JAK2 and Barrett esophagus: In obese subjects the combination of high leptin and low adiponectin levels may also increase the risk of Barrett’s esophagus [85,86,87,88,89,90] and esophageal adenocarcinoma by enhanced cell proliferation and reduced apoptosis via extracellular signal-regulated kinase (ERK), p38 MAPK, phosphatidylinositol 3′-kinase/Akt, and Janus kinase-2 (JAK2)-dependent activation of cyclooxygenase-2 (COX-2) and prostaglandin E2 (PGE2).