Cancer (medical term: malignant neoplasm) is caused when cells display uncontrolled growth (division beyond the normal limits). When cancer when abnormal growth of a otherwise normal cell begins to attack and invade other normal cells destroying surrounding tissues. There are several kinds of cancers but there are two major differences. One type is benign - meaning it wont kill you. The other kind is malignant - which means it can kill you if not treated. Another common cancer term is metastasis. Metastasis is the spreading of the tumor or the cancer to different parts of the body - often through the lymphatic system. Cancer may affect people at all ages, even fetuses, but the risk for most varieties increases with age. According to the American Cancer Society, 7.6 million people died from cancer and was responsible for 13% of all deaths in 2007.