This study will made at the buccal cancer center of UNESP and involved forty patients (n = 40) and forty controls. Serum samples, oral swabs and saliva will collect at the date of diagnosis before therapy and will store at -80 ºC until analysis. Formalin-fixed paraffin-embedded oral squamous cell carcinoma tissues and other biologic samples will process with phenol/chloroform extraction method.