Also in accordance with our discovery, other reports suggested that GCN2/ATF4 signaling plays a role in the survival and proliferation of cell lines and cancer xenografts under suboptimal growth conditions as a result of amino acid/nutrient deprivation and unbalanced protein synthesis (Harding et al., 2019; Nakamura et al., 2018; Rajanala et al., 2019; Ye et al., 2010). Here, ATF4 is linked to cancer.