What Is Cancer?
Most cells in our body grow and die in a controlled or “programmed” way. When cells lose this normal program, they become cancerous. That is, they grow and divide without limits. As these abnormal cells grow, they often accumulate into a mass (tumor). When a tumor is cancerous, it is called malignant. When a tumor is not cancerous, it is called benign. Tumors can arise anywhere in the body. It is the body site and the tissue of origin that determine the main categories of cancers.