TIMP3 and head and neck squamous cell carcinoma: We test the hypothesis that the surveillance of DNA methylation in five tumour-suppressor genes (RASSF1α, p16INK4a, TIMP3, PCQAP/MED15) will allow us to diagnose HNSCC patients from a normal healthy control group as well as to discriminate between Human Papillomavirus (HPV)-positive and HPV-negative patients.