Pretreatment saliva DNA samples from 61 HNSCC patientsTumor suppressor gene promoter regions of DAPK, DCC, MINT-31, TIMP-3, p16, MGMT, and CCNA1 genesReal-time quantitative methylation-specific PCR (Q-MSP). This evidence concerns the gene CDKN2A and head and neck squamous cell carcinoma.