Carcinogens are agents that can cause cancer. In industry, there are many potential exposures to carcinogens. Generally, workplace exposures are considered to be at higher levels than for public exposures. Safety data sheets (SDSs) should always contain an indication of carcinogenic potential.
A carcinogen is any agent that directly increases the incidence of cancer. Most, but not all carcinogens are mutagens. Carcinogens that do not directly damage DNA include substances that accelerate cell division, thereby leaving less opportunity for cell to repair induced mutations, or errors in replication. Carcinogens that act as mutagens may be biological, physical, or chemical in nature, although the term is most often used in relation to chemical substances.
Examples Of Carcinogens Include
- The International Agency for Research on Cancer (IARC or CIRC in French) distinguishes four main groups or physical factors on the basis of existing scientific data to assess their carcinogenic potential. GROUP 1: the agent may be a carcinogenic mixture for humans (proven carcinogen or certainly carcinogenic). The exposure circumstance entails.
- Carcinogen meaning: 1. A substance that causes cancer: 2. A substance that causes cancer: 3. A substance that can.
- Carcinogens Henk A Tennekes. Experimental Toxicology Services (ETS) Nederland BV, Frankensteeg 4, 7201KN Zutphen, The Netherlands Abstract Most regulatory agencies assume that there is no safe level of exposure to carcinogens but that a threshold, or 'safe' exposure level exists for non-carcinogens.
Human Papilloma Virus (HPV, Figure (PageIndex{4})) is an example of a biological carcinogen. Almost all cervical cancers begin with infection by HPV, which contains genes that disrupt the normal pattern of cell division within the host cell. Any gene that leads to an uncontrolled increase in cell division is called an oncogene. The HPV E6 and E7 genes are considered oncogenes because they inhibit the host cell's natural tumor suppressing proteins (include p53, described below). The product of the E5 gene mimics the host's own signals for cell division, and these and other viral gene products may contribute to dysplasia, which is detected during a Pap smear (Figure (PageIndex{5})). Detection of abnormal cell morphology in a Pap smear is not necessarily evidence of cancer. It must be emphasized again that cells have many regulatory mechanisms to limit division and growth, and for cancer to occur, each of these mechanisms must be disrupted. This is one reason why only a minority of individuals with HPV infections ultimately develop cancer. Although most HPV-related cancers are cervical, HPV infection can also lead to cancer in other tissues, in both women and men.
Figure (PageIndex{4}): Electron micrograph of HPV.(Wikipedia-Unknown-PD)
Figure (PageIndex{5}): Dysplastic (left) and normal (right) cells from a Pap smear.(Flickr-Ed Uthman-CC:AS)
Radiation is a well-known physical carcinogen, because of its potential to induce DNA damage within the body. The most damaging type of radiation is ionizing, meaning waves or particles with sufficient energy to strip electrons from the molecules they encounter, including DNA or molecules that can subsequently react with DNA. Ionizing radiation, which includes x-rays, gamma rays, and some wavelengths of ultraviolet rays, is distinct from the non-ionizing radiation of microwave ovens, cell phones, and radios. As with other carcinogens, mutation of multiple, independent genes that normally regulate cell division is required before cancer develops.
Chemical carcinogens (Table (PageIndex{2})) can be either natural or synthetic compounds that, based on animal feeding trials or epidemiological (i.e. human population) studies, increase the incidence of cancer. The definition of a chemical as a carcinogen is problematic for several reasons. Some chemicals become carcinogenic only after they are metabolized into another compound in the body; not all species or individuals may metabolize chemicals in the same way. Also, the carcinogenic properties of a compound are usually dependent on its dose. It can be difficult to define a relevant dose for both lab animals and humans. Nevertheless, when a correlation between cancer incidence and chemical exposure is observed, it is usually possible to find ways to reduce exposure to that chemical.
