LAUSR

Purpose: Sex determining region Y-BOX2 (SOX2), a key regulator of the self-renewal ability of stem cells, plays a role in the initiation and development of head and neck squamous cell carcinoma (HNSCC). However, the association between SOX2 expression and the outcomes of patients with oral squamous cell carcinoma (OSCC) has not been investigated. Thus, in this study, we investigated the possibility of predicting the survival outcomes of patients with OSCC by evaluating SOX2 expression. Experiment design: First, we analyzed SOX2 expression in patients with OSCC in The Cancer Genome Atlas (TCGA) dataset by a bioinformatics approach. In addition, samples of 219 patients with OSCC from two independent Chinese centers were collected. The median follow-up time and 95% confidence interval (CI) for the cohorts were 36 (25.06, 46.93) months and SOX2 expression in these samples was determined by immunostaining using tissue microarray. The Kaplan-Meier analysis, log-rank test, and Cox proportional hazards regression model were used to determine univariate and multivariate analyses, and hazard ratios for overall survival (OS), respectively. Results: In TCGA database, amplification of SOX2 was negatively correlated with the OS rate for patients who survived more than 300 days after the first diagnosis. Moreover, 39.7% of the samples from the cohorts showed high SOX2 expression. We found a significant difference in the survival rate between patients with high and low SOX2 expression ranging from 13 to 126 months. Conclusion: High SOX2 expression can predict poor long-term, but not short-term, survival outcomes in patients with OSCC. Our findings not only indicated that SOX2 may be a novel biomarker for the long-term prognosis of OSCC but also strongly supported the cancer stem cell theory that dysregulation of the self-renewal ability of stem cells may contribute to the development of OSCC. Citation Format: Xuefeng Zhang, Hao Xu, Chongkui Sun, Xinhua Liang, Peng Deng, Xin Zeng, Qianming Chen. SOX2 is a novel biomarker for poor long-term outcomes in oral cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3059.