PTPN6 and central nervous system cancer: Decreased Shp1 expression and PTPN6 hypermethylation are linked to tumor staging, pathological differentiation, and poor survival in various cancers, including esophageal squamous cell carcinoma (ESCC) (198), endometrial carcinoma (EC) (199), high-grade glioma (HGG) (200), and NSCLC (201).