PTCH1 and esophageal squamous cell carcinoma: Many other mutated genes have been described in ESCC, such as DCDC1, FAM135B, ADAM29, FAT2, TGFBR2, NAV3, TENM3, TET2, PTCH1, USP8, RIPK4, PBRM1 and VANGL1. Despite some studies having characterized them well, their role in ESCC is still poorly understood [26,27,28,30,31,33,46].