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

The frequency of the Ph¹ chromosome in freshly aspirated marrow cells of14 patients with typical chronic myelocytic leukemia processed by a "directtechnic" 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-groupchromosome would appear not to be related to therapy, since the frequencywith which it occurred was not materially affected by treatment (including radiation). The Ph¹ chromosome was not observed in any of the metaphases ofblood or marrow of 12 subjects who had developed a leukemia-like picturecomplicating either myelofibrosis, polycythemia vera or myeloid metaplasia. Anew chromosome abnormality—a shortened D-group chromosome—was observed with about the same frequency in the blood and marrow metaphases ofa female patient with treated chronic myelocytic leukemia. This new karyotypicabnormality was associated with the highest frequency of the Ph¹ chromosomein 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 arediscussed and illustrated, especially in relation to the Y-chromosome. In fourpatients with an atypical picture of CML, the Ph¹ chromosome was not observed either in the marrow or cultured blood.

Submitted on April 25, 1962 Accepted on June 7, 1962