Inhibition of the R3327MAT-Lu prostatic tumor by diethylstilbestrol and 1,2-bis(3,5-dioxopiperazin-1-yl)propane.

We have previously described the inhibitory effects of diethylstilbestrol on the growth of the androgen-independent, anaplastic Copenhagen rat prostatic tumor, R3327AT, which has a low metastatic potential. We have now selected a variant of the R3327AT tumor that metastasizes exclusively to the lungs, and we have designated it the R3327MAT-Lu. In a dose-response protocol, diethylstilbestrol was inhibitory to the primary R3327MAT-Lu tumor, thereby also inhibiting the formation of lung metastases. Inhibition was also observed in this model tumor by the chemotherapeutic agent 1,2-bis(3,5-dioxopiperazin-1-yl)propane.