Radiation and heat sensitivity of cells from human melanoma xenografts. Lack of correlations with tumour growth parameters.
Five human malignant melanomas grown in athymic nude mice were studied. Tumour volume-doubling times were determined from Gompertzian growth curves, vascular volumes from stereological analysis of 2-microns thick tumour sections and DNA histograms by flow cytometric analysis. Single-cell suspensions prepared from the tumours were exposed to radiation or heat (42.5 degrees C; pH 7.4) under aerobic conditions in vitro and the colony-forming ability of the cells was assayed in soft agar. Tumours with short volume-doubling times tended to show higher fractions of cells in S-phase and higher vascular volumes than those with long volume-doubling times. The radiation and the heat sensitivity of the melanoma cells, i.e. the D0-values, were probably not positively correlated with the tumour volume-doubling time, the fraction of cells in S-phase or the vascular volume, or with each other either. The variation in radiation and heat sensitivity among cells from the different melanomas appears not to be due to external factors, but reflects, rather, intrinsic cellular differences.
D000818:Animals; D002470:Cell Survival / Q000528:radiation effects; D002478:Cells, Cultured; D006358:Hot Temperature; D006801:Humans; D008545:Melanoma / Q000098:blood supply / Q000473:pathology*; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D014183:Transplantation, Heterologous