[Anti-tumour effect of UFT on human renal cell carcinoma heterotransplanted into nude mice]

Abstract

1) Using two histologically different human renal cell carcinomas heterotransplanted into nude mice, the antitumour effect of UFT was investigated, and an attempt was made to analyze the properties of the tumour strains where a drug efficacy was noted. 2) The two strains used were the JRC 1 strain (tumour doubling time of 9.4 days, clear cell type, papillary histologic pattern, grade 3) and the JRC 11 strain (tumour doubling time of 2.72 days, granular cell type, anaplastic histologic pattern, grade 4). 3) Two dose groups were set up, one receiving 10 mg/kg of tegafur (FT) and 22.4 mg/kg of uracil and the other receiving 20 mg/kg of FT and 44.8 mg/kg of uracil. Each group was further divided into an early administration group (start of administration 3 days after the tumour transplantation) and a late administration group (start of administration at a time when the transplanted tumour proliferated to weight of 100 to 300 mg). 4) Effect as noted in the tumour proliferation inhibition rate was seen only in the group receiving 20 mg/kg of FT and 44.8 mg/kg of uracil in both early and late administration groups of the JRC 1 strain. Among these groups only the early administration groups showed a histological positive effect. 5) The fact that the measured 5-FU intra-tumour concentration in the JRC 1 strain was only 1/4 that of the JRC 11 strain demonstrates more susceptibility of JRC 1 strain to UFT. Moreover, intratumoral concentration of 5-FU differed markedly even with the same administration method and dosage level. This result indicates that intra-tumour concentration will be different if the histological pattern differs.