Animal studies guide the development of new pharmaceuticals by testing for effectiveness and safety before the drugs are tested in humans. For commercial chemicals and pollutants, animal studies are currently the primary means of identifying carcinogens and guiding exposure reduction to prevent environmental cancers.
The Science Review database includes information on 216 chemicals that increased mammary gland tumors in animal studies conducted by the US National Toxicology Program (NTP) or included in the International Agency for Research on Cancer (IARC) Monographs, 11th Report on Carcinogens (11th ROC), Carcinogenic Potency Database (CPDB), or Chemical Carcinogenesis Research Information System (CCRIS) database. For each chemical, the database includes:
This information is crucial for regulators to consider in decisions about limiting human exposure and for manufacturers to evaluate in reformulating products and re-engineering processes to avoid suspect chemicals. It is also valuable for epidemiologists to identify new chemicals, exposure scenarios, and exposed populations for breast cancer studies.
Please refer to the review and commentary publications for a description of methods, conclusions, and recommendations.
- CPDB: We selected all chemicals with at least one study that reported an increase in mammary gland tumors.
- IARC Monograph summaries: We searched for "mammary" and included those chemicals that increased mammary gland tumors.
- NTP Technical Reports: We included all the chemicals from the NTP website, "Chemicals associated with site-specific tumor induction in mammary gland," which draws from the collection of Technical Reports. We also used the search term "mammary" to select chemicals that increased mammary tumors in the NTP Study Reports Collection: Abstracts and Target sites in 2 year studies.
- NTP 11th Report on Carcinogens: We included those chemicals that were returned after a search for "mammary" and were associated with increased mammary tumors.
- CCRIS: We selected by the search term "mammary" and those that had positive results in the "Carcinogenicity Studies" section.
This list may be incomplete because most chemicals, including most in common use, have never been tested for their carcinogenicity in animals; and so it is not known whether they might cause mammary gland (or other) tumors. The chemicals listed here vary in the strength of the evidence that they are human carcinogens. In order to aid the user in evaluating the strength of evidence, we have compiled references and links to the sources that identified each chemical as a mammary gland carcinogen.
Database development is ongoing and information for some chemicals is currently more complete than for others. For 45 priority chemicals with current or past widespread exposure, we have assembled complete citations for studies reporting mammary gland tumors and for most of those studies that did not report mammary gland tumors. For a smaller subset of chemicals, we have extracted experimental details from the original studies to examine the strength of the evidence more fully. For 11 chemicals that have been the subject of recent risk assessments (ethylene oxide, methylene chloride, vinylidene chloride, MX (3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone), and several PAHs and nitro-PAHs), we also reviewed governmental and non-governmental risk assessments from a wide range of agencies and groups. For a detailed description of methods, please consult the accompanying article.
About