ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of Helicobacter pylori-encoded CagA on biological behavior of gastric adenocarcinoma AGS cells.</p><p><b>METHODS</b>With experiment-control system of the wild-type CagA positive strain and isogenic CagA negative mutant strain of Helicobacter pyroli (Hp) were used as control and experimental groups, respectively. The cell contact, migration and invasion were examined by light and electron microscopy and invasion assay.</p><p><b>RESULTS</b>The AGS cells infected by Hp strain with positive wild-type CagA showed more severely changed tight junction, wider intercellular space, loss of cell contacts, and higher migrating and invasive ability.</p><p><b>CONCLUSION</b>Hp CagA may lead to loss of cell contacting and higher migrating and invading ability of gastic cells, and accelerates the malignant progress of tumor.</p>