Aberrations of chromosome No. 1 in blastic phase of chronic myeloid leukemia

Aberrations of chromosome No. 1 were detected at the time of blastic crisis in 7 patients with Ph1-positive chronic myeloid leukemia (CML). Two patients had trisomy 1; trisomy for a long arm segment of chromosome No. 1 was present in 2 patients; trisomy for a short arm segment occurred in 2 patients; and one patient had an apparently balanced translocation affecting chromosome No. 1. All patients with extra material of chromosome No. 1 were trisomic for the region 1p22–1pter or 1q21–1qter. A survey of abnormalities of chromosome No. 1 in this series and in other patients with CML previously reported show, in all patients, a relative increase or decrease of genetic material of two specific regions: 1q32–1q42 and 1p36–1pter.