HIDDEN MONOSOMY-7 IN ACUTE MYELOID-LEUKEMIA AND MYELODYSPLASTIC SYNDROME DETECTED BY INTERPHASE FLUORESCENCE IN-SITU HYBRIDIZATION

Fifty patients [25 acute myeloid leukemia (AML) and 25 myelodysplastic syndrome (MDS)], without monosomy 7 according to conventional cytogen etics, were re-examined by fluorescence in situ hybridization (FISH). Eleven (44.0%) patients with AML and nine (36.0%) with MDS showed hidd en monosomy 7. Two samples who had both monosomy 7 and iso chromosome 17 were analyzed by dual color FISH to identify their clonal origin, a nd showed that these two abnormalities can occur together or independe ntly. Only one of 16 MDS patients without monosomy 7 transformed into AML whereas four of eight MDS patients with the hidden monosomy 7 tran sformed into AML, suggesting patients with this abnormality are more l ikely to undergo transformation to AML. Copyright (C) 1996 Elsevier Sc ience Ltd.