The myelodysplastic syndromes.
The myelodysplastic syndromes constitute a fascinating model for monoclonal premalignant disorders. Haemopoiesis is 'dysplastic' with inefficient maturation of a slowly expanding or sometimes of a stable population, of blood cell precursors. About one third of the patients evolve into acute leukaemia, the result of either a progressive expansion of the original clone or a new mutation producing a more malignant subclone. The majority of patients suffer from the results of bone-marrow insufficiency, with pancytopenia and possibly immune deficiency. Characteristic karyotype anomalies involving mainly chromosomes 5, 7 and 8 are seen in half the patients. These same chromosomes are known to carry different oncogenes. The myelodysplastic syndrome occurs mainly in the aged and there is a moderate male preponderance. The incidence is still unknown but is probably similar to that of acute leukaemia. The etiology is also unknown; however, a secondary myelodysplastic syndrome precedes acute myeloid leukaemia, as a late consequence of chemo- and radio-therapy in treated Hodgkin's disease. This suggests that environmental mutagens might also be involved in primary myelodysplastic syndromes. Treatment remains highly unsatisfactory but a few recent developments improve prognosis, at least in the younger patient.
Verwilghen
R L
RL
Department of Haematology, University Hospital, Leuven, Belgium.
Boogaerts
M A
MA
D006801:Humans; D009190:Myelodysplastic Syndromes / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy