A study of 300 patients who either had throat cancer or did not have the disease showed that those who were infected human papilloma virus (HPV) had a 32 fold greater chance of developing oral cancer than the uninfected group. Various risk factors of oral cancer have been identified and these include smoking and excessive alcohol consumption as well as HPV infection. In patients who do not smoke or consume excessive amounts of alcohol, oral cancer has been increasing and this appears to be due to HPV infection.

In 2009, an association between oro-pharyngeal cancer and HPV16 (one of the HPV types that is strongly associated with cervical cancer) was shown. As might be expected, oral sexual contact, including oral-oral (open mouth kissing) and oral-to-genital contact, may play a role in human-to-human transmission of HPV infection.

It remains to be seen whether the quadrivalent HPV vaccine (Gardasil) will be as effective against oral cancer as it is against cervical cancer.