MKI67 and myelodysplastic syndrome: In our previous study, the Ki-67 proliferation index of nucleated erythroid cells was shown to be significantly reduced in bone marrow (BM) aspirates from MDS patients (40%) compared to nonmalignant BM (70%), while the interpatient variability in MDS was high.6 These findings indicate that this parameter may be an important factor in the development of transfusion-dependence.