Diverse Expression Patterns of EBV Oncogenes (LMP2A, EBV-Encoded microRNA, and EBV-encoded dUTPase) in EBV Associated Gastric Carcinoma and their Association with Viral Loads.

Abstract

The chromogenic in situ hybridization (CISH) test is the gold standard for detecting Epstein-Barr virus (EBV)-associated gastric carcinoma (GC). Real-time (RT) PCR method is also a sensitive test that can detect the viral load in samples. As such, three EBV oncogenes were investigated in this study. RNA extraction and cDNA synthesis were performed on GC tissues of nine patients, who were previously confirmed to have EBVGC subtype. In addition, 44 patients that had positive RT-PCR but negative CISH results were also included as the control group. TaqMan RT-PCR analysis was performed to determine the expression of EBV-encoded microRNAs, and the expression of EBV-encoded dUTPase, as well as LMP2A, was analyzed by SYBR Green RT-PCR. EBV-encoded microRNAs and LMP2A were identified in 2 out of 9 (22%) EBVGC subtypes. In addition, EBV-encoded dUTPase was detected in 4 out of 9 (44.5%) EBVGC subtypes. EBV-encoded dUTPase was also expressed in a sample of the control group. The expression of LMP2A, EBV-encoded microRNAs, and EBV-encoded dUTPase viral oncogenes in patients with high EBV viral loads indicates that these expressions correlate with viral loads. Our findings indicate that the EBV-encoded dUTPase gene may have a role in EBVGC patients' non-response to treatment and might be considered a Biomarker-targeted therapy.