Monday, 19 September 2011

Cancer

Varieties of cancer:
Carcinomas, the most common types of cancer, arise from the cells that cover external and internal body surfaces. Lung, breast, and colon are the most frequent cancers of this type in the United States.
Sarcomas are cancers arising from cells found in the supporting tissues of the body such as bone, cartilage, fat, connective tissue, and muscle.
Lymphomas are cancers that arise in the lymph nodes and tissues of the body’s immune system.
Leukemias are cancers of the immature blood cells that grow in the bone marrow and tend to accumulate in large numbers in the bloodstream.
Prefixes used in naming cancers
o adeno = gland (adenocarcinoma)
o chondro = cartilage (chrondroma)
o erythro = red blood cell (erythroblastoma)
o hemangio = blood vessels (hemangiosarcoma)
o hepato = liver (hepatocarcinoma)
o lipo = fat (lipoma)
o lymph/o or a/ o = lymphocyte (lymphoblastoma, lymphangioma)
o melano = pigment cell (melanocytoma)
o myelo = bone marrow (myelosarcoma)
o myo = muscle (myocytoma)
o osteo = bone (osteoma, osteosarcoma)
Loss of Normal Growth Control
Cancer arises from a loss of normal growth control. In normal tissues, the rates of new cell growth and old cell death are kept in balance. In cancer, this balance is disrupted. This disruption can result from uncontrolled cell growth or loss of a cell’s ability to undergo “apoptosis.” Apoptosis, or “cell suicide,” is the mechanism by which old or damaged cells normally self-destruct.
Cancers are capable of spreading through the body by two mechanisms: invasion and metastasis. Invasion refers to the direct migration and penetration by cancer cells into neighboring tissues. Metastasis refers to the ability of cancer cells to penetrate into lymphatic and blood vessels, circulate through the bloodstream, and then invade normal tissues elsewhere in the body.

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