オーラルセックス
Some experts estimate that while up to 50% of cancers of the tonsil may be infected with HPV, only 50% of these are likely to be caused by HPV (as opposed to the usual tobacco and alcohol causes). The role of HPV in the remaining 25–30% is not yet clear. Oral sex is not risk free and results in a significant proportion of HPV-related head and neck cancer.