Difference between revisions of "Carcinogen"
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The [[National Toxicology Program]], part of the [[U.S. Department of Health and Human Services]], classifies carcinogens in two categories: ''Known'', and ''Reasonably anticipated''.<ref name="NTP">National Toxicology Progam: [http://ntp.niehs.nih.gov/index.cfm?objectid=03CA6383-9766-1F64-6637241FE0114FE9 Questions & Answers about the RoC].</ref> Since 1978, it has produced a list of carcinogenic material along with federal regulations limiting exposure.<ref name="NTP"> | The [[National Toxicology Program]], part of the [[U.S. Department of Health and Human Services]], classifies carcinogens in two categories: ''Known'', and ''Reasonably anticipated''.<ref name="NTP">National Toxicology Progam: [http://ntp.niehs.nih.gov/index.cfm?objectid=03CA6383-9766-1F64-6637241FE0114FE9 Questions & Answers about the RoC].</ref> Since 1978, it has produced a list of carcinogenic material along with federal regulations limiting exposure.<ref name="NTP"> | ||
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Revision as of 18:38, April 26, 2007
A carcinogen is any substance capable of causing cancer.[1] Carcinogens do not always cause cancer. Risk factors include the length and intensity of exposure and the genetic makeup of the individual.[2]
Identification
Laboratory studies are the primary source for identifying carcinogens. In these studies, it is assumed that if a large dose (usually higher than common human exposure)of a substance causes cancer in cell cultures or animals it will also cause cancer in humans.[2]
Epidemiologic studies are another importance source of information about carcinogens. These focus on the interactions of human populations with the substances found in their environments. It is difficult to identify carcinogens through these studies because of their uncontrolled nature, but they aid scientists in making educated assessments of the cancer-causing ability of suspected carcinogens.[2]
Classification
There are two main ways in which carcinogens are classified. The main classification is produced by the International Agency for Research on Cancer, the other by the National Toxicology Program.
International Agency for Research on Cancer
The International Agency for Research on Cancer (IARC), which is part if the World Health Organization, produces the most widely used system for classifying carcinogens in its Monographs, published since 1971.[3] Substances are classified by IARC as to their carcinogenic hazard to humans: Established, Probable, Possible, Unclassifiable, and Not probable.[4] The group qualifiers probable and possible have no quantitative significance but are used as descriptors of different levels of evidence of human carcinogenicity.[5]
National Toxicology Program
The National Toxicology Program, part of the U.S. Department of Health and Human Services, classifies carcinogens in two categories: Known, and Reasonably anticipated.[6] Since 1978, it has produced a list of carcinogenic material along with federal regulations limiting exposure.<ref name="NTP">
- ↑ Compact Oxford English Dictionary.
- ↑ 2.0 2.1 2.2 American Cancer Society: Known and Probable Carcinogens
- ↑ http://monographs.iarc.fr/index.php
- ↑ IARC: Classifications
- ↑ Group definitions.
- ↑ National Toxicology Progam: Questions & Answers about the RoC.