We divided the cases for the two major NSCLC subtypes, lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC), in the TCGA into WIP1-high (the top 25%) and WIP1-low (the bottom 25%) groups, and compared the expression levels of the four ALDH1 isoforms (A1–A3 and B1) between the two groups. This evidence concerns the gene PPM1D and squamous cell lung carcinoma.