Opportunities for study of lymphoid neoplasia in Africa

Animal models have strongly suggested that lymphoid leukaemias and malignant lymphomas might have a viral etiology. Following the first report by Ludwig Gross in 1951 of the transmission of mouse leukaemia by cell-free filtrates inoculated into newborn mice and the subsequent identification of many tumour-inducing type-C viruses in animals, attention was focused on the RNA retroviruses. However, it was work in Africa which led to the recognition of Burkitt's lymphoma as an entity and to the discovery of the Epstein-Barr virus. Many refer to this DNA virus as the first recognized human tumour virus. The research that these early studies stimulated has resulted in enormous progress in our understanding of human carcinogenesis and in highly significant advances in therapy. More recently, the first human retrovirus was identified and characterized in the laboratory of Dr Robert Gallo. There is increasing evidence that this virus, isolated from a patient with a T-cell lymphoma, is etiologically associated with a specific type of T-cell neoplasm first described in Japan. Africa may be considered the cradle of geographical pathology and the potential for generating unique information on cancer etiology and cancer control is still enormous. Lymphoid neoplasms are excellent models for the study of human cancer, particularly in Africa, since as tumours of the immune system, their induction and evolution is strongly influenced by those environmental factors, such as infection and nutrition, which have a profound effect on the immune response. In addition, there is good evidence that at least some of the tumours in this group are associated with specific transforming viruses. There is an immediate need to collect accurate, reproducible and comparable data on the incidence and characteristics of the different types of lymphoid neoplasia and on the populations in which they occur in the various African countries. Such data will provide the basis for undertaking simultaneous or subsequent etiological and therapeutic studies. Realistic approaches to these goals are considered and specific studies relating to questions posed by available information discussed.