Combining the findings of higher CES2 expression scores in tumoral stroma of pCCA and dCCA and the subtype-specific survival benefit of higher CES2 expression in dCCA and in pCCA, one is tempted to speculate on the impact of CES2 expression in tumoral stroma on the tumor – immune system interaction in extrahepatic CCA, although stromal CES2-expression levels were not significantly associated with survival in CCA and subtypes. This evidence concerns the gene CES2 and cholangiocarcinoma.