There are two well-researched genetic causes of Colorectal Cancer. These genetic causes include: Hereditary Non-polyposis Colorectal Cancer and Familial Adenomatous Polyposis. While those diseases are passed down from one generation to another, most causes of Colorectal Cancer occur because of gene mutations that are acquired during one’s lifetime. These acquired mutations only affect the individual and are not passed down from one generation to the next.
Hereditary Non-Polyposis Colon Cancer (HNPCC), also called Lynch Syndrome, is a genetic disease that affects generations. There are specific genes within the individual’s DNA that have been damaged. When that specific DNA repair enzyme is not able to fix those mutations, then they are passed on to the individual and can actually result in cancer formation. It is the specific genes that can contribute to the development of Colorectal Cancer.
Familial Adenomatous Polyposis (FAP) are also inherited gene mutations that are passed from one generation to the next generation. These changes directly affect a tumor suppressor gene known as the APC gene. The tumor suppressor gene, in its normal function, is responsible for making sure that the cells do not outlive their normal life cycle. When this APC gene is mutated, then there is not any regulation to the cell cycle and the result is cells that overgrow. These overgrowing cells result in the development of polyps rapidly and in large quantities. These polyps grow within the large intestine. Because of these mutations, the patient is at very high risk for developing Colorectal Cancer (American Cancer Society, 2017).
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While those forms of Colorectal Cancer occur because of genetic disposition, the average individual does not get it through those means. Most often Colon or Rectal Cancers occur because of acquired mutations to the genome over a lifespan. There are many risk factors that can contribute to the development of these mutations over an individual’s lifespan.
Those risk factors include the following: obesity, sedentary lifestyle or physical inactivity, diets with high proportions of red meats and processed meats, smoking, alcohol, age greater than 50 years; past medical history of polyps within the colon or rectum; past medical history of colon or rectal cancer; past medical history of inflammatory bowel disease such as Crohn’s disease and/or Ulcerative Colitis; a family history of polyps and/or Colorectal Cancer; genetic disposition to FAP or HNPCC; and Diabetes Mellitus, Type II.
While these are just risk factors, they can contribute to the mutations that may occur within one’s own genome. These mutations may affect the cells regulation system; thus increasing the individual’s risk for developing polyps and Colorectal Cancer over a period of time
