PTEN and hereditary nonpolyposis colon cancer: Additional study reported that somatic genetic and epigenetic inactivation of PTEN was involved in as high as 93% of sporadic endometrial carcinomas, which was the most frequent extracolonic cancer in patients with hereditary nonpolyposis colon cancer (HNPCC) syndrome, suggesting that PTEN may play a significant pathogenic role in both HNPCC and sporadic endometrial carcinogenesis [45].