Normal cells reproduce themselves and divide in two. When cells begin growing too rapidly, and without order, a tumor is created. Some tumors, however, are malignant tumors that invade surrounding tissue, destroying healthy cells. If unchecked, cells may break off and spread through the bloodstream to other parts of the body and create new tumors. Cancer can be divided into four groups.
Leukemias are cancers of the blood-making bone marrow.
Many factors may cause cancer. Scientists have found that smoking is associated with several cancers, and that high-fat diets and obesity may also increase your risk. Excessive exposure to sunlight is a factor in many skin cancers. If you have a history of cancer in your family, talk to your doctor about the warning signs of cancer. Early detection is the key to effective treatment.