Evaluation of Vimentin as a Potential Poor Prognostic Indicator and Salivary Biomarker for Oral Cancers and Pre-Cancers by Mass Spectrometry Based Proteomics

Abstract

Abstract Background : Oral tongue squamous cell carcinoma (OTSCC) is an aggressive cancer with high morbidity and mortality rates, despite multimodality management. There are currently no clinically relevant molecular markers to help identify patients at a higher risk of recurrence and failure. Methods: 2D-DIGE coupled with tandem mass spectrometry was performed on tissues obtained from early staged OTSCC along with its paired apparently adjacent normal tissue samples (n=10). Top upregulated protein was validated using another independent set of tissue samples by Immunohistochemistry (n=346), comprising of retrospective early stage OTSCC (n=150) and prospective series of oral pre-cancers, normal and oral cancers (n=195). For further validation of protein expression, saliva samples collected from Oral Cancer and pre-cancer samples were analysed by ELISA (n=80). Results: We found vimentin, the mesenchymal protein to be the most upregulated protein in tongue tumour tissues compared to adjacent apparent normal tissues. Vimentin was found to be significantly overexpressed in oral pre-cancers along with cancers compared to normal tissues. Conclusion: Vimentin detection in saliva can be useful diagnostic test to detect oral precancers that may have malignant potential needing closer follow up. Salivary ELISA for vimentin can additionally be useful for disease monitoring in oral cancers.