The modification of cancer risk by chemicals

Area of Science:

• Toxicology
• Carcinogenesis Research
• Risk Assessment

Background:

• The binary classification of chemicals as carcinogens or non-carcinogens is challenged by new insights into carcinogenesis.
• Cancer development involves continuous processes, with some cancers attributed to 'bad luck' (unpreventable factors).
• Cancer risk factors are categorized into unmodifiable intrinsic factors and modifiable endogenous and exogenous factors, including chemicals.

Purpose of the Study:

• To propose a dynamic cancer risk model for evaluating chemicals based on their ability to modify cancer risk.
• To shift focus from classifying chemicals to understanding their impact on carcinogenesis pathways.
• To develop improved strategies for cancer risk assessment using diverse data sources.

Main Methods:

• Conceptualizing a dynamic cancer risk model based on an adverse outcome pathway for carcinogenesis.
• Identifying key cellular rates influenced by chemical exposures: cell division, mutation rate, and transformation rate.
• Integrating various data sources for risk assessment, moving beyond traditional long-term bioassays and epidemiology.

Main Results:

• Chemicals can be assessed by their capacity to alter critical rates in the carcinogenesis process.
• The proposed model allows for a more nuanced understanding of chemical impact on cancer risk.
• This framework facilitates addressing complex exposure scenarios, such as partial lifetime exposures and mixtures.

Conclusions:

• A dynamic cancer risk model offers a more effective approach to chemical risk assessment than traditional classification.
• This paradigm shift enables the development of targeted risk management measures for exogenous chemical factors.
• The model supports a broader range of data sources and addresses complex exposure scenarios in cancer risk evaluation.