Immunohistochemical and Molecular Analysis of Occludin, Phosphatidylinositol-4,5-Bisphosphate 3-Kinase Catalytic Subunit Beta Isoform and Scribble Planar Cell Polarity Protein in Oral Squamous Cell Carcinoma Progression: A Three-Marker Exploratory Study

Oral squamous cell carcinoma (OSCC) remains a significant global health concern due to its poor prognosis and late-stage diagnosis. Identifying reliable molecular markers may improve prognostication and therapeutic decision-making. In this study, the expression of Occludin (OCLN), PIK3CB and SCRIB were evaluated in OSCC. A total of 84 formalin-fixed paraffin-embedded samples were examined. Immunohistochemistry was performed to assess protein expression and quantitative real-time PCR was used for analysis. Expression levels of all three markers showed a progressive increase from well-differentiated to poorly differentiated OSCC, with statistically significant correlations to tumour grade. Both protein and mRNA analyses confirmed upregulation of OCLN, PIK3CB and SCRIB in poorly differentiated tumours. These findings suggest that overexpression of these markers may reflect tumour aggressiveness and the clinical applicability of these biomarkers in therapeutic stratification requires further validation in large prospective and functional studies, which should be interpreted cautiously.