MAN1A1 and neoplasm: Extended high-mannose N-glycans promote metastasis of cholangiocarcinoma in mice membrane proteins via down-regulation of MAN1A1, as shown in MAN1A1-overexpressing KKU-213AL5 cells [38], while M6, M9, and A3F structures may be associated with tumor progression in human cholangiocarcinoma [39].