They found several genes that were frequently methylated in the paired saliva and tissue samples including previously-implicated candidates such as p16, MGMT, DAPK, and RASSF1. Additionally, they were able to accurately detect malignant cells in saliva several months before tumor recurrence was otherwise detected in patients, indicating that saliva-based assays may be a very useful tool for effective followup of oral cancer patients. This evidence concerns the gene MGMT and lip and oral cavity carcinoma.