Assessment of tumour growth and of response to chemotherapy of human melanomas in athymic, nude mice.

The growth of 6 different human melanomas xenografted into athymic mice was followed by measuring 2 vertical diameters twice weekly. The growth rate of the xenografts was expressed as the tumour doubling time, measured in the volume range 30-60 mm3. None of the xenografts increased their growth rate with increasing number of passages. The tumour lines, which were histologically very similar, showed individual, characteristic growth rates differing by a factor of 3. Evidence was obtained that resistance to cytostatic drugs in the patients is retained in the xenograft. Procedures for evaluating response to chemotherapy are discussed.