Some ancillary diagnostic markers, mainly immunohistochemical, have been investigated to facilitate BE diagnosis: proliferation markers such as Ki67, genetic mutations (p53, p16, Kras, APC, B catenin), some growth factors, cyclooxygenase 2 (COX-2), and alpha-methylacyl-CoA racemase (AMACR). This evidence concerns the gene PTGS2 and Barrett esophagus.