ABSTRACT
PURPOSE: Gastric cancer is the second leading cause of cancer-related death worldwide. Although surgery is the standard curative treatment for gastric cancer, relapse occurs in a large number of patients, except in the case of early diagnosed gastric cancer. Following previous studies that identified endoplasmic reticulum oxidoreductin 1-α (ERO1L) as a potential marker for gastric cancer, we investigated the functional role of ERO1L in gastric cancer. MATERIALS AND METHODS: For validation of microarray data, the mRNA expression level of ERO1L was measured by quantitative real-time reverse transcription polymerase chain reaction in 56 independent stage III gastric cancer patients. Immunohistochemical staining was performed to examine the protein expression level of ERO1L in 231 gastric cancer patients. Correlation between gene expression and cancer prognosis was evaluated. RESULTS: Patients with high ERO1L expression had poorer survival than those with low expression (p < 0.01). Functional assays demonstrated that ERO1L knockdown inhibited cell proliferation, migration, invasion, and chemoresistance. In addition, involvement of inactivation of Akt and JNK signaling in molecular mechanisms of ERO1L inhibition was demonstrated. CONCLUSION: High expression of ERO1L is associated with poor prognosis of patients with gastric cancer. These results indicate that ERO1L expression may be a clinically promising therapeutic target for prevention of gastric cancer.