Slug overexpression and association with clinicopathological features in gastric cancer.

Abstract

426 Background: Slug is a suppressive transcriptional factor of E-cadherin, acting as an activator of epithelial-mesenchymal transition(EMT). Its clinical relevance in gastric cancer(GC) is not fully known. Methods: Our study evaluated the expression patterns of EMT and cancer stem cell markers in GC patients who had clinical stage 2-3, underwent gastrectomy, D2 lymph node dissection (LND), adjuvant chemotherapy. Immunohistochemistry of E-cadherin, vimentin, CD133, ABCG2, NEDD9, SMAD4, XB130, Slug, Snail were investigated from 210 gastric cancer samples using tissue microarrays. The correlation between each markers expressed and the association with clinicopathological factors were analyzed. Results: Slug expression was more frequent in stage 3 than stage 2 (p=0.000), advanced T (p=0.007) and N stage (p=0.001), while histologic type did not make difference. Slug expression correlated with the expression of cancer stem cell marker CD133 (r=0.180, p=0.015) and CD133 expression was also related with ABCG2 (r=0.412, p=0.000). High Slug group showed shorter overall survival, compared to low Slug group (median OS 134 vs 124 months, p=0.044). The 2-year and 5-year disease-free (DF) rate for patients with high Slug and low Slug was 87.1% and 79.8%, 68.1% and 79.8%, respectively(p=0.038). The DFS curve reached an earlier plateau at 11-month in low Slug group, while in high Slug group took as long as 99 months. A multivariate analysis using the Cox proportional hazards regression model demonstrated Slug to be an independent prognostic factor for overall survival; hazard ratio 0.504 [95% CI 0.278-0.916] (p=0.025). Conclusions: In stage 2-3 GC patients who underwent gastrectomy with D2 LND and adjuvant chemotherapy, high Slug expression is associated with better disease-free and overall survival. Patients may benefit by testing Slug immunohistochemistry to predict prognosis after gastrectomy.