Measurement of the rate of death of canine transmissible venereal tumour cells transplanted into dogs and nude mice.

An intranuclear isotope labelling technique in which the fate of cells labelled with I125-iododeoxyuridine (I125UdR) is monitored, has been adapted for use with dogs. The death rate of injected labelled cells is followed by measuring the appearance of label in the urine. Only a small proportion of injected labelled canine transmissible venereal tumour (TVT) cells survive to contribute to tumour formation when the TVT is transmitted by subcutaneous injection. TVT has also been grown in athymic nude mice and tumour was successfully retransferred to dogs from a nude mouse tumour. Using conventional I125UdR techniques, rapid death of the majority of TVT cells transplanted into nude mice was again encountered. The correlation of dog and nude mouse results emphasises the usefulness of the nude mouse as a model for investigating the kinetics of xenografted tumours.