Antitumor activity of ascorbic acid in combination with antitumor agents against Lewis lung carcinoma.

Antitumor activity of ascorbic acid in combination with antitumor agents (mitomycin C and 5-fluorouracil) was examined against subcutaneously implanted Lewis lung carcinoma-bearing C57BL/6 mice by feeding them an ascorbic acid-deficient diet. The mice were divided into four groups: group 1 received intraperitoneally mitomycin C (2 mg/kg) and 5-fluorouracil (50 mg/kg) once a week for four weeks beginning from the day after implantation of tumors, as well as ascorbic acid (1000 mg/kg) twice a week for the same four weeks; group 2 received only mitomycin C and 5-fluorouracil; group 3 received only ascorbic acid; group 4 received a vehicle (physiological saline). Tumor growth of group 1 compared with the other three groups, and that of group 2 compared with groups 3 and 4, was significantly inhibited by day 13 post implantation. Histological examinations of tumor tissues at 10 days after implantation of tumors already showed degenerative changes which indicated these antitumor effects.