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 mea surement of the cell parameters of leukemia cells in vivo. The range o f S-phase times was measured by using a two color BrdUrd/PI analysis t o determine the range of BrdUrd incorporation into cells which had bee n in S-phase throughout the entire duration of BrdUrd administration. These data were, in turn, used to calculate the range of cell cycle ti mes amongst the leukemia cells present within individual patients. The range of cell cycle times amongst the leukemia cells present within i ndividual patients differs between patients, with some leukemia cell p opulations characterized by narrow and others by broad ranges. In gene ral, the longer the mean cell cycle time (between 27 and 112h) the bro ader the range of cell cycle times. These differences may help to expl ain, in part, the differences in response to therapy among patients wh ose mean leukemia cell kinetic parameters are similar.