The zinc glycinate marker in human colon carcinoma

In an attempt to identify new tumor markers in human colon carcinoma, we produced antisera in rabbits tolerant to normal human tissue antigens and immunized with zinc glycinate-treated extracts of liver metastases from a colon carcinoma. These antisera reacted with carcinoembryonic antigen and with an additional component present in the tumor extracts but not detected in the extracts of normal tissues. The new component, the zinc glycinate marker (ZGM), had an alpha2 mobility on immunoelectrophoresis, was soluble in 1 M perchloric acid, and had a molecular weight of approximately 2X10(6), as indicated by its elution pattern on Sepharose 6-B chromatography. It differed from alpha fetoprotein, nonspecific cross-reacting antigens (NCA, NGP, or CCA III), ferritin-like molecules, and blood group substances A, B, H, Lewis a, and Lewis b. The ZGM was similarly identified in saline or zinc glycinate extracts of 11 of 23 carcinomas of the colon. With routine hematoxylineosin staining, no histologic differences were apparent between tumors bearing the antigen and those without it.