DNA hypermethylation of CADM1, PAX5, WT1, RARβ, and PAX6 genes in oropharyngeal cancer associated with human papillomavirus

Recently, an increasing incidence of HPV-induced oropharyngeal squamous cell carcinoma (OPSCC) has been observed. Moreover, locoregionally advanced stages require a combined modal approach, and the prognosis is poor. Therefore, it is essential to find early diagnostic and prognostic biomarkers. DNA methylation changes play a crucial role in the process of carcinogenesis and are often investigated as promising biomarkers in many types of cancer. For analysis of DNA methylation levels of selected tumour suppressor genes in HPV-positive and HPV-negative samples (including primary tumours and corresponding metastases of metastasizing OPSCCs, primary tumours of non-metastasizing OPSCCs, and control samples), methylation-specific MLPA and methylation-specific high-resolution melting analyses were used. A significant difference in methylation between OPSCCs and the control group was observed in WT1, PAX6 (P