Over-expression of Anterior Gradient 3 Is Associated With Tumor Progression and Poor Survival in Gastric Cancer

Background/aim: Anterior gradient (AGR) proteins, including AGR1, AGR2, and AGR3, which are members of the protein disulfide isomerase family, have been reported as biomarkers for various carcinogenesis processes. Although AGR2 and AGR1 have been demonstrated to be associated with gastric cancer (GC) progression and poor survival, the effect of AGR3 on the progression and prognosis of GC remains unknown. Therefore, our study aimed to examine the expression and prognostic significance of AGR3 in patients with GC.

Patients and methods: We investigated 271 GC patients receiving curative surgery. Formalin-fixed and paraffin-embedded tissue blocks were obtained, and long-term survival analysis was performed. The expression of AGR3 in GC tissues was investigated by quantitative reverse transcription-polymerase chain reaction, western blotting, and immunohistochemistry.

Results: AGR3 was over-expressed in GC tissue compared with paired normal tissue at the mRNA and protein levels. AGR3 over-expression was significantly associated with larger tumor size, deeper tumor invasion, lymph node metastasis, and advanced tumor stage. The overall survival of patients with positive AGR3 expression was significantly lower than that of patients without positive AGR3 expression. Multivariate analysis demonstrated that AGR3 and age were independent prognostic factors associated with overall survival.

Conclusion: Over-expression of AGR3 was significantly associated with tumor progression and poor survival of GC patients. Therefore, AGR3 may be a novel biomarker and prognostic factor for GC.