NFE2L2 and esophageal cancer: The role of NRF2 in tumorigenesis has been identified in a broad spectrum of tumor types, such as ovarian, lung, breast, skin, and esophageal cancer.31 Some natural compounds, such as alkaloid trigonelline, which renders pancreatic cancer cells more susceptible to apoptosis, have been identified as NRF2 inhibitors.32 Our data suggest that Cu-I might be a novel inhibitor of the NRF2 pathway.