To determine which AKR1 isoenzyme was elevated in ESCC cells after EDHB treatment, KYSE 180 and KYSE 510 cells were treated with EDHB for 48 h, and the protein levels of AKR1C1/C2, AKR1C3, AKR1B1, AKR1A1, and AKR1B10 were then quantitatively analyzed by MRM. Here, AKR1C1 is linked to esophageal squamous cell carcinoma.