Epstein-Barr Virus Latent Membrane Protein-1 Expression in Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC), a malignant neoplasm of the epithelium covering the nasopharynx, is a rare disease in most parts of the world. Epstein-Barr virus (EBV), the most potent oncogenic virus, coupled with environmental and genetic factors has been identified to play a role in the development of NPC. An array of methods for detecting the virus do exist, from serologic detection of antibodies to DNA amplification. There is paucity of local data on the status of EBV infection in relation to NPC within the region, and this study attempts to shed more light on the subject.

This was a retrospective cross-sectional laboratory-based study on histologically confirmed, archived tissues from July 2015 to June 2019. Immunohistochemistry expression of latent membrane protein-1 (LMP-1) was used to detect EBV infection in the tissues.

A total of 71 cases were enrolled in this study. The mean age was 47.87 years ± 16.84 years with a male-to-female ratio of 1.5:1. There was a unimodal distribution of EBV detection, with the peak (26.8%) at 36-45 years. About 45.1% of the 71 samples tested positive for LMP-1, all of which were nonkeratinizing carcinoma. Nonkeratinizing carcinoma was the most common histopathologic subtype (n = 67; 94.4%), with the majority (38 of 67; 56.7%) being undifferentiated and 29 of 67 (43.3%) differentiated. Keratinizing and basaloid subtypes had two cases each, representing 2.8%.

A significant proportion of NPC, particularly nonkeratinizing histologic subtype, seems to show LMP-1 positivity by immunohistochemistry, which may be adopted in resource-constrained settings to detect EBV infection in these tissue biopsies.