We examined the possibility that the
anti-estrogens, tamoxifen (TX) and toremifen (TO) interacted？with the immune system.
Indeed, both TX and TO stimulated cells mediated cytotoxicity reactions by
various killer cells: killer T (TK), natural killer (NK), lymphokine activated
killer (LAK) cells. Both TX and TO inhibited the growth of tumors that express
estrogen receptors. Thus these antiestrogens inhibited tumor growth and
stimulated killer cells for cytotoxicty on such tumors. Therefore these agents
were presumed to stimulate tumor immunity. We tested the P815 mouse mastcytoma
with TK, LK, and TX or TO. A therapeutic effect was observed in both
experiments. The SL2-5 murine lymphoma was tested with NK and TX cells or TO
cells and successful immunotherapy was observed.？We digested human breast carcinomas and lung tumors with
collagenase. The killer cells were separated from tumor cells on Ficoll
gradients. TX and TO enhanced the cytotoxic effect of autologous killer cells
on the corresponding tumor cells. This experiment indicates that the results
obtained in animals are also valid for human malignant disease.