Diagnostic Performance of p16ink4a in the Presence of E6/E7 mRNA in Formalin-fixed Paraffin Embedded Specimens: A Cross-sectional Study.

Introduction: Clinically significant High-risk Human Papillomavirus (HR-HPV) infection in Oral Cavity Squamous Cell Carcinoma (OCSCC) is not clearly defined. There is uncertainty regarding the true impact of HPV-related variability (ranging from 0% to 100%) when using the GP5+/GP6+/MY09/11 (L1) primer. The identification of HPV DNA in tumours is insufficient to establish a causal viral association; therefore, a gold standard test is required to determine HPV's role in malignant cells by identifying the transcripts of the E6/E7 mRNA viral oncogene and the p16ink4a biomarker. Aim: To assess the diagnostic performance of p16ink4a in the presence of E6/E7 mRNA in Formalin-fixed, Paraffin-embedded (FFPE) specimens. Materials and Methods: This cross-sectional study was conducted in the Department of Pathology at JIPMER in Puducherry, India, from February 2019 to April 2022. Combined molecular markers p16ink4a and E6/E7 mRNA (considered the gold standard) from FFPE specimens of newly diagnosed Squamous Cell Carcinoma (SCC) were analysed to identify biologically and clinically relevant Infections using Immunohistochemistry (IHC) and real-time Polymerase Chain Reaction (PCR). Results: This study indicates that tissue samples with p16 positive expression (score of 2 or higher) showed the presence of HPV E6/E7 mRNA, with a sensitivity of 100% and a specificity of 91.67%. The relationship between p16ink4a and E6/E7 mRNA expression in all OCSCC cases was found to be significant (p-value=0.003). Conclusion: The study found a significant relationship between mRNA and p16ink4a overexpression in tongue SCC. This finding suggests that alterations in mRNA expression levels are associated with changes in p16ink4a expression in tongue cancer. Such understanding could potentially aid in the development of diagnostic or therapeutic strategies targeting these molecular pathways in tongue SCC. [ABSTRACT FROM AUTHOR]