Can dual staining with p16 and Ki67 be biomarkers of epithelial dysplasia in oral lesions?

Background: Oral carcinogenesis is a multistage process with epithelial dysplasia as a premalignant condition. There is a significant inter-observer variation in diagnosing and grading the oral epithelial dysplasia. As human papillomavirus (HPV) is believed to have a strong relationship with oral carcinogenesis, using P16 as a biomarker may help in identifying the cells which may be undergoing the malignant transformation. However, due to the low specificity of P16, dual staining test P16INK4/Ki67 might be a better promising marker for identifying the transformed cells. This study was designed to evaluate the dual expression of P16 and Ki67 as a promising biomarker for dysplasia and their correlation with clinicopathological factors.Materials and Methods: Immunohistochemical analysis for p16 and ki67 was performed on 30 premalignant oral lesions and 36 oral squamous cell carcinoma (OSCC) by dual staining using the CINtec PLUS kit.Results: CINtec positivity was observed only in leukoplakia with dysplasia (46.7%) and squamous cell carcinoma (25%). None of the cases of leukoplakia without dysplasia or oral submucosal fibrosis stained positive for CINtec plus staining. In leukoplakia with dysplasia, there was no significant association with any of the clinicopathological parameters studied. In OSCC cases, alcohol intake showed statistically significant association with CINtec positivity.Conclusion: P16INK4/Ki67 assessment by dual staining is a promising biomarker for identifying dysplasia in cases with diagnostic dilemmas.