SOX2 and hepatocellular carcinoma: However, given that UBR5 might have other client proteins, such as SOX2, p38, and Bcl-2 [8, 37], and the β-catenin signaling pathway has other negative regulators, such as APC, CKI-α, and GSK-3β [38], future studies regarding other UBR5/β-catenin-regulated signaling pathways and molecules involved in HCC tumorigenesis are warranted.