CLINICAL AND BIOLOGICAL CHARACTERISTICS OF MYELODYSPLASTIC SYNDROMES WITH NULISOMY-Y BY FISH

Background and Objective. In the present study we analyzed the inciden ce of nulisomy Y by fluorescence in situ hybridization in a group of 2 4 males diagnosed with myelodysplastic syndromes (MDS). We explored th e relationship between this chromosome abnormality and other clinical and biological disease characteristics. Methods. Loss of chromosome Y was present in 7 out of the 24 males analyzed (29%); the number of cel ls carrying this chromosome aberration ranged between 19% and 90%. Fro m the clinico-biological point of view, the group of patients with nul isomy Y showed a higher incidence of RA and RAS FAB subtypes (p=0.04), a lower WBC count (p=0.04), a lower proportion of blast cells both in PB (p=0.009) and BM (p=0.06) associated with a decreased myeloid/eryt hroid ratio (p=0.01). Results. No clear association was detected betwe en loss of chromosome Y and other numerical chromosome abnormalities i nvolving chromosomes 7 and 8. In contrast, 2 out of the 7 cases with l oss of chromosome Y also displayed monosomy 1 by FISH. However, the us e of appropriate dual stainings showed that these two abnormalities we re present in different cell populations (that is, they never coexiste d in the same cell population), which supports the notion of the exist ence of clonal heterogeneity in MDS patients. Interpretation and Concl usions. From the prognostic point of view, MDS patients with loss of c hromosome Y displayed a higher survival rate, although these differenc es did not reach statistical significance. (C) 1997, Ferrata Storti Fo undation.