Immunohistochemical Detection of p16 (INK4a) in Leukoplakia and Oral Squamous Cell Carcinoma

Introduction: Over-expression of p16 (NK4a) has been reported in tissues of oral squamous cell carcinoma (SCC) associated with Human Papillomaviruses (HPVs). Immunohistochemical (IHC) detection of p16(INK4a) is an easy technique than molecular detection of HPVs, hence we investigated the presence of this protein in the most common pre-malignant and malignant oral lesions i. e. leukoplakia and SCC respectively. Material and Methods: We performed IHC detection of p16 (INK4a) in sections of paraffin embedded formalin fixed tissues of leukoplakia with or without dysplasia (n= 21) and SCC lesions (n= 69) and correlated with various patterns of p16 NK4a positivity with respect to histological diagnosis. I Results: In the present study, 71 % cases of oral SCC cases were positive for p16(INK4a), of which the most common pattern was diffuse nuclear and cytoplasmic staining. Among the cases with leukoplakia, 57.1% were positive for overexpression of pl6 (INK4a), wherein diffuse and sporadic pattern was observed among 23.8 percent each. Conclusion: In the present study, significant number of oral SCC cases observed overexpressing p16 (INK4a). However HPV DNA detection based studies are needed to validate the utility of IHC detection of p16 (INK4a) as a surrogate marker for HPV associated oral SCC.