Chemical carcinogenesis and the pancreas.

Although carcinoma of the pancreas is an increasingly prevalent form of human cancer, there has been relatively little experimental work on the etiology of this tumor until recently, probably because of the lack of adequate experimental models. However, at least two good experimental systems are now available. Several epidemiologic investigations suggest that chemical carcinogens may induce cancer of the pancreas in humans. If this is so, chemicals must reach the pancreas either through the blood supply or by reflux into the pancreatic duct from bile or duodenal contents. The route of exposure may vary according to the chemical and physical characteristics of different chemical carcinogens. Additional work is needed to determine the ability of different classes of chemicals to reach the pancreatic duct by these routes and the presence of enzymes required for activation of carcinogens in the pancreas. Levels of such enzymes as well as the response of cells of the pancreatic duct to carcinogens may be affected by the physiologic state of the pancreas or pathologic conditions within it. Research is needed to investigate these possibilities.