RASSF1 and oropharynx cancer: Saliva supernatant from 148 subjects: 60 healthy controls (HC), 54 oral squamous cell cancer (OSCC) and oropharyngeal cancer (OPC)The promoter methylation of p16INK4a, RASSF1A, TIMP3, and PCQAP/MED15 TSGs in salivary DNA from OSCC and OPC individualsQuantitative methylation-specific PCR (MSP-PCR) coupled with densitometry analysis