Preliminary indirect immunofluorescence studies on the
zinc glycinate marker (ZGM) were compared with
carcinoembryonic antigen (CEA) immunofluorescence, ZGM, detected in 26 of 29 human
colon adenocarcinomas, was associated with the epithelial component of the malignant glands. Fluorescence was generally less strong and more granular for ZGM than for CEA and was found in intraglandular spaces,
luminal border areas, and cytoplasm. ZGM concentration and tissue localization appeared to be related to
tumor differentiation. ZGM was also detected in benign colon mucosae (adjacent to and distant from the
carcinomas) from patients with colon
carcinoma, but differed from CEA in that it was present in the deep crypt portion only. Gastric, pancreatic, esophageal, and anal
adenocarcinomas, as well as benign gastric pyloric and small bowel mucosae had detectable ZGM. CEA, but not ZGM, was observed in 20 nongastrointestinal
carcinomas to date. Studies are under way to determine whether ZGM is a marker associated with colon and gastrointestinal
adenocarcinoma specifically or undifferentiated crypt cells of the colon and digestive tract in general.