ALDH2 and cancer: To take a step back, we analyze all the available transcriptomic data (GSE19713 [123], GSE23806 [124–126], GSE28799 [127], GSE35603 [128], GSE67966) of different cancer stem cells in Gene Expression Omnibus (GEO) [129, 130] using platform GPL570 [131] with ALDH1A1 and ALDH2 expression against 5-year overall survival data in different cancers documented in literature (Supplementary Table 1), if we consider ALDH1A1 and ALDH2 expression somewhat similar to their activities.