Kazumori et al. found that BAs activate the expression of CDX1 in immature esophageal keratinocytes and illustrated how CDX1 interacts with CDX2 and how that interaction works, stimulating the development of BE by binding directly to each other’s promoters, leading to upregulation of BE (Kazumori et al., 2009). The gene discussed is CDX1; the disease is Barrett esophagus.