INTERFERON ENHANCEMENT OF TAMOXIFEN EFFICACY IN EHRLICH ASCITES-CARCINOMA - A FOLLOW-UP-STUDY OF TISSUE POLYPEPTIDE ANTIGEN

The aim of the present study was to evaluate the possible synergistic effect between interferon (IFN) and tamoxifen (TAM) in an in vivo expe rimental cancer model, namely Ehrlich ascites carcinoma (EAC). Surviva l time, average life span and body weight were used to evaluate the tu mor growth and therapeutic efficacy of test drugs. The study was also based on the measurement of the tissue polypeptide antigen (TPA) as a tumor marker in serum and ascitic fluid, during the time course of tre atment. EAC cells were injected i.p. in female Swiss albino mice (1x10 (6) cells/mouse). Three days later therapy was started. Recombinant in terferon alpha 2b (rIFN alpha 2b, 0.5x10(5) U/mouse) and/or TAM (0.1 m g/mouse) were given i.p. twice weekly for 4 weeks, either alone or in combination. The animals were observed for a period of 60 days. Result s of this study indicate that rIFN alpha 2b enhances the antitumor eff ect of TAM against EAC in vivo. The combined therapy improved animal s urvival, average life span and tumor burden as compared to either mono therapies alone. Moreover, the study provides evidence for TPA to be a valuable tumor marker in this experimental mammary ascites tumor mode l viz. EAC.