KEAP1 and neoplasm: The mutant loci often locate in the regions affecting the binding of Nrf2 to Keap1, which means the mutation of NFE2L2 gene usually decreases the binding affinity between Nrf2 and Keap1 and leads to the constant activation of Nrf2.29, 31, 38 In our study, the tumor tissue samples were collected by esophageal endoscopy and the gene sequencing was not applied due to the limited volume of tissue.