Cell sensitivity to exogenous agents as a basis of tumor therapy

Dose-survival relationship of mammalian cells to exogeous agents, as determined by in vitro and in vivo assays, provides a bases for tumor therapy. The dose-survival response can be altered by several cellular factors: (1) cell cycle dependence of sensitivity, (2) growth phase dependence of sensitivity, (3) repair of sublethal damage, (4) repair of potentially lethal damage, and (5) cell-drug interaction. All of these factors are deeply involved in a therapeutic design for tumors. Repair of potentially lethal damage and cell-drug interaction, and the most recent development in studies of these factors, were mentioned in relation to bleomycin action on mammalian cells. On the basis of these cellular factors the pros and cons of different therapeutic designs for bleomycin were discussed. (auth.)