ATF4 and cancer: Interestingly, when RBBP8 and ATF4 were costained in liver cancer samples, they showed a positive correlation throughout the tumor sections (Fig. 7L, M), and the ratio of ATF4 nucleus localization is also positively correlated with RBBP8 protein level (Fig. 7N), suggesting the involvement of RBBP8 in ATF4 signaling in human cancer cells both in vitro and in vivo.