Decreased expression of Sox7 correlates with the upregulation of the Wnt/β-catenin signaling pathway and the poor survival of gastric cancer patients

Sox7 is a tumor suppressor gene that plays an important role in the inhibition and progression of cancer. In the present study, we sought to investigate Sox7 expression in gastric cancer (GC) and its association with the Wnt/beta-catenin signaling pathway. We also wished to determine its clinicopathological significance and prognostic implications. Sox7 expression and its effects on the Wnt/beta-catenin signaling in vitro were assessed by reverse transcription-polymerase chain reaction using the AGS, MKN-45 and GES-1 gastric cell lines. We also used immunohistochemistry on paraffin-embedded tissue samples and western blot analysis on fresh tissue samples from patients with GC. The results revealed that Sox7 expression was significantly lower in the GC samples than in distal normal tissues, which was in accordance with our results obtained from our in vitro experiments on the cell lines. However, the expression levels of beta-catenin were significantly higher. Sox7 and beta-catenin expression significantly correlated with the depth of invasion, lymph node metastasis, distant metastasis and the TNM stage. Patient samples that were Sox7-negative correlated with a significantly shorter survival time. Multivariate survival analysis revealed that Sox7 and beta-catenin had an independent effect on the survival of GC patients. Sox7 and beta-catenin expression in GC had a negative liner correlation with each other. Our findings suggest that Sox7 plays an important role in inhibiting tumorigenesis and progression, and may be a potential marker for predicting the prognosis of patients with GC.