Comparative epidemiological studies have for a long time suggested a link (or links) between infectious agents and hematological malignancies in the young.

Identification of Epstein-Barr virus (EBV) as the major cause of specific subtypes of Burkitt's lymphoma and Hodgkin's disease 20 and 10 years ago, respectively, and the recent involvement of human T-cell leukemia virus in non-Hodgkin's lymphomas of the T-cell lineage in young adults in Jamaica have given further credit to early presumptions that these diseases have an infectious etiology.

The spectrum of possibly involved viruses : old, EBV, and new, herpesviruses 6,7 and 8, and unknown retroviruses - as well as the list of partially or totally unresolved disease entities : Hodgkin's disease in adolescents, non-Hodgkin's lymphomas in the immunocompromised, and acute lymphocytic leukemia - is rapidly expanding.

Both direct and indirect transforming effects of the above-mentioned viruses are being rapidly disclosed.

However, the complex interaction between the different viruses and other causes of hematological malignancies in the young guarantees that many things remain to be discovered also in the future.