G6PD and lung cancer: Expression of PPP enzymes such as G6P dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (PGD), and transketolase (TKT) was directly regulated by NRF2 in lung cancer cells, and NRF2 overexpression redirected cell metabolism to PPP-mediated purine nucleotide synthesis [28].