Of p16 positive OPSCC patients, 42% had a regular smoking history and 20% did abuse alcohol at diagnosis, however, these numbers for p16 negative OPSCC and other HNSCC patients were 73%, 41%, and 66%, 44%, respectively (p < 0.001 for both tobacco and alcohol abuse, Chi-squares are 72.561 and 20.567). Here, CDKN2A is linked to head and neck squamous cell carcinoma.