ANTITUMOR EFFECT OF AN ORAL-ADMINISTRATION OF CANTHAXANTHIN ON BALB CMICE BEARING THYMOMA CELLS/

The antitumor effect of canthaxanthin in BALB/c mice bearing a transpl antable thymoma was investigated. Male or female mice received two dif ferent doses of canthaxanthin (7 or 14 mu g/g body wt/day) starting 15 days before tumor inoculation (7 x 10(7) cells ip). Canthaxanthin tre atment delayed the appearance of macroscopic ascites and prolonged ani mal survival. This effect was dose dependent and more evident in femal es than in males. It appeared only when the carotenoid was administere d before tumor transplantation. The antitumor efficacy of the caroteno id was related to its tissue incorporation. Canthaxanthin was incorpor ated in a nose-dependent manner in liver and thymoma cells and to a la rger extent in females than in males. Our study shows the antitumor ef ficacy of canthaxanthin in vivo against a transplantable murine thymom a and points out the importance of dose, administration timing, and se x in the antitumor efficacy of this compound.