Cancer is a group of diseases that results from abnormal cell growth. Normal cells reproduce themselves by dividing. When cells begin growing too rapidly, and without order, a tumor is created. Many tumors are benign (be-NINE), meaning they will stay confined to the part of the body where they formed and can usually be removed. Other tumors are malignant and 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. This process of metastasis (muh-tas-tuh-sus) can have fatal results. Cancer can be divided into four groups. Cancers that occur on the skin or an organ are called carcinomas (kar-si-noe-mahs). Those that occur in muscle tissue or bone are called sarcomas (sar-coe-mahs). Lymphomas (lim-foe-mas) are tumors of the lymphatic (lim-fat-ick) system, affecting lymph nodes in the neck, groin, armpits, liver, and spleen. Leukemias are cancers of the blood-making bone marrow. Many factors may cause cancer, especially exposure to carcinogens (car-sin-o-jins), such as smoking environmental contaminates, even sunlight. A high-fat diet and obesity may increase your risk, as well as having 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. For more information about cancer, contact your healthcare provider.