Decreased expression of BATF2 is significantly associated with poor prognosis in oral tongue squamous cell carcinoma

BATF2, also called SARI, is associated with several cancer types, and loss of BATF2 expression is frequently detected in aggressive and metastatic cancers. The expression of BATF2 was previously shown to slow the growth rate of malignant tumor cells injected into athymic nude mice, and decreased expression of BATF2 has been correlated to poor prognosis in hepatocellular carcinoma. However, the functional role of BATF2 in oral tongue squamous cell carcinoma (OTSCC) remains unknown. In the present study, we examined BATF2 expression in 16 fresh, paired OTSCC and adjacent non-tumor tissues, as well as in a normal tongue epithelial cell line and in 5 OTSCC cell lines by quantitative PCR and western blot analysis. We also evaluated BATF2 expression in 202 paraffin‑embedded OTSCC and 30 adjacent non-tumor samples by immunohistochemistry, and its relationship with clinicopathological features and prognosis was investigated. We found that BATF2 expression was significantly reduced in the majority of the 16 OTSCC tumor tissues and the 5 OTSCC cell lines when compared with the non-tumor tissues and the normal tongue epithelial cell line, respectively. Consistent with these results, our immunohistochemistry analysis revealed that decreased BATF2 expression was present in 124 of the 202 cases and was significantly correlated with poor tumor differentiation (P=0.002). Patients with decreased BATF2 expression showed reduced survival when compared to those with high expression (P<0.001). Multivariate analysis revealed that BATF2 expression is an independent predictor of overall survival (P=0.001). These results demonstrate that BATF2 plays a tumor-suppressor role in the development of OTSCC and that BATF2 may serve as a prognostic biomarker and potential therapeutic target for this disease.