Use of mutagenicity assays in studies of human cancer.

Analysis of human body fluids and excreta for mutagenic activity is used for monitoring occupational exposure to mutagens and carcinogens and for investigating the aetiology of human cancer, especially tumours of the gastro-intestinal tract. The assays most commonly used for these studies employ reverse mutation from amino-acid auxotrophy to prototrophy in bacteria. The critical features of such tests are reviewed, together with the major variables which may confound the interpretation of data collected from such studies. The most important confounding variables are use of tobacco, diet and intake of medicines and drugs. The advantages and disadvantages of body-fluid analysis are summarised and a comprehensive bibliography is provided.