Risk factors increase your likelihood of developing cancer. Scientists don't know exactly why normal cells become abnormal, but they know that contact with cancer-causing agents called carcinogens (kar-SIN-ah-jens) is a major culprit. Some risk factors are avoidable, while others can't be controlled. One of the most avoidable risk factors is tobacco. Smoking is linked with a number of cancers including cancer of the lung, bladder, mouth, and cervix. Smoking, chewing, and dipping tobacco are also the most common risk factors for oral cancer. Alcohol is the second leading avoidable risk factor associated with stomach, esophagus, breast, throat, oral, and liver cancers. A family history of cancer is one of the unavoidable risks. This is especially true in breast, prostate and colon cancer. If a close relative, particularly a parent or sibling, has had one of these cancera, your risk is automatically increased. Age is another unavoidable risk. The older you get, the more prone you are to developing some forms of cancer. Some environmental pollutants are also thought to act as carcinogens. Knowing which carcinogens are avoidable may reduce your risk of developing cancer. For more information about cancer risk factors, contact a healthcare professional.