For head and neck cancer, saliva and oral rinse have been used to obtain DNA from the oral epithelium to analyze the DNA hypermethylation profile [101,108] Among potential biomarkers for oral carcinogenesis, HOXA9 (Homeobox A9) and NID2 (Nidogen 2) hold high promise due to their apparent sensitivity and specificity. The gene discussed is HOXA9; the disease is head and neck cancer.