CTNNB1 and hepatocellular carcinoma: These studies have led to propose a classification of HCCs in three classes: a WNT subclass involving about 25% of HCC cases and characterized by recurrent CTNNB1 mutations and HCV etiology; a proliferation subclass involving about 50% of HCC cases and subdivided into two subgroups (S1-TGF-beta and S2-EpCAM-positive); an inflammation/interferon subclass involving about 25% of HCC cases [24].