Antitumor activity in a rat mammary adenocarcinoma: the effect of cyclooxygenase inhibitors and immunization against prostaglandin E2.

Female Fischer 344 rats bearing the R3230AC mammary tumor were treated with three different inhibitors of cyclooxygenase--indomethacin, ibuprofen, and flurbiprofen (5 mg/kg body weight). After three weeks, the weight and volume of tumors from treated animals were smaller than those of control rats. Rats bearing the same tumor but immunized against PGE2 conjugated to bovine serum albumin showed similar trends in tumor growth inhibition. Thus we conclude that PGE2 plays an important role in the establishment and growth of the R3230AC mammary tumor.