RNF41 and hepatocellular carcinoma: A schematic model of HCC progression caused by CACYBP overexpression is shown in Figure 6D. In HCC cells, in the absence of enough RNF41, elevated CACYBP induces the phosphorylation of P27Kip1 at Ser10 and enhances its cytoplasmic retention, leading to rapid cell cycle progression and uncontrolled cell growth.