Further evaluation of the effect of estrogen on tumor-associated immunity in prostatic cancer.

Reactivity of leukocytes to allogeneic extracts of malignant prostate from patients with prostatic cancer, as evaluated by antigen-induced leukocyte-adherence inhibtion, was significantly suppressed in the presence of diethylstilbestrol diphosphate. The observed suppression of tumor-associated immunity in the presence of exogenous estrogen provides further evidence supporting earlier studies that demonstrated estrogenic suppression of nonspecific cellular responsiveness, as evaluated by phytohemagglutinin-induced lymphocytic blastogenesis, and for the initally suggested concern over the efficacy of estrogenic therapy and its adverse effect on host cell-mediated immunologic responsiveness.