Most of the other proto-oncogenes like NOTCH1, FGFR1, EGFR, CCND1 or tumor suppressors like CDKN2A, ARID2 and MLH1, a mismatch repair gene, that are known to be frequently mutated in oral or head and neck squamous cell carcinomas in general were seen to have less than or equal to 20% mutation frequency. This evidence concerns the gene CDKN2A and head and neck squamous cell carcinoma.