Title : Chemical carcinogens: an overview
A carcinogen in any agent able to cause cancer in humans or animals increases cancer incidence or malignancy or shortens the latency period. A chemical is considered carcinogenic after being intensively studied by researchers and after one or more agencies evaluated the evidence and determined if it is able to cause cancer. According to the International Agency for Research on Cancer (IARC), the chemicals may be categorized in: Group 1 - carcinogenic to humans (the evidence is sufficient); Group 2A - probably carcinogenic to humans (mainly for experimental carcinogens with limited data to humans; Table 2 ); Group 2B - possibly carcinogenic to humans (mainly for experimental carcinogens with less than limited evidence from humans andless than sufficient evidence from animals); and Group 3 - not classifiable as to its carcinogenicity to humans (for agents that do not fall into any other category). Considering the difficulties in testing substances’ carcinogenicity above, most of the substances are classified as probably, possibly carcinogenic, or not classifiable, and approximately 100 chemical compounds are classified as carcinogenic to humans. Environmental pollutants from industries, residences, and vehicles and chemical effluents from industry are among the chemical carcinogens listed by IARC, and the list has been continuously updated. The chemical carcinogens, namely N-methyl-N-nitrosourea, N-butyl-N-(4-hydroxybutyl) nitrosamine, among others, have been used to induce cancer development in animal models of disease, mainly in rodents.
Audience Take Away Notes:
- Present a list of chemical carcinogens.
- Types and mechanisms of action of chemical carcinogens.
- Animals models using chemical carcinogens.