[Combined laboratory/epidemiological studies on endogenous nitrosation and human cancer]

Endogenous formation of carcinogenic N-nitroso compounds has been suspected of being associated with an increased risk for cancer of the stomach, esophagus and bladder, but no convincing epidemiological evidence has been presented. For these reasons, a new, non-invasive method for quantitative estimation of endogenous nitrosation in humans has been developed on the basis of the findings that certain non-carcinogenic N-nitrosamino acids such as N-nitrosproline are excreted unchanged almost quantitatively in the urine. Some results from the application of this method to clinical and epidemiological studies to evaluate the role of endogenous nitrosation in human cancer are presented.