Causes of cancer

Causes of cancer. In most individual cases, the exact cause of cancer is unknown. It's likely that each case represents an interplay of several factors, which may include increased genetic susceptibility; environmental insults, such as chemical exposure or smoking cigarettes; lifestyle factors, including diet; and damage caused by infectious disease. Although they are not causes per se, a number of factors'including gender, race, age, and the health of the patient's immune system'can influence the development of cancer. When common causes for a type of cancer are discovered, this information can be very helpful in prevention and sometimes in treatment. For example, the link between overexposure to the sun and skin cancer is well known, and individuals can easily reduce their risk of skin cancer by avoiding sun tanning and sunburns. Alcohol is associated with an increased risk of cancer of the esophagus, mouth, pharynx, larynx, liver, breast, rectum, and pancreas.