramming (LINC-ROR) is a newly identified cytoplasmic long non-coding RNA (lncRNA), which has been found to be dysregulated in different cancers. The present work aimed to quantify LINC-ROR expression profile and assess the tumor proteins p53 and caspase 3 expressions in glioblastoma tissue specimens compared to non-cancer tissues, and to correlate these expression levels with the available clinicopathological and survival data. Methods: LINC-ROR relative expression in 57 glioblastoma cancer tissues and 10 non-cancer tissues was quantified by real-time polymerase chain reaction (qPCR). In addition, methylation-specific PCR of O-6-methylguanine-DNA methyltransferase (MGMT) promoter and immunohistochemical expression of apoptosis related proteins: p53 and caspase 3 were performed. Results: The up-regulation of LINC-ROR was encountered in 89.5% of patients. The higher expression of LINC-ROR was associated with poor disease progression-free and overall survival as well as a younger age of patients (P=0.036). p53 protein was expressed only in glioblastoma but not in non-cancer tissues while caspase 3 was weakly expressed in most non-cancer tissues and in varying degrees in glioblastoma (24% weak, 30% moderate, and 16% strong expression). The Kaplan-Meier survival plot illustrated poor survival in glioblastoma patients with over-expressed LINC-ROR (P=0.010) and down-regulated p53 (P=0.002). Multivariate analysis showed that glioblastoma patients were clustered into two distinct groups based on LINC-ROR expression profile, p53 staining levels and patients' overall survival. Conclusions: LINC-ROR up-regulation may have a role in glioblastoma tumorigenesis and could be a potential prognostic marker for this fatal disease.