[History of tumor markers for cancers of the digestive system]

Tumor markers are gene products which signal the occurrence of tumors in different organs as well as their response to surgery and chemotherapy. The discovery of tumor markers occurred after the demonstration of tumor-specific transplantation antigens in chemically or virally induced tumors in syngenic rodents. The history of currently used tumor markers began in the 1940s, the first discovered being alpha-fetoprotein in 1956, followed by that of carcinoembryonic antigen in 1965. Since then the range of tumor markers has widened continously. Their chemical structure and genetics is now well known. Some may play part in tumor growth and development of metastases. The potential uses of tumor markers are general or high risk population screening, adjunct in diagnosis of cancer, preoperative indicator of tumor burden, indicator of therapeutic success, evidence of postoperative recurrences and use in tumor localization. However, there is no ideal tumor marker fulfilling all the criteria. Isotope-labeled anti-carcinoembryonic antigen antibodies and small molecular E-selectin inhibitors could play a role in the molecular radio- and chemotherapy of colon and pancreatic carcinomas.