Expression of cornulin in oral premalignant lesions.

The aim of this study was to evaluate expression of cornulin in oral mucosa as an adjunct to histopathologic grading of oral epithelial dysplasia (OED). Biomarker expression was assessed in normal oral mucosa, low-grade OED (LD), high-grade OED (HD), and oral squamous cell carcinoma (OSCC) by using immunohistochemistry. Photomicrographs were evaluated with Aperio Imagescope using a positive-pixel-counting algorithm. A histo-score (H-score) was calculated on the basis of staining intensity and the percentage of positive cells (%-staining). Intrarater reliability for H-score and %-staining was determined by calculating interclass correlation coefficients. Mean differences in H-scores and %-percent staining values were each analyzed by using an analysis of variance and Tukey's post hoc procedure. Cornulin expression progressively diminished with increasing grades of dysplasia and OSCC. Interclass correlation coefficients for H-score and %-staining were each greater than 0.99. Except for OSCC versus HD, all other pairwise comparisons were statistically significant (P < .0001) for H-score and %-staining. Cornulin expression helped differentiate between low-grade and high-grade oral epithelial dysplasia, making it a potential adjunct for grading oral OEDs and a potential biomarker for risk of lesion progression. Longitudinal studies evaluating risk stratification based on cornulin expression may be warranted.