AKR1C2 and esophageal squamous cell carcinoma: To investigate whether the up‐regulation of AKR1C2 was a common event in ESCC, the mRNA expression of AKR1C2 in 43 paired samples were detected by RT‐qPCR and was found to be elevated in most of ESCC tissues compared to the corresponding adjacent normal tissues (P < .001; Figure 1C).