Causes of Cancer

The vast majority of cancers – as many as 80% -- are considered sporadic, or without a clear genetic predisposition. For some reason, normal genes begin to mutate (change), multiplying rapidly and becoming malignant.

Researchers believe several environmental influences that may cause these gene mutations to occur. In fact, a large number of cancers are preventable because most of these factors can be controlled with healthy lifestyle choices.

Environmental causes of cancer can include:

• Age. Cancer occurs most frequently in people aged 50 or older. 
• Diet. High-fat, high-cholesterol diets are proven risk factors for several types of cancer, particularly colon cancer.
• Obesity. Research indicates obesity may be a contributing factor to some cancers, although no clear link has been established as yet.
• Smoking. Smoking of tobacco greatly boosts the risk of lung cancer, even among non-smokers forced to inhale secondhand smoke. Other tobacco products, including pipes, chewing tobacco and snuff, are linked to mouth, tongue and throat cancers.
• Long-term exposure to chemicals.
• Exposure to high levels of radiation.
• Harmful ultraviolet rays from the sun. UV light has been linked directly to the formation of melanoma and other skin cancers.
• Some viruses, including Hepatitis B and C, Human Papilloma Virus (HPV) and Epstein-Barr virus (EBV), have been associated with increased cancer risk. 
• Immune system diseases such as AIDS. Some immune-system diseases can make the body more susceptible to cancer.

Most of the remaining 20 percent of cancers are hereditary, meaning the abnormal gene responsible for causing the cancer is passed from parent to child, posing a greater risk for that type of cancer in all descendants of the family. It is important to note, however, that carrying a cancer-causing gene does not mean you will automatically develop cancer.