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:
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.