Pathogenesis of esophageal cancer from reflux esophagitis

The esophageal adenocarcinoma is one of the terminal manifestations of reflux esophagitis. However, reflux esophagitis per se is not a precancerous lesion. Some cases of reflux esophagi- tis develop squamous metaplasia continuously creeping from esophago-gastric junction, and they are defined as columnar-lined esophagus and diagnosed as Barrett's esophagus in Japan. In western countries, columnar-lined esophagus gaining intestinal metaplasia is called Barrett's esophagus because the term of Barrett's esophagus is used as a precancerous lesion. Some steps of genomic changes, e. g. p53, SMAD, may lead Barrett's esophagus into adenocarcinoma. Although the typical Barrett's esophagus is very rare in Japan, the preva- lence rate of short-segment Barrett's esophagus is extremely higher comparing with in western countries. The discrepancy may be caused by the differences of criteria of short- segment Barrett's esophagus. Large volume prospective studies are needed to clarify the malignant potentials of Barrett's esophagus diagnosed in Japan.