Chemical Carcinogenesis

Mounika Reddy By Mounika Reddy, 26th Apr 2012 | Follow this author | RSS Feed
Posted in Wikinut>Health>General Health>Diseases & Infections

Here i talk about the steps involved in Chemical Carcinogenesis and types of chemical carcinogens.

Chemical carcinogenesis

First of all, what is a carcinogen: Any substance which can cause cancer.
Now, what is a chemical carcinogen: A chemical agent which can cause cancer.
So, what is chemical carcinogenesis: It is a process by which a chemical agent causes cancer.

In 18th century, Sir Percivall Pott related the increased incidence of scrotal skin cancer in chimney sweeps to chronic exposure to soot. Few public health measures since that time (members should take bath daily) have successfully controlled that cancer. Later, so many chemicals have been shown to be carcinogenic in nature.
Example: Polycyclic aromatic hydrocarbons, products of incomplete combustion, some synthetic products created by the industry.

Steps involved

1) Initiation: When the cells are exposed to a sufficient amount of carcinogen (or initiator), then Initiation starts. This step is rapid and irreversible. In an initiated cell, DNA damages(mutations) occur, making it capable of giving rise to tumor. However, initiation alone is not sufficient for tumor formation.
2) Promotion: By the application of a chemical called promoter, the initiated cells proliferate and expand clonally. This is called as Promotion. Promoters are nontumorigenic by themselves but when they are applied to initiated cells, they can induce tumors. Ex: Phorbol esters, hormones, phenols, certain drugs.

So, first initiation should occur followed by promotion, to induce a tumor.

Types of chemical carcinogens

There are two types.
1) Direct acting compounds: Which do not require chemical transformation for their carcinogenecity. Ex: Dimethyl sulfate, dimethylcarbamyl chloride
2) Indirect acting compounds or procarcinogens: Require metabolic conversion in vivo to produce final carcinogen capable of carcinogenecity. Ex: Polycyclic aromatic hydrocarbons like benzopyrene, microbial products like Aflatoxin and griseofulvin, insecticides, fungicides, nickel, chromium.

Tags

Aflatoxin, Carcinogen, Carcinogenesis, Hormones, Initiation, Polycyclic Aromatic Hydrocarbons, Promotion, Tumor

Meet the author

author avatar Mounika Reddy
I love writing; an efficient way to pen down my thoughts and feelings. I write on biotech, health, personal experiences, recipes etc. Also find my writings at "http://www.expertscolumn.com"

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