Epidemiological study, immunohistochemistry and in situ hybridization studies of nasopharyngeal carcinomas: a Tunisian report.

ABSTRACT

Nasopharyngeal carcinomas (NPC) are a significant problem of public health in Tunisia. They are particular because of their characteristic geographic distribution. The aims of this study were, first, to appreciate the presence of Epstein-Barr virus (EBV) genome by immunohistochemistry (IHC) and in situ hybridization (ISH) and to compare their benefits to NPC diagnosis and, secondly, to verify the relation between NPC and factors bound to the food and environment conditions. Biopsies, recruited at the department of pathology of EPS Charles Nicolle at Tunis, were analyzed for EBV genome presence by ISH of EBV-encoded small RNA1 (EBER1). IHC was done with encoded nuclear antigen (EBNA1), latent membrane proteins (LMP1), and antigen BZ1 anti-Z EBV-replication activator (ZEBRA). An epidemiological study based upon the analysis of a detailed questionnaire submitted to patients (all from the north of Tunisia) and 60 witnesses was done. The statistic analysis was realised by SPSS Windows 11.5 Advanced Statistics. All samples were classified as Undifferentiated Carcinoma of Nasopharyngeal type (UCNT). We found a sex ratio of 2 with a bimodal repartition. ISH showed 96.6% positive samples. IHC revealed the EBV in 90% of cases and 66.7%, respectively, with EBNA1 and LMP1. The statistic analysis showed a meaningful relation (P<0.05, OR>3) between NPC and dietary factors (spices and piquant condiment), alcohol and the water quality.