FAS and myelodysplastic syndrome: [2, 3] We have previously reported that CD95 is overexpressed on CD34+ progenitors and erythroblasts in two thirds of patients with lower risk myelodysplastic syndromes (MDS), a clonal disorder of the hematopoietic stem cell (HSC) that evolves to acute myeloid leukemia (AML) in 30% of cases.