The substances, radiations, or radionuclides which are directly involved in the formation of cancer are called carcinogenic substances or carcinogens and this process is called carcinogenicity.
The carcinogenic substances have the ability to damage the genome or disrupt the cells which are involved in the process of metabolism. There are many radioactive substances which are considered to be carcinogenic, but their carcinogenic behaviour is caused by the radiation that they emit. Gamma rays and alpha particles are examples of carcinogenic substances. We also have non-radioactive carcinogens like tobacco smoke, certain dioxins, and inhaled asbestos. Tobacco smoke produces harmful gases like carbon monoxide which are cancer causing substances. Carcinogenic substances are often thought of as synthetic chemicals but in reality, they can be both natural and synthetic. The carcinogenic substances need not be toxic immediately, they are insidious.
Cancer is a group of diseases that cause abnormal cell growth with the potential to spread to other parts of the human body. It is a disease where cells of the body get damaged. Carcinogenic substances generally increase the risk of cancer because they damage the metabolic cells of the body. They also damage the DNA component of the cell which is directly associated with many biological processes in the body. This leads to tumours.
Aflatoxin B1 is produced by a fungus. It grows on the surface of grains, peanut butter, and various nuts and is a naturally occurring microbial carcinogenic substance. The virus hepatitis B and human papilloma can also cause cancer to the person who is infected by them.
Apart from viruses, fungus and radiation there are many other carcinogenic substances. The substances such as benzene and polynuclear hydrocarbons having more than two benzene rings which are fused together also have carcinogenic effects. These polynuclear hydrocarbons are formed when incomplete combustion of organic material such as tobacco, coal, and petroleum takes place. These substances enter the human body and undergo biochemical reactions. This damages the DNA cells and causes cancer further leading to death.
Toxicity is defined as the degree to which a chemical can damage the human cells of a body. We have seen the effect of carcinogenicity and the substances associated with it. These substances are highly toxic in nature and their use should be avoided in order to sustain a healthy body.