Environmental, genetic and viral risk factors of nasopharyngeal carcinoma in North Africa

NPC (Nasopharyngeal carcinoma) is a tumour that arises in the epithelium surface of the posterior nasopharynx and shows a peculiar geographic and ethnic distribution. Intermediate incidence (8-12 cases/100,000/ year) was reported in the North African population (710% of all cancers among men), where NPC is also the commonest tumour of the ear, nose and throat region. In Asia, the majority of the cases occur in the fifth and sixth decades of life. In contrast, in North Africa the age distribution is bimodal with a minor peak in people aged between 10 and 25 years old. This juvenile form accounts for approximately 20% of the patients and has specific clinical and biological features. Geographical correlation was also observed between percentages of young cases and consanguinity rates over endemic and non-endemic populations, which may therefore explain the shape of the age curve in North Africa. Regardless of its incidence and geographic distribution, NPC results from the contribution of environmental, genetic and viral factors. These factors might however combine differently for Asian and North African patients and also among North African patients of the two age groups.