Cell kinetic analysis of a human melanoma in vitro and in vivo-vitro

SUMMARY-The cell kinetic parameters of the same human melanoma maintained in tissue culture and analyzed in vitro and in vivo-vitro were determined. The in vitro data were obtained by the percent labeled mitosis method (aFter a short exposure to tritiated thymidine), by the double-labeling technique, and by the continuous-labeling technique. The in vivo-vitro procedure utilized the double-labeling technique (tritium- and carbon-14-labeled thymidine). The values For cells growing in vitro (with the corresponding in vivo-vitro values given in parentheses) were as Follows: labeling index=0.25 (0.23); DNA synthesis time (Ts) =14.5 hours (15.9); G2+0.7 M=5.3 hours; Gl=16.3 hours; cell-cycle time = 36.1 hours(40); and growth Fraction=0.62 (0.58). Ts was determined in 2 other ways: 1) Cells growing in culture were double-labeled (Ts = 15.6 hours); and 2) cells From a bone marrow aspirate were double-labeled in vitro (Ts = 15.7 hours).-J Nat Cancer Inst 47: 519-526,1971. AGENTS USED to treat cancer, such as chemo