Biological Role of Synuclein-γ (SNCG) and Ki 67 in Oral Potentially Malignant Disorders and Squamous Cell Carcinomas of Buccal Mucosa: An Immunohistochemical Study

Background Oral squamous cell carcinoma (OSCC) is a subset of head and neck squamous cell carcinoma and constitutes about 94% of all oral malignant tumors. Despite advances in therapies, the overall 5-year survival rate has remained unchanged during the past decades, mainly due to delayed diagnosis, underdiagnosis or misdiagnosis. Hence, the data demonstrate the importance of early diagnosis and indirectly show that identifying diagnostic biomarkers is extremely urgent. Our study aims to determine Synuclein-γ and Ki 67 as potential biomarker for the diagnosis of OSCC. Identification of changes in this protein may be useful for promoting the early detection and early treatment of oral squamous cell carcinoma. Material and Methods The study was approved by the institutional ethics committee (IEC2: 67/2022). The material for the study comprised of archival formalin fixed paraffin embedded tumor blocks (FFPE) of oral potentially malignant disorders (n=40) and primary oral squamous cell carcinomas (n=40) cases. Sections were cut and immunohistochemically stained with Anti-SNCG Mouse monoclonal antibody [1H10D2] (STJ98409) and Ki-67 Mouse monoclonal antibody (prediluted/ready to use) [Clone: MIB1]. Statistical analysis was carried out using SPSS software and Chi square tests were used to determine the associations. A p value of < 0.05 was considered to be significant. Results In the study group for OPMDs, positive SNCG expression in the cytoplasm of the dysplastic cells was observed in 37/40 (92.5%) cases. Whereas positive Ki 67 expression in nucleus of the dysplastic cells was observed in 34/40 (85%) cases. In the study group for OSCC, positive SNCG expression in the cytoplasm of the tumor cells was observed in 38/40 (95%) cases. Whereas positive Ki 67 expression in nucleus of the tumor cells was observed in 39/40 (97.5%) cases. There was significant correlation between expression of SNCG with habits (p=0.005), lymphovascular invasion (p=0.037), margin clearance (p=0.039) and patient outcome (p=0.021). Also, there were significant correlation between the expression of Ki 67 with gender (p=0.004), histological grade of tumor (0.014) and stage of nodal status (p=0.026) Conclusion While Ki 67 as a standalone biomarker suffices in prognosticating both OSCC and dysplasia, there is a lack in significant correlations when it comes to certain parameters in which expression of SNCG was shown to be helpful in the present study. This complementary expression dynamic between Ki 67 and SNCG makes a strong case for using both these biomarkers, probably as a panel in the prognostication of dysplasia and OSCC. However further studies on a larger sample size and better patient follow –up data are needed for a better understanding of the molecular characteristic of the tumor cells which can be useful in developing effective treatment strategies.