When investigating the levels of eNOS and phosphorylated eNOS (P-eNOS), together with the regulators VEGFR3, VEGFC, EphA3 and ephrin1, in a hamster model of induced CCA and human CCA, it was seen that in the latter intense immunohistochemical staining of all examined proteins was associated with metastasis. This evidence concerns the gene FLT4 and cholangiocarcinoma.