The low KRAS mutation frequency in the present study is in agreement with previous small-scale studies of HNSCC that reported a mutation frequency of 2.4% (1/42 samples) in oral squamous cell carcinoma [10], 4.5% (1/22 samples) in oropharyngeal cancer [33] and 0% (0/16 samples) in HNSCC [9]. Here, KRAS is linked to oropharynx cancer.