Oncofetal markers for colon carcinomas are CSAp, a nonsulfated mucin, a second trimester fetal antigen, an altered thymidine kinase, a monosialoganglioside, and glycolipid antigens. For gastric carcinoma, they are basic fetoprotein, a sulfoglycoprotein, and for pancreatic carcinomas--POA, an oncofetal pancreatic antigen, and designated as CAPI, an oncofetal antigen. Tumor-associated markers for colon carcinomas are: UDP-galactosyltransferase and zinc glycinate marker; for gastric carcinomas, sulfated glycoprotein and for pancreatic carcinomas, pancreas carcinoma-associated antigen, a polycytidylic acid-specific ribonuclease, and galactosyltransferase. Suggested as tumor-specific markers for colon carcinomas are an altered mucoprotein, basic antigen, beta 2-microglobulin-associated antigen, and a specific adenosine deaminase; for gastric carcinomas, a specific protein, an antigen with 3-oxyanthranilic acid, and an antigen of unknown origin in gastric secretions; for pancreatic carcinomas, an antigen with molecular weight of 380,000 daltons and an antigen suggested by tumor immunity.