Even today, most doctors find it difficult to tell the exact cause of why one person gets cancer and another does not. However, some doctors believe that cancer develops over time when certain normal genes start mutating. Such cells, when multiplied rapidly and  malignant, give rise to this deadly disease. These gene mutations are believed to occur due to a complex mix of factors related to lifestyle, heredity and environment.

However it is just a risk factor that increases your chance of developing cancer. Generally, different cancers have different risk factors. Use of tobacco, certain dietary habits, alcohol consumption, exposure to ultraviolet (UV) radiation, and to a lesser extent, exposure to cancer causing agents (carcinogens) in the environment and the workplace are some of the potential catalysts of cancer.

Here are some of the factors which can cause  this deadly disease:

Radiation: If you experience high levels of radiation like those from radiation therapies and x-rays (repeated exposure) on a daily routine, you can probably damage your normal cells and increase your risk of developing leukemia, as well as cancers of the breast, thyroid, lung, stomach and other organs.

Ultraviolet (UV) Radiation: Long exposure in the sun too can be harmful. The UV radiations from the sun are directly linked to melanoma and other forms of skin cancer. These harmful rays of the sun not only cause premature aging and damage to your skin but many artificial sources of UV radiation, such as sun lamps and tanning booths, can also increase the risk of skin cancer. However, you can avoid the risk of skin cancer by wearing protective clothing and sunscreens and by avoiding prolonged exposure to the sun.

Viruses: It is to be noted that studies suggest that some viruses, including hepatitis B and C, human papillomaviruses(HPV), and the Epstein Barr virus, which causes infectious mononucleosis, have been associated with increased cancer risk.

Chemicals: Long term exposure to chemicals such as pesticides, uranium, nickel, asbestos, radon and benzene can also increase the risk of cancer. Such carcinogens can either act alone or in combination with another carcinogen, such as cigarette smoke, to increase the risk of cancer and other lung diseases.

Tobacco: If you are a chain smoker and experience regular exposure to tobacco smoke then you can be at high risk of getting lung cancer. It is believed that cigarette smokers are more likely to develop several other types of cancer like those of the mouth, larynx, esophagus, pancreas, bladder, kidney and cervix. Smoking a cigarette may also increase the risk of developing cancers of the stomach, liver, prostate, colon and rectum

Alcohol: Heavy Alcohol drinkers have an increased risk of cancers of the mouth, throat, esophagus, larynx and liver. Though, some studies also suggest that even moderate drinking may slightly increase the risk of breast cancer. In the year 2000, The American Cancer Society (ACS) estimated that about 171,000 cancer deaths were expected to be caused by tobacco use, and about 19,000 cancer deaths were to be related to excessive alcohol use, frequently in combination with tobacco use.