Composition of leukemic cell populations in AKR leukemia and effects of chemotherapy.

With the use of a cell sedimentation technique at 1g, the cytokinetic behavior of leukemic cells from the thymuses of mice with spontaneous AKR leukemia was determined. It was demonstrated that small sized cells were derived from the rapidly-proliferating larger sized cells and appeared to be in a prolonged G1 or resting phase. However, from serial observations of 3H-TdR specific activities and radioautography, these small cells appeared to be constantly renewed, and a significant fraction of these cells were subsequently observed as labeled non-viable cells. This continual transition of cells between compartments may represent one of the major modes of cell death, i.e. age related within the tumor cell population. The relatively high resistance of small cells to various cytotoxic agents was demonstrated.