Chromosomes and causation of human cancer and leukemia. XXV. Significance of the Ph1 (including unusual translocations) in various acute leukemias

The following rare Ph1positive chromosome constitutions, based on the cytogenetic findings in three cases with acute leukemia, are presented. 1) A hypodiploid karyotype, primarily 43,‐X,‐7,‐8,9p+ and a Ph1, in a patient with acute lymphoblastic leukemia (ALL) in relapse, followed by a complete remission and a normal chromosomal picture and then by the appearance of cells with a 46,XX,Ph1 karyotype. The Ph1 was due to a standard translocation between chromosomes #9 and #22. 2) The first demonstration of an unusual Ph1‐translocation between chromosomes #19 and #22 in a condition other than chronic myelocytic leukemia (CML), i.e., acute myeloblastic leukemia (AML). 3) The presence of a Ph1 in acute erythroleukemia (EL) due to a translocation between chromosomes #4 and #22, this apparently being the first description of such a translocation in any disease. The cytogenetic findings, particularly those in the Ph1‐positive case of ALL, were evaluated in relation to the cytologic and immunologic features, clinical courses and implications, and the interrelationship between the three conditions (AML, blastic phase of CML and ALL), which have to be considered in cases of Ph1‐positive acute leukemia.