Related Experiment Videos
Liver tumors in rodents: extrapolation to man
Advances in Veterinary Science and Comparative Medicine
|January 1, 1987
Summary
Human models poorly predict rodent carcinogens. While many chemicals cause liver cancer in rodents, human exposure levels are typically low, suggesting minimal risk for primary liver cancer.
Area of Science:
- Toxicology
- Hepatocarcinogenesis
- Epidemiology
Background:
- Human models are inadequate for predicting rodent hepatocarcinogens.
- Few agents cause primary liver cancer in humans, including hepatitis B virus, certain steroid hormones, vinyl chloride, and thorium dioxide.
- Aflatoxin is a suspected human hepatocarcinogen, but evidence is circumstantial.
Purpose of the Study:
- To evaluate the risk of primary liver cancer in humans from low-level exposure to rodent hepatocarcinogens.
- To assess the discrepancy between rodent and human responses to hepatocarcinogenic agents.
Main Methods:
- Review of known human hepatocarcinogens and their animal models.
- Analysis of mortality and incidence data for primary liver cancer in England and Wales.
- Comparison of human exposure levels to rodent-effective doses for various chemicals.
Main Results:
- Most chemicals causing liver tumors in rodents do so at doses far exceeding typical human exposure.
- Primary liver cancer mortality is low in areas with widespread low-dose exposure to rodent hepatocarcinogens.
- Observed increases in liver cancer incidence in England and Wales may be due to classification changes, not a true rise.
Conclusions:
- Low-level exposure to rodent hepatocarcinogens likely poses a very small risk of primary liver cancer in humans.
- Human susceptibility to hepatocarcinogens differs significantly from that of laboratory rodents.
- Further research is needed to clarify the human health implications of environmental exposures to potential hepatocarcinogens.