ALDH2 and neoplasm: Based on the analysis of the HPA and CPTAC databases, we found that the protein expression levels of PPAT, KYNU, PSPH, ALDH2, and MIF evaluated by IHC in LUAD tumor tissues were consistent with the mRNA expression levels of each molecule; that is, high expression of PPAT, KYNU, PSPH, and MIF, as well as low ALDH2 expression, was observed in tumor tissues compared with those in the adjacent non-neoplastic lung tissues (Supplementary Figures 4A, B).