Automated Quantification of CD44, c-MET, EGFR, MTOR, and GLUT1 Expression in Head and Neck Squamous Cell Carcinoma: The Impact of p16 Status and Response to Chemoradiation

Abstract

This study assessed automated quantification of CD44, c-MET, MTOR, EGFR, and GLUT1 protein expression in a tissue microarray of 109 Stage II-IV p16 positive and negative head and neck squamous cell carcinomas (HNSCC) treated with definitive chemoradiation. Immunohistochemistry-based protein expression was quantified in an automated manner using digitally scanned images processed with Definiens Tissue Studio software to generate a histologic score (H-score, range 0-300) which was normalized for each biomarker. Biomarker expression levels were correlated with one another and with p16 status. Effects of biomarker and p16 status on locoregional control, disease-free survival, and overall survival were analyzed using Kaplan Meier and Cox proportional hazard modelling. There was a significant negative correlation between CD44 and p16 expression and significant positive correlations between CD44 and MTOR, CD44 and GLUT1, c-MET and MTOR, and MTOR and GLUT1. When patients were stratified by p16 status, the significant positive correlation between CD44 expression and MTOR remained for both the p16 positive and negative subsets, while correlations between CD44 and GLUT1 and c-MET and MTOR were seen in the p16 negative subset only. A significant correlation between MTOR and GLUT was seen overall and for the p16 positive subset. When the effects of biomarker expression on clinical endpoints were examined, histologic scores below the defined cut-points for CD44 and c-MET were each associated with improved locoregional control. Higher expressions of CD44, c-MET, EGFR, and GLUT1 were associated with inferior disease-free and overall survival. On multivariable analysis, p16 positivity remained independently associated with improved locoregional control, disease-free survival, and overall survival, high CD44 remained independently associated with inferior locoregional control, disease-free survival, and overall survival, and EGFR with inferior disease-free and overall survival. In conclusion, the use of an automated system to quantify IHC expression allowed objective correlation between biomarkers and stratification of patients, revealing that higher expressions of CD44, c-MET, EGFR, and GLUT1 were associated with poorer disease-free and overall survival.