Tyrosine kinases activated by mutation or translocation are involved in the chronic phase of myeloproliferative disorders. Complementary or alternative events are not so well characterized. We report here a case of t(8;13) generating a ZNF198-FGFR1 fusion kinase gene on the derivative chromosome 13. ZNF198-FGFR1 mRNA, but not FGFR1-ZNF198, was detected by polymerase chain reaction amplification. By using fluorescence in situ hybridization with BAC clones, we mapped a deletion of about 2 megabases on the derivative chromosome 8, including the reciprocal FGFR1-ZNF198 fusion gene and the surrounding genes from 8p11 and 13q12. Potential tumor suppressor genes affected by the deletion by loss (IFT88, CRYL1, TACC1) or break (LATS2) may participate in the malignant process.