A quantitative comparison of cytogenetic effects of anti-tumor agents.

The relative potency of different anti-tumor agents in inducing structural and numerical chromosome abnormalities and SCEs was assessed by making comparisons at equitoxic doses, measured in terms of colony forming ability, in cultured diploid human fibroblasts. At approximately 20% survival the relative potency of X-rays, daunorubicin, nitrogen mustard, adriamycin, and actinomycin D in inducing structural aberrations was 1.0, 0.85, 0.26, 0.22, and zero, respectively. SCE induction was quantitatively unrelated to the induction of chromosome aberrations. No numerical changes were observed. Accurate assessment of the yields of chromosome aberrations requires the use of multiple sampling times in asynchronous populations.