All of us here have a  potential in getting cancer.. just beware guys..

Source : http://www.cancer.org/docroot/CRI/content/CRI_2_2_2X_What_causes_lung_cancer_26.asp?

A risk factor is anything that increases a person's chance of getting a disease such as cancer. Different cancers have different risk factors. Some risk factors, such as smoking, can be controlled. Others, like a person's age or family history, can't be changed. But having a risk factor, or even several, doesn’t mean that a person will get the disease.

Smoking is by far the leading risk factor for lung cancer. Tobacco smoke causes more than 8 out of 10 cases of lung cancer. The longer a person has been smoking and the more packs per day smoked, the greater the risk. If a person stops smoking before lung cancer develops, the lung tissue slowly returns to normal. Stopping smoking at any age lowers the risk of lung cancer. Cigar and pipe smoking are almost as likely to cause lung cancer as is cigarette smoking. There is no evidence that smoking low tar cigarettes reduces the risk of lung cancer.

People who don’t smoke but who breathe the smoke of others also have a higher risk of lung cancer. Non-smoking spouses of smokers, for example, have a 30% greater risk of developing lung cancer than do spouses of nonsmokers. Workers exposed to tobacco smoke in the workplace are also more likely to get lung cancer.

Asbestos is another risk factor for lung cancer. People who work with asbestos have a higher risk of getting lung cancer. If they smoke as well, the risk is greatly increased. Although asbestos was used for many years, the government has now nearly stopped its use in the workplace and in home products. While it is still present in many buildings, it is not thought to be harmful as long as it is not released into the air.

A type of cancer linked to asbestos (mesothelioma) can start in the pleura. The American Cancer Society has information about mesothelioma available through our toll-free number or on our Web site.

Radon is a radioactive gas made by the natural breakdown of uranium. Radon can’t be seen, tasted, or smelled. Radon can become concentrated indoors and create a possible risk for cancer. Smokers are especially sensitive to the effects of radon. State and local offices of the EPA (Environmental Protection Agency) can provide information about how to test for radon in the home.

High radon levels in some mines can increase the lung cancer risk for miners.

Cancer-causing agents in the workplace include uranium, arsenic, vinyl chloride, nickel chromates, coal products, mustard gas, chloromethyl ethers, gasoline, and diesel exhaust. People who work with these substances should be very careful to avoid exposure as much as possible.

Marijuana cigarettes have more tar than regular cigarettes. Many of the cancer-causing substances in tobacco are also found in marijuana. Some medical reports suggest that marijuana could cause cancers of the mouth and throat. But because marijuana is an illegal substance it is not easy to gather information about its effects on the body.

Other diseases such as tuberculosis (TB) and some types of pneumonia often leave scars on the lung. This scarring can increase the risk of developing lung cancer.

Personal and family history: If you have had lung cancer, you have a higher risk of getting another lung cancer. Brothers, sisters, and children of people who have had lung cancer may have a slightly higher risk themselves.

Diet: Some reports suggest that a diet low in fruits and vegetables might increase the risk of lung cancer in people who are exposed to tobacco smoke. Evidence suggests that fruits and vegetables may offer protection against lung cancer.

Gender: Several studies have shown that the lung cells of women are more likely to develop cancer when exposed to tobacco smoke.

Air pollution: In some cities, air pollution may slightly increase the risk of lung cancer. But the risk is still far less than that caused by smoking.

During the past few years, scientists have made great progress in understanding how risk factors produce certain changes in the DNA of lung cells, causing the cells to become cancerous. DNA is the genetic material that carries the instructions for nearly everything our cells do.

Current research in this field is aimed at developing tests that can find lung cancers at an early stage by spotting DNA changes. Other researchers are working on ways to repair or replace these faulty genes in order to stop the growth and spread of cancer cells.