C-met and hepatocyte growth factor expression in combined hepatocellular and cholangiocarcinoma

The membranous tyrosine kinase receptor c-met and its natural ligand hepatocyte growth factor are prominent mitogens, motogens and morphogens for hepatocytes and many other cell types in vitro as well as in vivo. To clarify the significance of the c-met/hepatocyte growth factor system in the development and spread of combined hepatocellular and cholangiocarcinoma, surgical specimen from 30 patients, consisting of 4 double cancers, 20 combined types and 6 mixed types, were examined immunohistochemically. Immunoreactivity for HGF was significantly correlated with the differentiation degree of cholangiocellular components, being highest in well and moderately differentiated and lowest in poorly differentiated components (p=0.0119). No significant association was observed between expression of c-met or HGF and the presence of liver cirrhosis, vascular invasion, perineural invasion, lymphatic permeation, intrahepatic metastasis or lymph node metastasis. HGF may have an important impact on the differentiation of certain cHCC-CC. Other clinicopathologic factors related to tumor development and spread may not be influenced by c-met or HGF, at least not on the protein level.