Colon Cancer

In just one year alone, more than 100,000 Americans will get colon cancer. The colon is the main part of the large intestine. It takes more than one somatic mutation to produce a full-fledged cancer cell. Colon cancer begins when an oncogene arises or is activated through mutation, causing unusually frequent division of apparently normal cells in the colon lining. Later, additional DNA mutations cause the growth of a small benign tumor in the colon wall. Still more mutations eventually lead to formation of a spreading tumor. The requirement for several mutations explains why cancers can take a long time to develop. The actual number of mutations is usually around six. Multiple changes must occur at the DNA level for a cell to become fully cancerous. Once a cancer promoting mutation occurs, it is passed to all the descendants of the cell carrying it. The fact that more than one somatic mutation is generally needed to produce a full-fledged cancer cell may help explain why the incidence of cancer increases with age.

 

 

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