In cancer, abnormal cells grow out of control. Many factors can influence a person's risk for cancer. Heredity accounts for about 10 percent of all cancers. Viruses may cause certain leukemias and lymphomas, cancer of the nose and pharynx, liver cancer, and cervical cancer. It also is thought that about 5 percent of all cancers might be caused by radiation, including medical, occupational, and environmental exposures.
Many chemicals used in industry also are carcinogens.
Smoking, excessive exposure to sun, over use of alcohol, and a high-fat diet also can increase the risk of developing some types of cancer. A. Contact your health care provider and discuss your concerns. If appropriate, he or she may suggest that you make an appointment for further evaluation. You know your body better than anyone, so you should screen yourself for the changes described above. Watch for changes in size, color, number, and thickness of moles.