Chromosomal aberrations in monitoring exposure to mutagens-carcinogens.

Determination of chromosomal aberration rates in cultured lymphocytes is an established method of monitoring populations occupationally or environmentally exposed to known or suspected mutagenic-carcinogenic agents. Subjects and controls for chromosome studies should be properly selected. Methods of culturing lymphocytes should be standardized, to minimize technical factors which might affect the yield of aberrations. Types of aberrations, their significance, criteria for scoring, reporting and statistical analysis are discussed. From the available experience, the following points must be taken into consideration: Several factors may create confounding, due to nonspecificity of chromosomal aberrations. Persistence of aberrations for years and decades in long-lived lymphocytes makes them an indicator of past damage, but limits the value of the test in monitoring present low-level exposures in subjects with past exposure(s). No clear-cut dose-response relationships have so far been demonstrated, but there is evidence that the method might not be sensitive enough for monitoring very low-level chronic exposures. Results should be evaluated mainly on a group basis. The method is time-consuming, and therefore expensive. Chromosomal damage indicates a biological effect on the genome, the implications of which for carcinogenesis and mutagenesis are still unknown. It is generally believed that increased rates of chromosomal aberration in a population may indicate an increased cancer risk for the group, but not for the single individual presenting excess damage.