Abstract
The effect of vaccinia virus on MNNG-induced gastric cancer in rats was studied. Subcutaneous inoculation of the highly attenuated vaccinia virus AS strain at intervals of 3 days from the beginning of the experiment showed prominent antitumor activity not only against adenocarcinoma induced by MNNG in the glandular stomach but also against squamous cell carcinoma in the forestomach. Both UV-inactivated vaccinia virus and the DI strain of mammalian pathogenic vaccinia virus, from which the AS strain originated, showed no antitumor effect.