High resolution breakpoints of the Philadelphia translocation in patients with chronic myelogenous leukemia

Abstract

SummaryThe breakpoints of the Philadelphia (Ph) translocation were studied precisely with high resolution chromosome banding in 19 patients with chronic myelogenous leukemia (CML). The cultures were treated with ethidium bromide to obtain elongated and finely banded chromosomes. In five cases chromosomes were examined at 850 bands/haploid set of chromosome stage and the Ph breakpoints were specified on 9q34.11 band and 22ql 1.21 band. The remaining 14 cases revealed the breakpoints on bands 9q34.1 and 22q11.2 at 550-650 band stage of mitosis. The data indicate that the Ph breakpoints are identical in all the 19 cases of CML.