Next, we found that the mRNA expression of downstream target genes of the KEAP1/NRF2 pathway, such as GCLC, GCLM, TXN, TXNRD, HO1, NQO1, GSR, and G6PD, which encode detoxifying enzymes and antioxidant proteins, were significantly higher in KEAP1 mutant cell lines than in wild-type (WT) lung cancer cells by real-time polymerase chain reaction (PCR), but the mRNA expression of NRF2 showed no significant difference between lung cancer cell lines with and without KEAP1 mutation (Fig. 1b). This evidence concerns the gene GCLM and lung cancer.