ALDH9A1 and esophageal squamous cell carcinoma: Notably, 18 of the 20 downregulated DE-TrpGs (ALDH9A1, ALDH3A2, ADH1B, AOX1, MAOA, ECHS1, ALDH2, ACAT1, HAAO, ALDH7A1, HADHA, AKR1A1, CYP4X1, INMT, CYP2U1, CAT, HADH, and NMNAT1) showed significantly reduced expression specifically in ESCC fibroblasts compared to their normal counterparts.