Comparison of Chromosome Constitution in Chronic Myelocytic Leukemia and Other Myeloproliferative Disorders

Abstract

Abstract The frequency of the Ph1 chromosome in freshly aspirated marrow cells of 14 patients with typical chronic myelocytic leukemia processed by a "direct technic" without resort to culture or colchicine was significantly higher (> 75 per cent) than that observed in the cultured blood cells (< 35 per cent) of the same subjects. The karyotypic abnormally of the abbreviated G-group chromosome would appear not to be related to therapy, since the frequency with which it occurred was not materially affected by treatment (including radiation). The Ph1 chromosome was not observed in any of the metaphases of blood or marrow of 12 subjects who had developed a leukemia-like picture complicating either myelofibrosis, polycythemia vera or myeloid metaplasia. A new chromosome abnormality—a shortened D-group chromosome—was observed with about the same frequency in the blood and marrow metaphases of a female patient with treated chronic myelocytic leukemia. This new karyotypic abnormality was associated with the highest frequency of the Ph1 chromosome in cultured blood cells in the group studied. The Ph1 chromosome was observed in the metaphases of a patient with the blastic phase of chronic myelocytic leukemia. The variations of the morphology of the Ph1 chromosome are discussed and illustrated, especially in relation to the Y-chromosome. In four patients with an atypical picture of CML, the Ph1 chromosome was not observed either in the marrow or cultured blood.