Table (PageIndex{2}): Some classes of chemical carcinogens (Pecorino 2008) |
1. PAHs (polycyclic aromatic hydrocarbons) e.g. benzo[a]pyrene and several other components of the smoke of cigarettes, wood, and fossil fuels 2. Aromatic amines e.g. formed in food when meat (including fish, poultry) are cooked at high temperature 3. Nitrosamines and nitrosamides e.g. found in tobacco and in some smoked meat and fish 4. Azo dyes e.g. various dyes and pigments used in textiles, leather, paints. 5. Carbamates e.g. ethyl carbamate (urethane) found in some distilled beverages and fermented foods 6. Halogenated compounds e.g. pentachlorophenol used in some wood preservatives and pesticides. 7. Inorganic compounds e.g. asbestos; may induce chronic inflammation and reactive oxygen species 8. Miscellaneous compounds e.g. alkylating agents, phenolics |
Contributors and Attributions
Dr. Todd Nickle and Isabelle Barrette-Ng (Mount Royal University) The content on this page is licensed under CC SA 3.0 licensing guidelines.
Mention any two group of carcinogens with an example for each!?
1 Answer
A carcinogen is any substance, radionuclide or radiation that promotes carcinogenesis or the formation of cancer.
Explanation:
The International agency for Research on Cancer (IARC) has published a series of Monograms that have been highly influencial in the classification of possible carcinogens.
GROUP 1
The agent is definitely carcinogenic to humans. E.g. 2 naphthylamine, Acetaldehyde.
GROUP 2A
The agent is probably carcinogenic to humans. E.g. Acrylamide, Adriamycin.
GROUP 2B
The agent is possibly carcinogenic to humans. E.g. Aflatoxin, Acetamide.
Chemical carcinogens (Table (PageIndex{2})) can be either natural or synthetic compounds that, based on animal feeding trials or epidemiological (i.e. human population) studies, increase the incidence of cancer. The definition of a chemical as a carcinogen is problematic for several reasons. Some chemicals become carcinogenic only after they are metabolized into another compound in the body; not all species or individuals may metabolize chemicals in the same way. Also, the carcinogenic properties of a compound are usually dependent on its dose. It can be difficult to define a relevant dose for both lab animals and humans. Nevertheless, when a correlation between cancer incidence and chemical exposure is observed, it is usually possible to find ways to reduce exposure to that chemical.
Table (PageIndex{2}): Some classes of chemical carcinogens (Pecorino 2008) |
1. PAHs (polycyclic aromatic hydrocarbons) e.g. benzo[a]pyrene and several other components of the smoke of cigarettes, wood, and fossil fuels 2. Aromatic amines e.g. formed in food when meat (including fish, poultry) are cooked at high temperature 3. Nitrosamines and nitrosamides e.g. found in tobacco and in some smoked meat and fish 4. Azo dyes e.g. various dyes and pigments used in textiles, leather, paints. 5. Carbamates e.g. ethyl carbamate (urethane) found in some distilled beverages and fermented foods 6. Halogenated compounds e.g. pentachlorophenol used in some wood preservatives and pesticides. 7. Inorganic compounds e.g. asbestos; may induce chronic inflammation and reactive oxygen species 8. Miscellaneous compounds e.g. alkylating agents, phenolics |
Contributors and Attributions
Dr. Todd Nickle and Isabelle Barrette-Ng (Mount Royal University) The content on this page is licensed under CC SA 3.0 licensing guidelines.
Mention any two group of carcinogens with an example for each!?
1 Answer
A carcinogen is any substance, radionuclide or radiation that promotes carcinogenesis or the formation of cancer.
Explanation:
The International agency for Research on Cancer (IARC) has published a series of Monograms that have been highly influencial in the classification of possible carcinogens.
GROUP 1
The agent is definitely carcinogenic to humans. E.g. 2 naphthylamine, Acetaldehyde.
GROUP 2A
The agent is probably carcinogenic to humans. E.g. Acrylamide, Adriamycin.
GROUP 2B
The agent is possibly carcinogenic to humans. E.g. Aflatoxin, Acetamide.
Carcinogens Examples Biology
GROUP 3
The agent is not classifiable as to its carcinogenicity to humans. E.g. Aciclovir, Acrolein.
GROUP 4
The agent is probably not carcinogenic to humans. E.g. Azacitidine, Androgenic steroids.
Group 4 Carcinogen
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