The body is made up of many kinds of cells. Normally, cells grow, divide, and die. Sometimes, cells change and begin to grow and divide more quickly than normal cells. Rather than dying, these abnormal cells clump together to form tumors. If these tumors are cancerous, they can invade and kill your body's healthy tissues. From these tumors, cancer cells can spread and form new tumors in other parts of the body. By contrast, no cancerous tumors do not spread to other parts of the body.