Epigenetic Biomarkers in the Saliva for the Diagnosis of Squamous Cells Carcinoma of the Oral Cavity

Head and neck squamous cell carcinoma (HNSCC) are malignant tumors originating from the epithelial mucosa of the upper aerodigestive tract. The oral cavity is the most frequent location of HNSCC (oral squamous cell carcinoma: OSCC). Tobacco use and alcohol consumption are the greatest risk factors. The Hauts de France region has one of the highest incidence rates of OSCC. The overall survival of patients with OSCC remains low, with a 5-year overall survival rate of around 60%. In addition to the oncological prognosis, OSCCs and their treatment have a significant impact on the quality of life of patients. An early diagnosis of OSCC is recommended, but it remains difficult. It can be for example challenging to diagnose OSCC in a context of oral premalignant lesions. Identifying objective biomarkers of malignancy would be an advantage and would allow better progress in the field of precision medicine and surgery for these tumors. The investigators propose to establish the diagnostic use of an optimized DNA methylation profile detected in the saliva of OSCC patients by comparing these epigenetic marks before and after tumor resection. The investigators will construct a consolidated signature of 4 genes whose DNA is subject to methylation and gene expression is restricted to cancer cells, by crossing TCGA analysis with single-cell analysis (single-cell RNA sequencing). The investigators propose to analyse DNA methylation of the corresponding genes in the saliva of n=30 OSCC patients recruited for primary surgical resection in the Department of Maxillofacial Surgery vs controls. In addition, the investigators will examine the methylation profiles before / after complete excisional surgery of OSCC. This pilot study will aim to validate the analysis of DNA methylation markers in saliva of OSCC, with the aim of improving the diagnostic precision of OSCC and, secondly, to compare these markers before and after treatment by primary surgery.