Deregulation of signaling pathways involved in sorafenib resistance of hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the most common neoplasms worldwide. Hepatocarcinogenesis is associated with deregulation of the cell signaling thus targeted therapy can decelerate HCC progression by specific inhibition of alternated signaling cascades. Sorafenib is the only multitarget drug approved for HCC treatment that blocks several crucial oncogenic signaling pathways thus suppressing tumor growth, metastasis and providing survival benefit for subset of patients sensitive to sorafenib. Compensatory activation of other tumorigenic mechanisms may lead to decrease of HCC sensitivity to sorafenib. HCC are heterogenic tumors of epithelial origin, and presence of low-differentiated subpopulations of cancer stem cells or dedifferentiated fibroblastoid cells, that are less sensitive to sorafenib due to resistance to growth-inhibitory action of the drug, promotes HCC resistance to sorafenib. Analysis of the expression profile of genes encoding tissue-specific proteins, components of cell junctions, stem cell and mesenchymal markers can reveal sorafenib-resistant populations in HCC and identify signaling pathways that reduce response to sorafenib. Identification of individual sorafenib resistance mechanisms may be useful for rational choice of an appropriate combination of targeted drugs for retardation of HCC progression and improving the efficacy of therapy