Patients with the following hereditary diseases are susceptible to EC development: Cowden’s disease, Peutz–Jeghers syndrome, and Lynch syndrome, which are caused by germline mutations in PTEN (Blumenthal and Dennis, 2008), LKB1 (Hearle et al., 2006), and mismatch repair genes (Meyer et al., 2009), respectively. This evidence concerns the gene PTEN and Cowden disease.