The present study did not focus on the predisposition to esophageal cancer with the disruption of circadian-clock gene expression in human subjects because, although Barrett’s esophagus is associated with severe GERD and with an increased risk of esophageal adenocarcinoma, most patients with Barrett’s esophagus do not develop esophageal cancer2. Here, CLOCK is linked to esophageal adenocarcinoma.