The antioncogenic effect of Beclin-1 and FOXP3 is associated with SKP2 expression in gastric adenocarcinoma

An overexpression of S-phase kinase-associated protein 2 (SKP2) is frequently observed in human cancer progression and metastasis, and evidence suggests that SKP2 plays a proto-oncogenic role both in vitro and in vivo. However, the function of SKP2 in gastric adenocarcinoma remains largely obscure. We investigated SKP2 expression in human gastric carcinomas. Tissue samples were acquired from 182 cases of gastric adenocarcinoma that were surgically resected from 2006 to 2012. Immunohistochemical staining for SKP2, Beclin-1, and forkhead box protein P3 (FOXP3) was performed. Pearson chi-square test was used to evaluate the associations among clinicopathological variables. The Kaplan–Meier method, the log-rank test, and the Cox proportional-hazards model were used in the analysis of the overall survival (OS) and disease-free survival (DFS). As a result, SKP2 overexpression in gastric adenocarcinomas showed a significant correlation with several favorable clinical factors, including the tumor size, T category, N category, lymphatic invasion, vascular invasion, OS, and DFS. SKP2 expression was positively correlated with the tumoral FOXP3, Beclin-1 expression, and regulatory T cell (Treg) infiltration. The difference in DFS between the SKP2 positive and negative group was attenuated by FOXP3 high expression, Beclin-1 high expression, and Tregs infiltration. Attenuation of the difference in OS by FOXP3 high expression, Beclin-1 high expression, and Tregs infiltration was not significant. In multivariable analysis, SKP2 expression was not correlated with OS and DFS. Our study showed a complex interrelationship between SKP2 and Beclin-1 and FOXP3 expression in gastric adenocarcinoma. The antioncogenic effect of Beclin-1 and FOXP3 expression in gastric adenocarcinoma is related to SKP2 expression.