DISTRIBUTION OF CELL-CYCLE TIMES AMONGST THE LEUKEMIA-CELLS WITHIN INDIVIDUAL PATIENTS WITH ACUTE MYELOGENOUS LEUKEMIA

Seventeen patients with AML received infusions of BrdUrd to permit measurement of the cell parameters of leukemia cells in vivo. The range of S-phase times was measured by using a two color BrdUrd/PI analysis to determine the range of BrdUrd incorporation into cells which had been in S-phase throughout the entire duration of BrdUrd administration. These data were, in turn, used to calculate the range of cell cycle times amongst the leukemia cells present within individual patients. The range of cell cycle times amongst the leukemia cells present within individual patients differs between patients, with some leukemia cell populations characterized by narrow and others by broad ranges. In general, the longer the mean cell cycle time (between 27 and 112h) the broader the range of cell cycle times. These differences may help to explain, in part, the differences in response to therapy among patients whose mean leukemia cell kinetic parameters are similar.