In the present study, we found that the ability of the antioxidative stress response mediated by activation of the KEAP1/NRF2 pathway is higher in lung cancer cell lines with KEAP1 mutation (A549, NCI-H460, NCI-H838) than in lung cancer cell lines without KEAP1 mutation (NCI-H1299, NCI-H292, 95D, and SPCA1). The gene discussed is ATP2C1; the disease is lung cancer.