INDIVIDUAL EXPRESSION OF CARCINOGEN-METABOLIZING ENZYMES - CYTOCHROMEP4502A

Expression of enzymes metabolizing drugs, carcinogens, and other chemi cals (''xenobiotics'') is regulated by the interplay of genetic, host, and environmental factors, leading in human populations to a marked i nterindividual variability. On this basis it is speculated that indivi dual differences in cancer susceptibility, could be explained to a cer tain extent by interindividual differences in metabolic activation. CY P dependence of carcinogen activation is briefly reviewed; CYP2A6 as a more specific example and some consequences and corollaries are brief ly discussed. At present, no consensus has been reached about the sign ificance of interindividual differences (genetic or nongenetic) in car cinogen metabolism in. cancer etiology. The likely reason is that chem ically induced cancer is still a multifactorial, multistage disease in volving numerous events before a clinically manifested disease develop s. Molecular biological methods such as RFLP and PCR-based techniques as well as molecular dosimetry are making it possible to investigate t he genetic background of individual subjects and environmental influen ces without biases caused by diseases, age, treatment, and other facto rs, which have plagued studies thus far.