Carcinostatic Effect of Extracts from Human Gastric Cancer

Saline extracts from human gastric cancer divided into two parts, one of which was irradiated by X-ray of 2000 r, before homogenization, were fractionated with EtOH, in which S1 was 30% vol. ppt. , S2 was 30-70% vol. ppt. , and S3 was supernatant. Further, S1 and S2 were fractionated with (NH4)2SO4 into P1 (30% sat. ppt. ), P2 (30-50% sat. ppt. ), P3 (50-7O% sat. ppt. ), and P4 (supernatant). The S2P1 and S2P2 fractions non-irradiated inhibited the growth of subcutaneous solid Ehrlich ascites tumor in mice, which were respectively significant at the level of 10% and 5%, but the same fractions irradiated lost the growth inhibitory activity. The S2P3 fraction irradiated inhibited the growth of solid tumor at the level of 20%, and was different from the equivalent non-irradiated fraction having mitosis promoting activity at the significance of 0. 5% level. These data may show that malignant tumor contains the growth inhibiting substance which is not species specific, and the carcinostatic effect of X-ray irradiation is due to the destruction of balance between growth promoting and inhibiting substances inside of the tumor tissue.