PTPN6 and esophageal squamous cell carcinoma: High promoter methylation of ESCC suppressor genes, such as p16 [149], RASSF5A [150], SULT2B1 [151], SEMA3B [152], PTPN6 [153] and Bin1 [154] can lead to tumor suppressor gene silencing and cancer cell activation and can be used as a predictor of clinical outcome after radical resection in ESCC patients.