Mondo Description Familial colon cancer is a cluster of colon cancer within a family. Most cases of colon cancer occur sporadically in people with little to no family history of the condition. Approximately 3-5% of colon cancer is considered 'hereditary' and is thought to be caused by an inherited predisposition tocolon cancer that is passed down through a family in an autosomal dominant or autosomal recessive manner. In some of these families, the underlying genetic cause is not known; however, many of these cases are caused by changes (mutations) in the APC , MYH , MLH1 , MSH2 , MSH6 , PMS2 , EPCAM , PTEN , STK11 , SMAD4 , BMPR1A , NTHL1 , POLE , and POLD1 genes (which are associated with hereditary cancer syndromes). An additional 10-30% of people diagnosed with colon cancer have a significant family history of the condition but have no identifiable mutation in a gene known to cause a hereditary predisposition to colon cancer. These clusters of colon cancer are likely due to a combination of gene(s) and other shared factors such as environment and lifestyle. High-risk cancer screening and other preventative measures such as prophylactic surgeries are typically recommended in people who have an increased risk for colon cancer based on their personal and/or family histories.