To test whether the decrease in the NAD+/NADH ratio was caused by the GSH/DHLA-dependent NAD+-reduction activity of ALDH1A1 that we characterized in vitro, we ectopically expressed different mutants of ALDH1A1 in H1299 cells, a non-small cell lung cancer cell line that does not express endogenous ALDH1A1 (Figure 5A). The gene discussed is ALDH1A1; the disease is non-small cell lung carcinoma.