DETECTION OF TRISOMY-8 BY FLUORESCENCE IN-SITU HYBRIDIZATION ON BONE-MARROW SMEARS FROM PATIENTS WITH SUBTLE MYELODYSPLASTIC CHANGES

Trisomy 8 is the most common hyperdiploid numerical chromosomal abnorm ality that is found in myelodysplastic syndromes (MDSs). We explored t he utility of combining fluorescence in situ hybridization interphase cytogenetics with routine morphologic analysis to characterize cases f or which signs and symptoms were suggestive of MDS in which dysplastic changes were insufficient for a definitive diagnosis. Hybridization w ith a chromosome 8-specific centromeric probe was performed on bone ma rrow smears that were obtained from four patients with cytogenetically documented trisomy 8 and hematopoietic cell atypia that was suggestiv e but not diagnostic of MDS. Signals that corresponded to trisomy 8 we re detected in 14.6% to 32.2% of the cells (detection threshold of tri somic clone, 5.0%). The conditions of two patients have remained hemat ologically stable with no disease progression, and these two patients are now considered to have refractory anemia. The conditions of the ot her two patients rapidly progressed to morphologically recognizable MD Ss. This study demonstrates that the detection of trisomy 8 by fluores cence in situ hybridization can provide useful supplemental informatio n in bone marrow specimens with morphologic changes that are suggestiv e of but not sufficient for a diagnosis of MDS. It should prove to be useful when standard cytogenetic analysis has not been performed or wh en it is not readily available.