New types of unusual and complex Philadelphia chromosome (Ph1) translocations in chronic myeloid leukemia.

Nine cases of Philadelphia chromosome-positive chronic myeloid leukemia with an aberrant translocation are reported. In three cases an unusual translocation was found, the recipient chromosome being Nos. 14, 17, and 18, respectively. In six cases the translocation involved a third chromosome in addition to Nos. 9 and 22: there were two cases involving chromosome No. 1, two involving chromosome No. 14, one involving chromosome No. 3, and one involving chromosome No. 12. The clinical significance of the aberrant translocations and the translocation mechanism is discussed.