Assessment of cytogenetic changes in human populations at risk in Egypt.

Humans are exposed to numerous environmental agents that can increase the probability of mutagenicity and carcinogenicity. Most of environmental exposures involve concurrent or sequential exposure to several agents in air, water, and food. Interactive effects in carcinogenesis have been described for a certain number of combinations of agents. They are described in terms of enhancement or inhibition of carcinogenesis. Risk assessment of exposure to environmental agents can start either from laboratory studies after exposure to different agents or from epidemiological studies in relation to actual exposure. The use of genotoxicity testing is essential for assessment of potential human toxicity so that hazards can be prevented. Cytogenetic monitoring of human populations exposed to environmental agents has proved to be a useful tool for detecting their mutagenic effects. Cytogenetic analysis of human chromosomes in peripheral lymphocytes allows direct detection of mutation in somatic cells. Various 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 in this review. Several problems which are found in biomonitoring studies are discussed.