ABSTRACT
Mesenchymal stromal cells (MSCs) are an essential cell type of the hematopoietic microenvironment. Concerns have been raised about the possibility that MSCs undergo malignant transformation. Several studies, including one from our own group, have shown the presence of cytogenetic abnormalities in MSCs from leukemia patients. The aim of the present study was to compare genetic aberrations in hematopoietic cells (HCs) and MSCs of myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) patients. Cytogenetic aberrations were detected in HCs from 25 of 51 AML patients (49%) and 16 of 43 MDS patients (37%). Mutations of the FLT3 and NPM1 genes were detected in leukemic blasts in 12 (23%) and 8 (16%) AML patients, respectively. Chromosomal aberrations in MSCs were detected in 15 of 94 MDS/AML patients (16%). No chromosomal abnormalities were identified in MSCs of 36 healthy subjects. We demonstrate herein that MSCs have distinct genetic abnormalities compared with leukemic blasts. We also analyzed the main characteristics of patients with MSCs carrying chromosomal aberrations. In view of these data, the genetic alterations in MSCs may constitute a particular mechanism of leukemogenesis.
Subject(s)
Chromosome Aberrations , Leukemia, Myeloid, Acute/genetics , Leukemia, Myeloid, Acute/pathology , Mesenchymal Stem Cells/pathology , Myelodysplastic Syndromes/genetics , Myelodysplastic Syndromes/pathology , Abnormal Karyotype , Adult , Aged , Aged, 80 and over , Cell Transformation, Neoplastic/genetics , Chromosomes, Human, Pair 11 , Chromosomes, Human, Pair 19 , Female , Hematopoietic Stem Cells/pathology , Hematopoietic Stem Cells/physiology , Humans , Leukemia, Myeloid, Acute/mortality , Male , Mesenchymal Stem Cells/physiology , Middle Aged , Myelodysplastic Syndromes/mortality , Nuclear Proteins/genetics , Nucleophosmin , Young Adult , fms-Like Tyrosine Kinase 3/geneticsABSTRACT
OBJECTIVE: Bone marrow mesenchymal stroma cells (BMSC) are key components of the hematopoietic microenvironment. The question of whether BMSC from patients with hematological disorders have cytogenetic abnormalities is discussed controversially, some studies indicating that they are cytogenetically normal and others providing evidence of their aberrations. PATIENTS AND METHODS: We performed standard and molecular cytogenetic analyses of both hematopoietic cells and BMSC from 31 patients with myelodysplastic syndrome (MDS, n = 18) and acute myeloid leukemia (AML, n = 13) and 7 healthy individuals. Mononuclear cells were isolated from fresh bone marrow aspirates at the time of initial diagnosis for cytogenetic analysis of hematopoietic cells (HC) and selection of BMSC. RESULTS: Clonal cytogenetic aberrations were observed in HC from 8 (44%) MDS and 8 (61%) AML patients. Cytogenetic analyses of BMSC were successfully performed in 27 of the 31 cases. Structural chromosomal aberrations, including t(1;7), t(4;7), t(7;9), t(7;10), t(7;19), t(15;17), and others, were detectable in BMSC from 7 of 16 (44%) MDS and 6 of 11 (54%) AML patients. The breakpoints of chromosomes in BMSC were typical for leukemia aberrations. Two patients showed clonal chromosomal markers. CONCLUSIONS: BMSC from MDS and AML patients show chromosomal abnormalities. Although the majority of cytogenetic aberrations in BMSC were not clonal and differed from chromosomal markers in HC from the same individual, detection of typical chromosomal changes in BMSC suggests enhanced genetic susceptibility of these cells in MDS/AML. This may indicate potential involvement of BMSC in the pathophysiology of MDS/AML.
