Cancer is the uncontrolled growth and multiplication of cells, without death. Normally, cells die and get replaced in a programmed, controlled manner, which is called apostasis. But here, cells go out of control in growth. Damage to DNAs, in a special manner can cause cancerous growth of cells.

DNAs are programmed in such a manner that, some genes in it tell when and when not to divide itself. Suicidal genes in DNAs tell the cell when to kill itself. This is the normal procedure where older cells get worn out and gives way to newer ones. When this chain breaks up and DNAs stop functioning properly and stop growing and multiplying, it is called cancer.

Once cancer get kick started in human body, body itself through its own mechanisms cannot defend cancer. It is because, body is made to believe that those cancerous cells are part of body, and it is so itself. Due to this, the uncontrolled growth goes on, without any interruption.  At last, it start blocking essential blood vessels, lymph vessels, airways or so, causing dangerous and fatal situation, which may lead to death itself.

What are carcinogens? In brief, carcinogens are cancer causing substances. What are the common types of carcinogens seen? How it works? Working of carcinogens are almost unknown, still now. It is believed to make mutations or sudden inheritable changes in DNA structure of cells. When it occurs, the pre-programmed cells begin to go out of control in their growth pattern and style. This result in a pathetic situation, which leads to cancer.

How carcinogens work? When our body get exposed to carcinogens, free radicals are formed, which knock out electrons from cells, or even from DNAs. This at times can cause changes in DNA and improper DNA changes may result to cancer.

Carcinogens are to be avoided in a number of ways. You can either avoid situations in which you may come into contact with them. For avoiding vehicle smoke, you can either go by train or so. To avoid smoking, simply quit it.  You can wear  helmets or coats, if you have to travel by sun and you are in a area prone to UV radiations caused by ozone holes. Sun protect creams may also help. Also, follow rules regarding to the  exposures to x-rays and so, if you are prone to get hit by them.

There are thousands of them to name. But most commonly, materials like tobacco, arsenic, asbestos etc, tempt to have more effect on human body to cause cancer. It is said that, a car, in its fully locked condition, may develop carcinogenic substances inside it, from plastics, paints, fuel remnants etc inside it, in a week or so.

Even tea and coffee are also included in known carcinogenic substances. But there is no clear cut definition or description on why things go carcinogenic. Radiations such as gamma rays, X-rays etc, in prolonged exposures, can cause cancer. Even UV rays from sun, where ozone hole has been formed, can cause skin cancer called melanoma. The only way to prevent ourselves from getting affected is by avoiding contact with these substances.

Apart from carcinogens, there are some other causes to cancer. Genetic and hereditary causes are some among them. Genetic pre-disposition inherited from ancestors can cause genes to behave abnormally, which inturn cause cancer. Hereditary cancer can be predicted more easily and can be cured, in almost all initial conditions.  It is the premature finding and diagnosis, which makes the decision on fate of patient, whether to survive or not.