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Are some progestins genotoxic liver carcinogens?
Giovanni Brambilla1, Antonietta Martelli
1Department of Internal Medicine, Division of Clinical Pharmacology and Toxicology, University of Genoa, Viale Benedetto XV 2, I-16132, Genoa, Italy. farmdimi@unige.it
Mutation Research
|December 5, 2002
Summary
Progestins, including cyproterone acetate, can be possibly carcinogenic. Studies show these drugs form DNA adducts and cause DNA repair, indicating potential genotoxicity, especially in female rats.
Area of Science:
- Toxicology
- Carcinogenesis
- Molecular Biology
Background:
- Progestins are classified as possibly carcinogenic to humans by the International Agency for Research on Cancer (IARC).
- Cyproterone acetate, a synthetic progestin, has demonstrated activation to reactive species in the liver, forming DNA adducts and inducing DNA repair in hepatocytes.
- This genotoxic response is observed in both male and female humans, but is significantly higher in female rats compared to males.
Purpose of the Study:
- To investigate the genotoxic potential of cyproterone acetate and related progestins.
- To explore the mechanisms of DNA damage and repair induced by these compounds.
- To assess the implications of progestin genotoxicity in the context of human cancer risk.
Main Methods:
- Hepatocyte studies in rats and humans to detect DNA adducts and repair mechanisms.
- Analysis of DNA damage markers, including micronuclei formation and mutations, in rat liver cells.
- Comparison of genotoxic effects among different synthetic progestins with similar chemical structures.
Main Results:
- Cyproterone acetate induces DNA adducts and DNA repair in human and rat hepatocytes.
- Female rats exhibit a higher frequency of genotoxic effects, such as mutations and preneoplastic lesions, compared to males.
- Other synthetic progestins (chlormadinone acetate, megestrol acetate) and potassium canrenoate show similar genotoxic potential.
- Standard genotoxicity tests may underestimate progestin risks due to inadequate metabolic activation or target cell selection.
Conclusions:
- Progestins, particularly cyproterone acetate, possess genotoxic properties that warrant further investigation.
- The observed genotoxicity, especially the induction of DNA damage and repair, suggests a potential role in carcinogenesis.
- The classification of estrogen-progestin oral contraceptives as carcinogenic by IARC may be partly attributable to the progestin component.