In order to test whether miR-200a could directly regulate Keap1 by binding to its 3′-UTR in ESCC cells, the Keap1 3′-UTR was cloned into the pMiR-Report vector, downstream the luciferase gene (pMiR-Report/Keap1 3′-UTR-wt, abbreviated to Keap1 3′-UTR-wt). Here, KEAP1 is linked to esophageal squamous cell carcinoma.