[Cell cycle and proliferative pool of human tumor strains transplanted into athymic mice]

Autoradiography was used to study the cell cycle periods and proliferative pools of human tumor strains (Ewing's sarcoma, melanoma, Wilms' tumor, renal carcinoma) transplanted in nude mice. The duration of cell cycles was found to be as follows: 22.2 h for Ewing's sarcoma; 16.3 h for melanoma; 22.8 h for Wilms' tumour; 28.2 h for renal carcinoma, with the proliferative pools being equal to 90.1; 89.9; 71.7 and 21%, respectively. The shorter duration of the melanoma strain cycle is primarily accounted for by the reduced S phase.