ALDH2 and esophageal squamous cell carcinoma: In this study, we determined that the ESCC cell lines TE11 and TE14 have heterozygous (ALDH2*1/ALDH2*2) ALDH2 alleles while all PDOs (ESC2, ESC3, HSC1-3) carry homozygous (ALDH2*1/ALDH2*1) wild-type ALDH2 alleles (Supplementary Table S1).