Fluorescence in situ hybridization analysis of complex translocations in two newly diagnosed Philadelphia chromosome-positive chronic myelogenous leukemia patients

Two different complex translocations from newly diagnosed cases of Philadel phia chromosome-positive chronic myelogenous leukemia (CML) were characteri zed by G-banding and fluorescence in situ hybridization (FISH) analysis. In one case, a unique balanced t(9;22;9;11) (q34;q11;p22;q23) was identified by G-banding, and confirmed by FISH using MBCR/ABL and painting probes. In the second case, an apparently balanced t(19;22) was identified by G-bandin g analysis. FISH using MBCR/ABL probe defected the fusion gene on the deriv ative chromosome 22, indicating the involvement of chromosome 9. Further FI SH analysis with selected painting probes showed that the t(19;22) was a re sult of a complex translocation involving chromosomes 9, 19, 21, and 22. (C ) Elsevier Science Inc., 1999. All rights reserved.