Chromosomes and causation of human cancer and leukemia. XLII. Ph 1-positive ALL: An entity within myeloproliferative disorders?

Abstract

The clinical, survival, and cytogenetic features of 8 cases with Philadelphia chromosome (Ph 1)-positive acute lymphoblastic leukemia (ALL) have been presented. Based on these data, and taken in conjunction with surface marker and enzymic characteristics of the leukemic cells, it is proposed that Ph 1-positive ALL, though sharing many of the clinical and laboratory aspects of Ph 1-negative ALL, is in some cases probably a disease of the pre-B cell type, or its close lymphoid entity, with such cell probably originating from a myeloid precursor. The reversion of Ph 1-positive ALL to chronic myelocytic leukemia (CML) and the many common features it shares with the lymphoid blastic phase (BP) of CML, as well as the rare appearance of acute myeloblastic leukemia (AML) or myeloid features subsequent to complete remission (CR) of Ph 1-positive ALL, when taken together indicate that Ph 1-positive ALL is probably a disease within the myeloproliferative disorders. The cell predominating at any one moment decides the character of the disease, which may vary from ALL to CML to AML and to the BP of CML. The literature on Ph 1-positive ALL is reviewed and tabulated and the various cytogenetic, survival, and clinical features of the disease discussed and delineated. Some of the confusing elements of Ph 1-positive ALL versus the BP of CML are also discussed and the two diseases put in perspective in light of the hypothesis of the pre-B cell (or its close lymphoid entities) origin of some of these leukemias.