Overexpression of BST2 Is Associated With Nodal Metastasis and Poorer Prognosis in Oral Cavity Cancer

Objectives/Hypothesis: Bone marrow stromal cell antigen 2 (BST2) was one of the proteins that were found to be related to tumor metastasis in our previous proteomic study. Now we examine its clinical role on the oral cavity squamous cell carcinoma (OSCC). Study Design: Individual retrospective cohort study and basic research. Methods: Immunohistochemical analysis, Western blotting, and quantitative real-time polymerase chain reaction were used to demonstrate the expression levels of BST2 on 159 OSCC tumors. RNA interference was utilized for cell migration and proliferation study in vitro. Results: BST2 expression was significantly higher in OSCC cells of metastatic lymph nodes and primary tumor cells, compared to adjacent normal epithelia. Higher BST2 expression was associated with positive N stage, advanced overall stage, perineural invasion, and tumor depth (P=.049, .015, .021, and .010, respectively). OSCC patients with higher BST2 expression had poorer prognosis for disease-specific and disease-free survival (P=.009 and .001, respectively). Multivariate analyses also demonstrated that higher BST2 expression is an independent prognostic factor of disease-specific and disease-free survival (P=.047 and .013, respectively). In vitro suppression of BST2 expression in OEC-M1 cells showed that BST2 contributes to tumor migration of OSCC cells. Conclusions: The findings in this study indicate that BST2 expression in OSCC tumors is an independent prognostic factor of patient survival and associated with tumor metastasis.