Determination of the Expression of Latent Epstein Barr Virus in Omani Nasopharyngeal Carcinoma Patients

Abstract

Nasopharyngeal carcinoma(NPC) is a rare malignant carcinoma that develops in the epithelial lining of the nasopharyngeal mucosa. It is the most common neoplasm of the Nasopharynx and it is associated with many risk factors; one of them is Epstein-Barr virus infection. An Epstein-Barr virus is a tumorigenic herpes virus that infects and persists in B-lymphocytes without causing disease. This virus is associated with significant pathological conditions, such as benign and malignant lymphoproliferation. The aim of the present study is to determine Epstein -Barr encoded RNA 1&2 (EBER1,2) and latent membrane protein (LMP) expression in formalin-fixed paraffin-embedded tissue samples obtained from Omani patients diagnosed with nasopharyngeal carcinoma. Also, to identify the pattern and the type(s) of cells infected with EBV in nasopharyngeal carcinoma tissue samples obtained from Omani patients. Moreover, to compare the sensitivity of Immunohistochemistry and in-situ Hybridization for the detection of EBV in the nasopharyngeal carcinoma tissue sample. Thirteen formalin-fixed paraffin-embedded nasopharyngeal carcinoma tissue samples archived from the period 2010 to 2017, were obtained from the Pathology Departments of Sultan Qaboos University Hospital and the Armed Force Hospital. These tissue samples were processed using two different methods Immunohistochemistry (IHC) and In situ hybridization (ISH). Eleven out of thirteen NPC Omani patients were positive for EBV (84.61%) by either LMP-IHC or EBER-ISH. All cells stained positive for EBV in NPC tissue samples was of malignant type rather than normal cell type. EBV is mostly detected in patients in the age group of less than 50 years old. Also out of the 13 NPC patients, seven females (58.34%), and six males (46.15%) were positive for EBV. This study may provide evidence indicating an association between EBV and nasopharyngeal carcinoma. In addition, the detection of EBV in NPC obtained from Omani patients may encourage the physician to consider using anti-herpes virus drugs in the treatment of EBV positive NPC patients as an additional tool for the treatment of this kind of malignancy.