CHST4 and bladder transitional cell carcinoma: CHST4 expression is also elevated in gastric cancer tissues (22), urothelial bladder carcinoma (23), cholangiolocellular carcinoma (24), and Opisthorchis viverrini (OV)-related intrahepatic cholangiocarcinoma (25), and the CHST4 promoter is hypermethylated in HBV-HCC (26).