Cancer Definition
The uncontrolled growth of abnormal cells derived from normal tissues, which eventually can cause death by spreading from the site of origin to other sites. There are an estimated 200 different kinds of cancers. Cancers that arise in epithelial cells (cells that form the outer surface of the body, line the body cavities, and line the principal tubes and passageways leading to the exterior) are called carcinomas; and those from mesenchymal tissues (connective tissues, blood and blood vessels, and the lymphatic system), are classed as sarcomas. Leukemias are also classed as malignant (cancerous and resisting treatment) growths. |
