Effect of estrogen on tumor-associated immunity in patients with adenocarcinoma of the prostate.

Tumor-associated antigen-induced leukocyte adherence inhibition has been used as an in vitro criterion for evaluating the effect of estrogen on cell-mediated antitumor-associated immunity in patients with adenocarcinoma of the prostate. Significant (p less than 0.05) suppression from the reactivity obtained with untreated patients' leukocytes to allogeneic extracts of malignant prostatic tissue ranging from 19 to 80% was observed in all patients following preincubation of their leukocytes with diethylstilbesterol diphosphate. The observed suppression of tumor-associated immunity in the presence of exogenous estrogen provides further evidence to earlier studies that demonstrated estrogenic suppression of nonspecific cellular responsiveness as evaluated by phytohemagglutinin-induced lymphocytic blastogenesis of normal and prostatic cancer patients' lymphocytes and for the initially suggested concern over the efficacy of estrogenic therapy and its adverse effect on host cell-mediated immunological responsiveness.