Cancer is an uncontrolled growth of cells that can occur in any tissue in the body.
All cancers occur as a result of damage or changes in the genes of a cell.
Most often several changes in different genes contribute to cause a cancer to develop and progress. Cancers can be described as either benign or malignant. Benign cancers tend to stay in a single part of the body without spreading. This process of spreading from an original tumor to another part of the body is known as metastasis. A tumor can metastasize through the blood stream or through the lymphatic vessels of the body.