Expression of early growth response-1 in human gastric cancer and its relationship with tumor cell behaviors and prognosis.

The early growth response-1 (Egr-1) is crucial in many cell regulatory processes related to the progression of human cancers. Its overexpression has been demonstrated in variable human cancers and may have prognostic significance. The aims of this current study were to evaluate whether Egr-1 affects invasive and oncogenic phenotypes of human gastric cancer cells, and to examine the relationships between its expression and various clinicopathological parameters, including survival in human gastric cancer patients. We investigated the biologic role of Egr-1 in tumor cell behavior by using a small interfering RNA in human gastric cancer cell lines, AGS and TMK1. The expression of Egr-1 by reverse transcription-polymerase chain reaction (RT-PCR), Western blotting and immunohistochemistry was investigated in human gastric cancer tissues. The knockdown of Egr-1 suppressed tumor cell migration and invasion in AGS and TMK1 cells. Egr-1 expression was significantly increased in human gastric cancer and metastatic lymph node tissues compared to the normal gastric mucosa and non-metastatic lymph node tissues. Positive expression of Egr-1 was significantly associated with tumor size, depth of invasion, lymph node metastasis, tumor stage and poor survival. These results indicate that Egr-1 is associated with human gastric cancer progression through the alteration of tumor cell behavior, such as migration and invasion. Egr-1 expression may help in predicting the clinical outcomes of human gastric cancer patients.