CD34 and myelodysplastic syndrome: CD34, a highly specific surface marker, is widely expressed on early hematopoietic stem/progenitor cells and is vital for their identification, isolation, and investigation [12] Aberrant proliferation, differentiation defects, or apoptotic imbalance in CD34+ cells are considered pivotal in the pathogenesis of MDS, directly correlating with abnormalities in bone marrow hematopoiesis and the diversity of disease phenotypes.