ALDH3A2 and esophageal squamous cell carcinoma: The core region of Module_1 mainly consisted of aldehyde dehydrogenase (ALDH) superfamily members, of which multiple genes, such as ALDH7A1, ALDH2, ALDH9A1, ALDH3A2, ALDH1A3 and ALDH3B2, were differentially expressed in ESCC (Figure 5B).