Development and spread of cancer
Courtesy of Microsoft Corporation. Extracted from Microsoft Encarta '97
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Lung cancer begind when epithelial cells lining the respiratory tract
start to reproduce in an uncontroled fashion. These cells invade
surrounding tissue, forming a mass a tumor and, when hardened, a
carcinorna. Cancerous cells may penatrate blood and lymph vessels,to be carried through the body until they reach a juncture through which they cannot pass. At this point, they lodge and new tumors form. Metastasis, the spreading of cancer from its original location to other parts of the body,is the disease's most destructive characteristic. |