Infectious Agents Induce Wnt/β-Catenin Pathway Deregulation in Primary Liver Cancers

Interaction between infectious agents and liver tissue, as well as repeated and extreme biological events beyond adaptive capacities, may result in pathological conditions predisposing people to development of primary liver cancers (PLCs). In adults, PLCs mainly comprise hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA). Various infectious agents in the hepatic microenvironment can destabilize normal liver cell functions by modulating the Wnt/beta-catenin pathway components. Among them, hepatotropic viruses B, C, and D are involved in Wnt/beta-catenin signaling dysregulation. Other microbial agents, including oncogenic viruses such as Epstein-Barr virus (EBV) and human papilloma virus (HPV), bacteria, e.g., Mycoplasma hyorhinis and Salmonella Typhi, the protozoan parasite Toxoplasma gondii, the fungus Aspergillus flavus, and liver flukes such as Clonorchissinensis or Opisthorchis viverrini, may induce malignant transformation in hepatocytes or in target cells of the biliary tract through aberrant Wnt signaling activation. This review focuses on new insights into infectious agents implicated in the deregulation of Wnt signaling and PLC development. Since the Wnt/beta-catenin pathway is a driver of cancer following viral and bacterial infections, molecules inhibiting the complex axis of Wnt signaling could represent novel therapeutic approaches in PLC treatment.