Immunohistochemical expression of P16 and HER2/neu in normal oral mucosa, oral epithelial dysplasia, and oral squamous cell carcinoma


Background: Oncogenesis in the oral cavity is widely believed to result from cumulative genetic alterations thatcause a transformation of the mucosa from normal to dysplastic to invasive carcinoma. The p16 gene produces p16protein, which in turn inhibits phosphorylation of retinoblastoma (Rb), p16 play a significant role in earlycarcinogenesis. A number of epidermal growth factor receptor (EGFR) family, HER2/neu, has received muchattention because of its therapeutic implications. The aims of the study were to evaluate and compare theimmunohistochemical expression of the cell cycle protein P16 INK4a and c-erbB2 (HER2/neu) in NOM, OED, andOSCC. Correlate both marker expression with each other as well as with various clinicopathological findings.Materials and methods: Sixty two formalin-fixed, paraffin embedded tissue blocks (20 cases of normal oral mucosa,17 cases of oral epithelial dysplasia, and 25 cases of oral squamous cell carcinoma) were included in this study, animmunohistochemical staining was performed using anti p16 monoclonal antibody, and anti HER2/neu polyclonalantibody.Results: Positive IHC expression of p16 was found in 18 cases (90%) of NOM, 16 cases (94.1%) of OED and in 20 cases(80%) of OSCC. Positive IHC expression of HER2/neu was almost undetectable in NOM, while it was found in 9 cases(52.9%) of OED, and in 15 cases (60%) of OSCC.The correlation between the expression of both markers werestatistically highly significant in NOM, significant in OED, and non significant in OSCC.Conclusions: This study signify the important role of p16 and HER2/neu in oral carcinogenesis and in the evolution ofthe mucosa from normal to dysplastic to invasive carcinoma


NOM, OED, OSCC, P16, HER2/neu