Published online Jun 28, 2017. doi: 10.3748/wjg.v23.i24.4330
Peer-review started: February 10, 2017
First decision: March 16, 2017
Revised: April 13, 2017
Accepted: May 19, 2017
Article in press: May 19, 2017
Published online: June 28, 2017
Processing time: 148 Days and 6.2 Hours
The prognosis for patients who are diagnosed with advanced stage hepatocellular carcinoma (HCC) is poor because there are few treatment options. Recent research has focused on the identification of novel molecular entities that can be targeted to inhibit oncogenic signals that are involved in the carcinogenesis, proliferation and progression of HCC. Among all of the pathways that are involved in the development of HCC, Hedgehog (HH) signalling has demonstrated a substantial role in hepatocarcinogenesis and HCC progression. HH plays a physiological role in embryogenesis, through the induction of the differentiation of hepatocytes from endodermal progenitors. The re-activation of the HH pathway in chronic damaged liver is a mechanism of fibrotic degeneration and is implicated in various stages of HCC development. HH activation sustains the sub-population of immature liver epithelial cells that are involved in the pathogenesis of cirrhosis and HCC, and HH itself is a mediator of the alcohol-derived malignant transformation of liver cells. High levels of expression of HH protein markers in liver tumour tissues are correlated with aggressive histological and biological features and a poor clinical outcome. In vitro and in vivo inhibition models of the HH pathway confirm that HH is essential in maintaining tumour growth, metastasis and a mesenchymal phenotype.
Core tip: The hedgehog (HH) pathway is involved in the embryonic development of liver, and its reactivation plays a substantial role in sustaining cancer cell growth and progression in hepatocellular carcinoma (HCC). In hepatocarcinogenesis, HH signalling is required for differentiation, proliferation and polarity of liver embryonic cells. High levels of expression of HH components in HCC tissues correlate with mesenchymal properties and maintain the proliferation of cancer stem cells, which is a dynamic source of malignant cells in HCC progression. Current data on HH inhibition in preclinical models further confirm the role of HH and deserve future investigations in a clinical setting.