Aetiology of nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC), a rare tumour in most parts of the world, occurs in high frequencies in China and South East Asia and is particularly high among the Southern Chinese. In certain parts of China the incidence may reach 50 per 10(5) per year while in most other ethnic groups the incidence is very low, e.g. among Caucasians the incidence is less than 1 per 10(5) per year. These marked geographic and racial differences in incidence have stimulated much research into the aetiology of this cancer. Potential aetiological factors will have to explain this 50-100 fold difference in incidence. Both genetic and various environmental factors have been postulated. This paper discusses the role of the Histocompatibility Locus Antigen (HLA), Epstein Barr Virus and chemical carcinogen including salted fish in the development of NPC.