Aberrant glycosylations in CCA (e.g., mucin MUC5AC, MUC1, CCA-CA, carbohydrate antigen 19-9 (CA19-9), and CA-S27) have been used as proxies for CCA diagnosis as their altered expressions are correlated with the progression of CCA [4]. Here, MUC5AC is linked to cholangiocarcinoma.