On the basis of a bromodeoxyuridine chromosome-labeling method, we have studied the sister chromatid exchange (SCE) incidence and growth pattern in cultured leukemic marrow cells from 12 acute nonlymphocytic leukemia patients, 10 with acute myeloblastic leukemia, 1 with acute erythroleukemia, and 1 with acute promyelocytic leukemia with various karyotypic abnormalities. The leukemia cells in these patients were readily identified on the basis of the chromosome anomalies. There was no clear karyotypic relevance to the SCE incidence and growth pattern among the aneuploid leukemic cells. In most of the cases examined, however, the aneuploid leukemic cells were characterized by a low SCE incidence and considerably prolonged cell cycle time, as compared with those in the normal diploid cells which appeared during remission or coexisted with the leukemic cells at the early stages or during relapse of the disease. In most cases, this situation did not change in the aneuploid leukemic cells even after chemotherapeutic treatment, while the normal diploid cells exhibited an increased SCE frequency and, in some cases, alteration of growth pattern after chemotherapy. Possible differences in the susceptibility to the chemotherapy of the leukemic and normal cells in relation to the different growth capacity of these cells are discussed.
This study was supported in part by Grant CA-14555 from the National Cancer Institute.