PTEN and hereditary nonpolyposis colon cancer: Other risk factors include genetic factors such as hereditary nonpolyposis colorectal cancer (HNPCC, or Lynch syndrome) and Cowden syndrome, which is rare and in most cases related to a mutation in the phosphatase and tensin homologue deleted on chromosome 10 (PTEN) gene, located on chromosome 10q23.31 [19–22].