Comparative Analyses of the Timing and Magnitude of Genotoxic and Nongenotoxic Cellular Effects in Urinary Bladder Carcinogenesis

Abstract

Risk assessment is a complex process. It attempts to relate adverse health effects, such as cancer induction, to exposure to potentially toxic agents. The relationship between exposure and tumor incidence is studied experimentally by administering specific exposure regimens to animals followed by lifetime observation to determine tumor incidence. A pivotal issue in risk assessment centers around the estimation of risk at low exposure levels, levels significantly below those typically used in experimental toxicology studies. To quantitatively estimate risk at low exposure levels, mathematical modeling and extrapolation procedures are necessary.