Ph1-negative chronic granulocytic leukemia: a nonentity.

Clinical, hematologic, and prognostic differences between Philadelphia chromosome (Ph1)-positive and Ph1-negative chronic granulocytic leukemia (CGL) have been described. However, Ph1-negative disease may be a mixture of other entities. The authors identified 24 patients given the diagnosis of Ph1-negative CGL after evaluation by the Hematology Department of the Mayo Clinic between January 1976 and August 1984. Each patient was Ph1-negative, and a bone marrow examination was interpreted as CGL. Initial peripheral blood and bone marrow samples were available for review in 22 patients. Their disorders were reclassified as chronic myelomonocytic leukemia (13 patients), chronic myelomonocytic leukemia in transformation (1 patient), preleukemic syndrome (3 patients), and undifferentiated chronic myeloproliferative disease (5 patients). Median survival for the 22 patients was 17 months.