Cancer is a collection of many diseases that all involve growth of abnormal cells. The body is made up of many types of cells. Normally, cells grow, divide, and then die. Sometimes, cells mutate (change). They begin to grow and divide more quickly than normal cells. Rather than dying, these abnormal cells clump together to form tumors.

Sometimes these tumors are benign (not cancer). But if the cells in these tumors are cancerous (malignant), they can invade and kill your body’s healthy tissues. From these tumors, cancer cells can metastasize (spread) and form new tumors in other parts of the body. Cells in benign tumors do not spread to other parts of the body.