DETECTION OF EPSTEIN-BARR VIRUS GENOME IN ORAL CAVITY SQUAMOUS CELL CARCINOMA SAMPLES OF RUSSIAN PATIENTS

Introduction. Oral cavity squamous cell carcinoma (OC-SCC) is the most common and aggressive malignancy of the oral cavity. Recent studies have revealed infections with human papilloma virus (HPV) as an additional risk factor for oral squamous cell carcinoma development, while distinguished role of Epstein-Barr virus (EBV) remains still uncertain. However, the evidence for association between virus infection and risk of oral squamous cell carcinoma is controversially and varies significantly by geographic regions and race. Purpose. The aim of the present study was to elucidate the prevalence of HPV and EBV in OC-SCC samples of Russian patients from Moscow region. Material and methods. We investigated fresh-frozen tumor tissue fragments obtained from 11 patients with OC-SCC. DNA was extracted and the viral genome was examined by quantitative PCR assays with highrisk type-specific HPV and EBV specific markers followed by sequencing-based analysis. Results. No HPV infection in analyzed OC-SCC samples was observed, while EBV was identified in 70.0% (7/10) of patients. Further based on Q-PCR amplification of the EBV targets including BamHI-W, EBNA1 and C-terminal fragment of LMP1 gene, EBV infection and measurement of virus load in the tumor samples was assessed. Sequencing LMP1-positive products revealed that the most samples (5/6) contained variants LMP1 with Cao deletion characterized by an increased transforming potential. Conclusion. These data suggest that prevalence of EBV infections is common and may influence cancer development, although detected LMP1 variants of EBV are not necessarily associated with the pathogenesis of OC-SCC. Further studies are necessary to determine the potential role of EBV and its possible importance as an infection factor in OC-SCC.