ATF4 and cancer: Furthermore, Nrf2 has a significant role in the regulation of cancer cell amino acid metabolism pertaining to the transcription of genes involved in the coding of phosphoserine aminotransferase (PSAT1) and Serine Hydroxymethyltransferase 2 (SHMT2), the key enzymatic protein reported to be involved in serine/glycine biosynthesis via ATF4 activation in NSCLC cancer cell [130].