ATF4 and hepatocellular carcinoma: We confirmed that both RBBP8 and ATF4 were highly expressed in the Ki67-positive regions and positive cells in HCC tissues (Fig. 7), and discovered that RBBP8 protein expression level was significantly correlated with ATF4, supporting the hypothesis that RBBP8 is required for ATF4 activation and contributes to the progression of liver cancer.