Abstract :
The leukaemias vary in their response to therapy. In acute myeloid leukaemia, for instance, response to therapy is poorer in older than in younger patients. One explanation for this is that in older patients the acute myeloid leukaemia is more likely to have arisen from a pluripotent stem cell than from a lineage-restricted progenitor cell; the former has a high self-renewal capacity, an active drug-efflux pump, and high content of anti-apoptotic proteins, all of which contribute to chemoresistance. Unravelling the biology of the leukaemias should help in the development of novel therapies.