Autoradiographic investigations about the proliferation rate in different areas of human head and neck carcinomas.

Up to five biopsies from the margin of the cancerous area of 10 human laryngeal and pharyngeal carcinomas have been labeled in vitro and partly in vivo after xenotransplantation on thymus-aplastic nude mice. The question should be answered whether or not one single biopsys will represent the proliferation rate of the complete tumor. The results demonstrate that under consideration of the methodical source of error the DNA-synthesizing cells are distributed regularly in the periphery of the carcinomas. One biopsy, therefore, represents the proliferation rate of the whole tumor. This result is only valid for examining the labeling index but not, as discussed, for calculating, e.g., the length of single cell cycle phases. For this purpose, laboratory animals are necessary. The most suitable animals seem to be thymus-aplastic nude mice.