ABSTRACT
Oral herpes virus infections are thought to be a responsible predisposing cause of nasopharyngeal cancer. Of the herpes viruses, Epstein-Barr virus [EBV] has classically been associated with nasopharyngeal carcinoma [NPC] and Burkitt's lymphoma. Recently, multiple studies have been published linking EBV with oral squamous cell carcinoma and, to a lesser extent, hypopharyngeal and laryngeal tumors. Using a sensitive method of detection, this study was conducted to analyze the presence of EBV DNA in 40 NPC cases and 35 cases with benign nasal polyps as control in serum and tissue and compared it with serological markers. Three EBV serological markers were performed by enzyme linked immunosorbant assay including EBV VCA IgM, EBV IgG and EBNA IgG. Herpes simplex virus antibodies HSV I and II IgG were examined in serum. Forty serum and tissue samples exclusive of nasopharyngeal carcinoma were examined for the presence of EBV DNA and HSV II DNA using qualitative polymerase chain reaction. Thirty-five serum and tissue samples of benign nasal polyps were submitted to all the tests as control. Serological tests for EBV: revealed that EBV VCA IgG was positive in 57.5%, EBNA IgG was positive in total of 47.5% NPC. EBV DNA was positive in serum in all EBV VCA IgG and EBNA IgG positive cases. EBV DNA by PCR in tissue was positive in 72.5% of NPC in which 70% were EBV-DNA serum positive. In the benign group 17.1% EBV-DNA tissue positive cases, only 2.9% were EBV-DNA serum positive by PCR. HSV DNA in tissue was positive in 20% of NPC and 11.4% of benign group. In NPC HSV-DNA tissue positive cases, 2.5% were HSV-DNA serum positive by PCR and 17.5% were negative. The results indicate that HSV and EBV have a role in the etiology of nasopharyngeal carcinoma. Detection of EBNA1 and HSV in the serum and corresponding tissue of nasopharyngeal carcinoma indicates the role of circulating viral DNA as an early marker for pathogenesis of nasopharyngeal carcinoma and that it could serve as good supplement to pathological diagnosis of nasopharyngeal carcinoma