Alterations of MMP-9 and glutathione S-transferase expressions in the esophagitis-Barrett's metaplasia-dysplasia-adenocarcinoma sequence of the esophagus

Background: Barrett's esophagus is the main precancerous condition for development of esophageal adenocarcinoma. Glutathione S-transferase (GST) plays a part in prevention of cancer by detoxifying numerous potentially carcinogenic compounds. Matrix metalloproteinases play an important role in extracellular matrix remodelling during the process of tumor progression. Decreased GST activity has been reported in Barrett's dysplasia and adenocarcinoma and increased levels of matrix metalloproteinase-9 (MMP-9) have been observed in esophageal squamous cell carcinoma, but their role in early stages of esophageal carcin…