CD34 and myelodysplastic syndrome: These characteristics do not only mark genetic instability in CD34+ cells but may indicate malignant transformation: (i) γH2AX foci increase across the spectrum from myelodysplastic syndromes (MDS) to AML [50], (ii) centrosome aberrations occur during transformation of MDS [51] and correlate with the cytogenetic risk profile of AML [52] and (iii) complex aberrant karyotypes are an adverse prognostic factor in AML [53].