Validated biomarker responses influence medical surveillance of individuals exposed to genotoxic agents.

There is currently a vast armamentarium of biomarkers for evaluating human exposures to environmental carcinogens, the effects of such exposures and/or susceptibility to disease outcome. Before application, however, these biomarkers require validation in terms of truly reflecting what is claimed. Transitional epidemiological studies bridge the gap between laboratory and field.

HPRT mutations in humans: biomarkers for mechanistic studies.

The X-chromosomal gene for hypoxanthine-guanine phosphoribosyltransferase (HPRT), first recognized through its human germinal mutations, quickly became a useful target for studies of somatic mutations in vitro and in vivo in humans and animals. In this role, HPRT serves as a simple reporter gene. The in vivo mutational studies have concentrated on peripheral blood lymphocytes, for obvious reasons.

Genetic instability in human T-lymphocytes.

Mutations arising in vivo in the hypoxanthine-guanine phosphoribosyltransferase (HPRT) gene of T-lymphocytes provide a measure of mutation induction in human somatic cells. Studies of measured background HPRT mutant frequency (MF) values show wide inter-individual variation. At the extremes are individuals with 'outlier' MF values, i.