Evaluation of cytochemical methods of studying the localization of alkaline phosphatase in B. subtilis

: The occurrence of a tumour-specific antigen in the intestinal tumours (induced in 51 albino rats by subcutaneous injection of 1,2-dimethylhydrazine), as well as in the blood serum was studied by double immunodiffusion in agar gel. Intestinal tumours proved to contain a water-soluble antigen absent in other tissues, including the colonic mucosa of control animals. This antigen was found in 70 per cent of the tumour-bearing rats. The antigen is perchloric acid-solubilized and is also present in the embryonic tissues in toto on the 7th and the 9th days of rat gestation. The features of this antigen were analogous with those of the carcino-embryonic antigen in human digestive tract tumours.