Mesenchimal Stroma Cells From Patients with Myelodysplastic Syndrome and Acute Myeloid Leukemia Show Distinct Cytogenetic and DNA-Mutation Data as Compared with Bone Marrow Leukemic Blasts.

Abstract 4697

Bone marrow mesenchymal stroma cells (BMSC) are key components of the hematopoietic microenvironment. BMSC from patients with acute myeloid leukemia (AML) and myelodisplasic syndrome (MDS) display functional and quantitative alterations. To gain insight into these questions, we carried out cytogenetic analyses, FISH, FLT3 and NPM1 mutation examinations of both hematopoietic (HC) and BMSC derived from 53 AML and 54 MDS patients and 35 healthy donors after in vitro culture expansion. Clonal chromosomal aberrations were detectable in BMSC of 12% of patients. Using FISH we have assume that cytogenetic markers in BMSC were always distinct as the aberrations in HC from the same individual. 17% and 12% of AML patients showed FLT3 and NPM1 mutations in HC, respectively. In BMSC, we could not detect mutations of NPM1 and FLT3, independent from the mutation status of HC. For control analysis, BMSC cultures from 35 healthy donors were prepared under the same conditions. BMSC from healthy donors did show normal diploid karyotypes and absence of specific DNA-mutations of NPM1 and FLT3.

Our data indicate that BMSC from MDS and AML patients are not a part of malignant clone and characterized by genetic aberrations. Lack of aberrations as detected in HC and appearance of novel clonal rearrangements in BMSC may suggest enhanced genetic susceptibility and potential involvement of BMSC in the pathogenesis of MDS and AML.