Subpathway representing ER-stress-associated genes regulated by NFE2L2 (NRF2). Activating transcription factor 4 (ATF4) is a stress-induced transcription factor that is frequently upregulated in cancer cells. ATF4 controls the expression of a wide range of adaptive genes that allow cells to endure periods of stress, such as hypoxia or amino acid limitation. However, under persistent stress conditions, ATF4 promotes the induction of apoptosis (Wortel et al, 2017). ATF4 is also known to regulate serine and glycine biosynthesis in NSCLC (Denicola et al, 2016)