Immunohistochemical study of the prevalence of EBV- antigen in nasopharyngeal carcinoma

ABSTRACT

A broad range of neoplasms can arise in the nasopharynx derived from epithelial, lymphoid, mesechymal, neurogenic, and rarely from embryonic remnant. These tumours have a long latent period with few primary symptoms which often lead to delay in there diagnosis. This retrospective study was designed for highlighting the challenges involved with the recognition of the nature of nasopharyngeal carcinoma, their classification, and correlation of the available clinical data with histopathological and immunohistochemical diagnosis and the prevalence of EBV infection among the studied cases of NPC. The present work was carried out on 23 cases referred as biopsy from nasopharyngeal tumour to Pathology Department, Faculty of Medicine Tanta university, Tanta Cancer center, the private laboratory during the last five years started from January 2002.and ended on December 2006 .Tissue specimens were all obtained by bunch and excision biopsy. Available clinical data were tabulated and analysed. All cases were subjected to routine histopathological examination and immunohistochemical study for EBV-LMP1. In the present study UNPC was more common [69.6%] than keratinizing NPC [30,4%]. The former occurred in younger patient [9/16], meanwhile the latter occurred in older individuals [5/7], NPC was common in male [60.9%] and bimodal distributions of cases were detected. The diagnosis of UNPC in most cases could be established through the presence of atypical epithelial cells and the lack of cytological atypia among reactive lymphocytes, as well as by immunohistochemical examination for EBV-LMP1. In the present study IHC was employed on paraffin embedded specimens of all the studied cases of NPC using of EBV-LMP1 reactivity. Accordingly, it was found that positive strong cytoplasmic and /or membranous immunorectivity for EBV-LMP1 was evident in [69.6%] of the total cases of NPC, while [23.4%] were negative. Positive cases included [57.2%] of keratinizing NPC, and [75%] of UNPC, meanwhile negative immunostaining for EBV-LMP1 was seen in the remaining [42.8%] of keratinizing NPC and the remaining [25%] of UNPC. The overall association of EBV-LMP1 immunoreactivity with NPC was found to be statistically significant with higher percentage of positive association among UNPC cases. Correlation of EBV-LMP1 immunoreactivity with age and .gender among cases of NPC was found to be statistically insignificant