Molecular Grading of Oral Squamous Cell Carcinomas Infected with EBV

Abstract

Background: Squamous Cell Carcinoma (SCC) is a type of cancer that is often found in oral cavity and areas of<br />the head and neck. Viruses are major etiological factors through production of factors that can disturb proliferation<br />and apoptosis regulators such as p53i, c-myc and bcl-2. This study aimed to determine the molecular grading of oral<br />squamous cell carcinoma (OSCCs) infected with the Epstein-Barr Virus (EBV). Methods: Twenty-seven OSCC patients<br />underwent biopsy to detect EBV infection through in situ hybridization for RNA EBV (EBER) and immunohistochemical<br />analysis of latent membrane protein-1 (LMP-1) and EBV nuclear antigen-1 (EBNA-1). To assess molecular grades, cell<br />proliferation and apoptosis regulator expression i.e. inactive p53 (p53i), c-myc and bcl-2, were immunohistochemically<br />analysed. Results: The cases were divided into two groups; infected and non-infected by EBV. Regression analysis<br />showed that only EBNA-1 expression could affect p53i expression. Based on regression equations molecular grading of<br />OSCCs infected by EBV was divided into three: Grade I (low), EBNA-1 expression was 7.60, and p53i expression<br />was 9.74-17.5; Grade II (medium), EBNA-1 expression was 7.61-19.7, and p53i 17.5-30.1; Grade III (high), EBNA-1<br />expression was 19.71, and p53i ≥ 30.1. Conclusion: In OSCC infected with EBV, only EBNA-1 expression can<br />influence p53i expression.