| Definition: Cancer |
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Cancer is a disease in which abnormal cells divide uncontrollably to form a mass, or
tumor. These abnormal cells can spread, or metastasize, to other parts of the body.
Cancer develops in stages over a period of years:
Initiation -- Exposure to a carcinogen damages the genetic material.
Promotion -- The damaged cells are stimulated to develop by cancer-promoting
substances like hormones.
Progression -- The tumor develops, becomes more invasive and spreads to other
parts of the body.
tumor. These abnormal cells can spread, or metastasize, to other parts of the body.
Cancer develops in stages over a period of years:
Initiation -- Exposure to a carcinogen damages the genetic material.
Promotion -- The damaged cells are stimulated to develop by cancer-promoting
substances like hormones.
Progression -- The tumor develops, becomes more invasive and spreads to other
parts of the body.
