Clinical implications of fluorescence in situ hybridization analysis in 13chronic myeloid leukemia cases: Ph-negative and variant Ph-positive

Thirteen chronic myeloid leukemia (CML) patients, 10 with variant Philadelp hia (Ph) translocations and 3 Ph negative cases, were analyzed by fluoresce nce in situ hybridization (FISH) with the use of BCR and ABL cosmid probes and a chromosome 22 painting probe. In the variant Ph translocations, the B CR-ABL fusion gene was located on the Ph chromosome; in 1 CML Ph-negative p atient, the BCR-ABL fusion gene was located on the Ph chromosome; and, in 2 patients, if was located on chromosome 9. The chromosome 22 painting probe was detected on the third-party chromosome of the variant translocation, a nd in none of the variant translocations was there any detectable signal on chromosome 9. In CML patients with clonal evolution of a simple Ph, a sign al of the chromosome 22 painting probe was detected on the der(9) of the Ph translocation. If was concluded that the variant Ph translocations evolved simultaneously in a three-way rearrangement. The clinical parameters of th e 13 patients were similar to chose of a large group of CML patients with a simple Ph translocation. If is suggested that, to determine the prognosis of CML patients with a complex karyotype, FISH analysis with a chromosome 2 2 painting probe be performed. (C) Elsevier Science Inc., 1999. All rights reserved.