The role of apoptosis in the pathogenesis of the myelodysplastic syndromes

The paradoxical occurrence of peripheral cytopenias despite a normo/hyperce llular marrow in myelodysplastic syndromes (MDS) has been attributed to exc essive intramedullary hematopoietic cell apoptosis. It has also been postul ated that abrogation of programmed cell death (PCD) may underlie MDS transf ormation to acute myeloid leukemia (AML). Despite overwhelming evidence for a role of aberrant apoptosis in myelodysplasia, the molecular mechanisms r esponsible for such changes have not been elucidated. This paper summarizes current evidence implicating a role for altered PCD in MDS and outlines po tential cellular mechanisms whereby hematopoietic progenitor cell apoptosis may be dysregulated. Int J Hematol. 2001:73:416-428. (C) 2001 The Japanese Society of Hematology.