Leukaemogenesis in Down's syndrome.

Due to the fixed karyotype and documented malignancy risk in patients with Down's syndrome, recently described aetiological factors can be assigned to their proper places in a conceptual framework for leukaemogenesis in these individuals. This is a more profitable approach than those in which various types of karyotypic patterns are matched to different malignancies. It seems that viruses may play a special role, but they need interaction with other factors, most of which are present in Down's syndrome. A unifying concept which may be helpful in establishing research priorities is presented.