Cell kinetics were studied in human
leukemia (acute
leukemia, chronic myelocytic leukemia and other myelocytic
malignancies) and in mouse
leukemia (L 1210 cells). Flow cytometry method was employed for the analysis of
DNA distribution of cells stained with
propidium iodide, using a cytofluorograf (System 50, Ortho Instruments). The
DNA per cell frequency distribution histograms (
DNA histogram) in normal human lymphocytes from peripheral blood showed one main peak of diploid, which corresponded to the
DNA from cells in G1 phase of the cell cycle, and other small portions, which corresponded to the
DNA from cells in S, G2 and M compartments (S + G2 + M). The percentage of the number of cells in the S + G2 + M phase to the total cells from normal controls was 2.1%. In the case of untreated
acute myelocytic leukemia (AML), the percentages of cells in the S + G2 + M phase from peripheral blood and bone marrow were 2.4% and 7.1%, respectively. In bone marrow from treated AML, the percentage of cells in the S + G2 + M phase increased to 14.8%. In the case of untreated
acute lymphocytic leukemia, the percentages of the S + G2 + M phase from peripheral blood and bone marrow were 1.9% and 7.1%, respectively. After the treatment of
chronic myelocytic leukemia, the percentages of the S + G2 + M phase in peripheral blood and bone marrow were 5.8% and 12.2%, respectively. The
DNA histogram in untreated L 1210 cells showed two peaks. One of the peak was consisted of the
DNA from cells in G1 phase and another was from cells in the S + G2 + M phase. The proportion of the S + G2 + M phase in the L 1210 cells treated with
antitumor drugs significantly increased compared to the untreated cells. The findings indicate that the increase in the proportion of the S + G2 + M phase in the cells from treated human
leukemia was a result of the
therapeutic effects of
antitumor drugs. The study of cell kinetics may provide benefits to know the effect of
antitumor drugs during the treatment of human
leukemia.