Chemical Carcinogenesis

1.Any discrete chemical compound which has been shown to cause cancer in human or animal studies.
2. Hundreds of individual compounds have been shown to induce cancers. Many thousands of additional compounds are ''suspect'' carcinogens.
3. Many are commonly used in laboratory operations, shops and art studios.

Which classes of chemicals tend to be Chemical Carcinogenesis ?

1. Epoxides: Ethylene oxide ,Propylene oxide
2. Organohalogen comp.:Vinyl chloride Carbon tetrachloride Chloroform Hexachlorobenzene Trichloroethylene
3. Hydrazines: Hydrazine (and salts) 1,2-Dimethylhydrazine
4. N-Nitroso compounds:N-Nitrosodimethylamine
5. Aromatic Amines:Benzidine Aniline o-Anisidine o-Toluidine
6. Aromatic hydrocarbons:Benzene Benz[a]anthracene Benzo[a]pyrene

Classes of Chemical Carcinogenesis (cont.)

1. Misc. organic compounds:Formaldehyde Acetaldehyde 1,4-Dioxane Ethyl carbamate 2-Nitropropane Styrene Thiourea Thioacetamide
2. Misc. inorganic comp.Arsenic and compounds Chromium and comp. Thorium dioxide Beryllium and compounds Cadmium and compounds Lead and compounds Nickel and compounds Selenium sulfide

How do Chemical Carcinogenesis enter the body ?

1. Skin absorption. Many solvents and other chemicals go directly through the skin.
2. Ingestion. Swallowing of a carcinogen.
3. Inhalation. Breathing gases, fumes and vapors is the most common form of exposure.

Mechanism

1. Chemical carcinogens undergo metabolic activation by cytochrome P450 or other metabolic pathway and react with DNA or alter epigenetic mechanism .
2.DNA is considered the ultimate target for most carcinogens to cause mutations or gross chromosomal changes.
3.Formation of DNA Adducts occurs by binding of chemicals to DNA
4. Carcinogen -DNA Adducts leads to base mutation or gross chromosomal changes ,so that it can cause base substitution ,deletion ,insertion duroing DNA replication .

Carcinogenic Chemicals in our daily life.

1.Charred Foods