In human lung cancer cells, NRF2 regulates serine biosynthesis via activating transcription factor 4 (ATF4) and phosphoglycerate dehydrogenase (PHGDH) to support GSH and nucleotide production and coordinately activates the pentose phosphate pathway (PPP) to supply ribose for nucleic acid biosynthesis (29, 107). This evidence concerns the gene PHGDH and lung cancer.