Cytogenetic monitoring of human populations at risk in Egypt: role of cytogenetic data in cancer risk assessment.

Somatic mutation plays a critical role in carcinogenesis. Numerous environmental agents can increase the probability that somatic mutation will occur. The use of genotoxicity testing is essential for assessing potential human toxicity so that hazards can be prevented. Cytogenetic monitoring of human populations exposed to chemicals has proved to be a useful tool for detecting the chemical mutagenic effects. Cytogenetic analyses of human chromosomes in peripheral lymphocytes allows direct detection of mutation in somatic cells. Different methods can be used for chromosomal analysis (conventional chromosomal analysis, sister chromatid exchange, micronucleus frequency detection). Micronucleus frequency can be detected either in peripheral blood lymphocytes or in exfoliated cells. Different examples of human population studies are presented. Several problems that are found in biomonitoring studies are discussed. These studies should help us learn about individual exposure assessment and biologically relevant doses, leading to quantitative assessment of human cancer risks.