Cancer Hazard Identification Integrating Human Variability: The Case of Coumarin.

Area of Science:

• Toxicology
• Carcinogenesis
• Metabolism studies

Background:

• Coumarin, a naturally occurring benzopyrone, is widely used as a flavoring and fragrance agent.
• Scientific evidence on coumarin's carcinogenicity requires comprehensive evaluation, integrating diverse data types.

Purpose of the Study:

• To review and assess the scientific evidence regarding coumarin's carcinogenicity.
• To integrate animal carcinogenicity data with mechanistic, toxicogenomic, genotoxicity, metabolism, and human variability studies.

Main Methods:

• Reviewed animal carcinogenicity studies, toxicogenomic, genotoxicity, and metabolism data.
• Analyzed functional pathways affected by coumarin in rat liver and human hepatocytes.
• Investigated the role of CYP2A6 enzyme variability in coumarin metabolism and toxicity.

Main Results:

• Tumor increases observed in multiple rat and mouse studies across various tissues.
• Functional pathway analysis revealed coumarin affects common cancer-related biological processes.
• Compromised coumarin 7-hydroxylation by CYP2A6 shifts metabolism, increasing harmful electrophilic metabolites.

Conclusions:

• Mechanistic data support coumarin's carcinogenicity through electrophilic metabolite formation, genotoxicity, and oxidative stress.
• Metabolism, human variability in CYP2A6, and coumarin-induced hepatotoxicity raise carcinogenicity concerns.
• Integrating human variability data is crucial for accurate cancer hazard identification.