Childhood cancers and competing causes of death.

From the survey that first identified cancer effects of foetal irradiation and related sources has come support for the following hypotheses: (1) competing causes of death for childhood cancers include abortions (solid tumours) and infections (RES neoplasms); (2) the forms taken by RES neoplasms vary with the nature and intensity of indigenous infections; (3) ideal conditions for developing diffuse RES neoplasms (leukaemia) include the gross immunological incompetence caused by trisomy 21; (4) the unusually localised RES neoplasms found in children who have survived repeated attacks of malaria (Burkitt lymphoma and chloroma) are probably the result of these children having exceptionally high levels of passive as well as active immunity; and (5) when teratogenic effects of in utero mutations include faulty erythropoiesis as well as faulty leucopoiesis, infections are not the only rival causes of death.