Combined hepatocellular-cholangiocarcinomas exhibit progenitor features and activation of Wnt and TGFbeta signaling pathways

ABSTRACT: Primary liver tumours include hepatocellular carcinomas (HCC), cholangiocarcinomas (CC) and a group of rare tumours exhibiting biliary and hepatocytic differentiation called combined hepatocholangiocarcinomas (cHCC-CC). To better define this latter group, we take advantage of a series of these tumours based on their morphological characteristics and we performed transcriptional analysis allowing thereafter global comparison with published data. We show that most cHCC-CCs express progenitor cell traits, are committed to biliary lineage and are mainly associated to the activation of Wnt/beta-catenin and TGFbeta signalling pathways. Wnt/beta-catenin pathway activation in cHCC-CC is evidenced by the expression of both its direct targets such as LEF1 and EPCAM. In addition, extracellular matrix (ECM) genes and ECM-remodelling genes which are upon the control of TGF profibrotic program were found up-regulated in cHCC-CC. Interestingly, we show that CC and most cHCC-CC share characteristics associated to a subtype of poorly differentiated HCC suggesting that these tumours could originate from a stem/progenitor cell. The plasticity of these cells may explain the phenotypical heterogeneity of these tumors with the maintenance of some hepatocellular differentiation features such as albumin expression. Interestingly, this is shared by at least one third of CC, raising the hypothesis of a potential continuum between CC, cHCC-CC and poorly differentiated HCC. Patients serie include 3 intra-hepatic CC, 7 typical HCC and 20 cHCC-CC that was used for microarray hybridisation. All these tumours did not show any mutation of the beta-catenin gene. The degree of hepatic fibrosis of the non-cancerous liver was graded according to the METAVIR classification. Paraffin sections were processed as described previously. Immunohistochemistry was done on standard slides for the series.

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PROVIDER: S-DIXA-D-1118 | biostudies-other |

REPOSITORIES: biostudies-other