As you most likely know cancer is a very mysterious and deadly disease, but what is cancer really? Cancer is a disease which forms when abnormal cells divide without control. These cells are able to invade other tissues. There are over one hundred different types of cancer. Each different type of cancer is classified by the type of cell that is initially affected. Although there are many great advancements of technology to treat and prevent cancer, cancer is still the number one leading cause of death for people under the age of eighty five. In fact, in the United States, one out of every four people die from cancer. Cancer is a very complicated disease which has not yet been fully understood. When the abnormal cells divide without control they form lumps or masses of tissue known as tumors (except in the case of leukemia where cancer prohibits nomal blood function by abnormal cell division in the blood stream). When we are born we have normal cells that continually grow until adulthood. We also have abnormal cells in our body. As we get older our normal cells stop dividing and only divide to replace dead or damaged cells. The abnormal cells in our body continue to divide even into adulthood and form cancerous cells. Most cancers develop into tumors, although all tumors are not created in the body by the abnormal cells. Tumors that are not created by abnormal cells are not cancerous. These tumors will not affect the body in as harmful ways as cancerous tumors would. These non cancerous tumors are known as benign tumors. Cancer has many possible causes because it is a complex group of diseases. Some forms of cancer can run in your family. You can inherit a gene of cancer but even if it is inherited it does not mean you will get cancer. A genetic alternative that is linked to cancer is just a risk factor. Another cause of cancer is the use or exposure of carcinogens. Tobacco, asbestos, compounds in a car exhaust fumes, arsenic, the sun, and radiation such as gamma and x-rays. When our bodies are exposed to these substances, free radicals are formed that try to steal electrons from other molecules in the body. These free radicals damage cells and affect their ability to function normally. These products contain over seven thousand different chemicals and of these chemicals, sixty are known to cause cancer. Eighty seven percent of lung cancer deaths and thirty percent of all cancer deaths are caused by smoking. Exposure to too much sun can also cause cancer and ultraviolet radiation from the sun or a tanning bed causes the cells to grow abnormally and out of control. Another cause is obesity. In fact, the American Cancer Society Prevention II showed significant increases in cancer occurrence in people who are most overweight. There are many different cancer treatments but the three most common are surgery, chemotherapy, and radiation. Surgery is normally the first option of treatment if the tumor can be removed from the body. Sometimes only parts of the tumor can be removed. Chemotherapy uses drugs to kill cancer cells. Doctors enter the medicine through an IV or the patient can take the medicine by mouth. The drugs travel through the body in the bloodstream, reaching cancer cells that have spread from the tumor to any other parts of the body. Radiation therapy kills the cancer cells or shrinks the tumor by using high energy rays. There are two different types of radiation therapy known as external or internal radiation. External radiation is painless but side effects may occur. Internal radiation is from radioactive material put into the tumor. Cancer is not yet curable, the phrase "cure for cancer" is nonsense; there will not be any single cure for cancer because there