Background: p16 is a FDA approved surrogate biomarker for predicting human papillomavirus (HPV) associated oropharyngeal squamous cell carcinoma (OPSCC) with high sensitivity and moderate specificity. A p16 positive HPV negative phenotype indeed exists. Increased nuclear β-catenin expression has also been shown to correlate with HPV status in OPSCC. We, therefore, tested a novel model by combining β-catenin with p16 to increase the specificity for HPV prediction in OPSCC. Methods: Expression levels of β-catenin (nuclear and membrane immune-reactivity) and p16 were evaluated by immunohistochemistry (IHC) staining in 101 OPSCC tissues. HPV status was determined by HPV DNA in situ hybridization. Logistic regression models were used to estimate single or multiple biomarkers in HPV prediction. The prediction power, sensitivity, and specificity were determined by the Receiver Operating Characteristic (ROC) analysis. Results: All three biomarkers (p16, nuclear and membrane β-catenin) were significantly associated with HPV status (P < 0.01 for all). p16 alone showed the highest predictive power with area under the curve (AUC) of 0.9074 compared to 0.6762 for nuclear β-catenin and 0.7635 for membrane β-catenin. Multivariable analysis indicated that the odds ratios and 95% confidence interval (CI) for HPV positivity were 381.21 (17.14-8476.34), 4.93 (0.78-31.02), and 0.98 (0.97-1.00) for p16 (P < 0.001), nuclear β-catenin (P = 0.089) and membrane β-catenin (P = 0.085), respectively. The three-biomarker model had a sensitivity (99%) close to p16 alone (100%), but a higher specificity (89%) than p16 alone (81%) and showed prognosis value for overall survival (P = 0.0002) and disease-free survival (P = 0.0158). The model adjusting of clinical covariates only (AUC = 0.794) or adjusting of both clinical covariates and the three biomarkers (AUC = 0.852) did not produce a better HPV prediction as compared to the three-biomarker model (AUC = 0.962). Conclusion: Our findings suggests that the novel strategy of combining β-catenin with p16 increases the specificity for HPV prediction in OPSCC compared to p16 alone and deserves further validation in different clinical settings. (This study was supported by grants from Small Business Innovation Research (SBIR) Program (HHSN261201200097C) and National Institutes of Health (R33 CA161873) and Georgia Cancer Collation Distinguished Scholar Award to Dr. Zhuo Georgia Chen.)

Citation Format: Guoqing Qian, Hong Xu, Zhongliang Hu, Sungjin Kim, Dongsheng Wang, Hongzheng Zhang, Zhengjia Chen, Susan Muller, Nabil Saba, Dong M. Shin, Andrew Wang, Zhuo Georgia Chen. Enhancing specificity in predication of human papillomavirus associated oropharyngeal squamous cell carcinoma by combining biomarkers p16 and β-catenin. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1852. doi:10.1158/1538-7445.AM2014-1852