CHARACTERIZATION OF A T(10-12)(Q24-P13) IN A CASE OF CML IN TRANSFORMATION

We have used Southern blotting and fluorescence in situ hybridization (FISH) to define the breakpoints of a reciprocal translocation, t(10;1 2)(q24;p13), acquired as a secondary abnormality in a patient with Phi ladelphia chromosome positive chronic myeloid leukemia (CML) in transf ormation. A YAC clone that spanned the breakpoint at 12p13 was identif ied; this YAC included the CDKN1B gene but did not include ETV6. Neith er ETV6 nor CDKN1B was rearranged, as determined by FISH and Southern blotting; however, a small deletion encompassing the translocated CDKN 1B allele was detected. Analysis of two candidate genes at 10q24, HOX1 1 and NFKB2 suggested that they are not involved in this translocation . The preliminary mapping of breakpoints in this case demonstrated tha t they are different from an apparently identical translocation identi fied previously in a patient with myelodysplastic syndrome. The identi fication of the split YAC and small deletion should enable a more focu sed search for a gene or genes that may contribute to progression from chronic phase to blast crisis in CML. (C) 1997 Wiley-Liss, Inc.