Chromosomal Aberrations Characteristic for sAML/sMDS Are Not Detectable by Random Screening Using FISH in Peripheral Blood-Derived Grafts Used for Autologous Transplantation

Acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) is observed in 5 to 10% of patients treated with high-dose chemotherapies followed by autologous stem cell and bone marrow transplantation. Both diseases are frequently associated with monosomy 7 (-7), trisomy 8 (+8), loss of the long arm of chromosome 5 (-5q), and deletions including the TP53-gene region according to del(17)(p13). In this study, we examined whether these chromosomal aberrations are already detectable in blood stem cells from patients who have all been treated with standard chemotherapies prior to peripheral blood stem cell transplantation (PBSCT). Therefore, we screened peripheral blood derived stem cells obtained at the time of stem cell harvest for the presence of -7, +8, -5q, and del(17)(p13) by fluorescence in situ hybridization (FISH). Our series included 40 patients: 4 patients with Hodgkin's disease, 6 patients with non-Hodgkin-lymphoma (NHL), 1 patient with ALL, 4 patients with plasmocytoma, and 25 patients with solid tumors. Peripheral blood mononuclear cells (PBMC) from eight healthy blood donors served as controls. Assuming a hybridization efficiency of >98%, the cut-off level of non diploid cells was determined for each DNA-probe. None of the stem cell preparations exhibited chromosomal damage. Our findings indicate that chromosomal damage is a rare event in stem cell autografts.