THE ASSOCIATION OF SQUAMOUS-CELL CARCINOMAS OF THE NASOPHARYNX WITH EPSTEIN-BARR-VIRUS SHOWS GEOGRAPHICAL VARIATION REMINISCENT OF BURKITTS-LYMPHOMA

Nasopharyngeal carcinoma (NPC) is rare in most parts of the world but occurs with high incidence in cen tain regions, such as South-East Asi a. Two major histological types of NPC are recognized, non-keratinizin g carcinoma and squamous cell carcinoma. Non-keratinizing NPCs, which include undifferentiated NPC, are invariably associated with Epstein-B arr virus (EBV) infection, regardless of the geographical or ethnic or igin of the patients. By contrast, conflicting results have been publi shed concerning a possible association of squamous cell NPC with the v irus, To address this question, squamous cell NPCs have been collated from an area where NPC is endemic, Hong Kong, and from two regions whe re NPC occurs with a lower incidence, Chengdu, PR China, and Birmingha m, United Kingdom. lit sito hybridization for the detection of the sma ll EBV-encoded nuclear RNAs (EBERs) demonstrated that all 22 cases fro m Hong Kong were EBV-positive. By contrast, EBV was detectable in 7 of 19 cases from central China, and in 3 of 7 casts from the U.K. Expres sion of the virus-encoded latent membrane protein 1 (LMP1) was detecte d in 3 of 32 EBV-positive squamous cell NPCs. These results indicate t hat the association of squamous cell NPCs with EBV shows geographical variability in a manner which is reminiscent of the situation encounte red in Burkitt's lymphoma. This suggests that squamous cell NPCs are a pathogenetically heterogeneous group of tumours distinct from non-ker atinizing NPCs. (C) 1997 John Wiley & Sons, Ltd.