CD34+ cell selection is required to assess HOXA9 expression levels in patients with myelodysplastic syndrome.

Overexpression of HOXA9 is linked to the molecular pathogenesis of acute myeloid leukaemia (AML) and myelodysplastic syndrome (MDS), conferring a poor prognosis. HOXA9 expression levels were analysed in the diagnostic bone marrow (BM) samples of 13 MDS patients. HOXA9 was expressed by CD34(+) BM cells at median levels 3.1-fold higher than in CD34(-) cells from the same patient and at median levels 4.3-fold higher than in CD34(+) cells from healthy donors. These results indicate that CD34(+) cell selection is required to accurately assess the expression levels of HOXA9 and related genes in the multipotential malignant progenitor cells of MDS patients.