Mouth and throat cancer could be caused by the virus that causes genital warts and cervical cancer, and it could be spreading through sex and French-kissing, a study published Wednesday says.
"In addition to the known oral cancer risk factors - smoking, drinking alcohol and chewing betel nuts - human papillomavirus (HPV) has been added to the list," the study published in the Centers for Disease Control and Prevention's (CDC) Emerging Infectious Diseases report says.
HPV has been documented in many cases of oropharyngeal squamous cell cancer, which is on the rise, and the study suggests that the increase in these mouth and throat cancers could be caused by infection with the virus that causes genital warts and cervical cancer.
They also suggest that the rising incidence of oral cancer could be due to changing sexual behaviors.
Oral sex has become more commonplace and people have more sex partners and have sex earlier in life - all behaviors linked to HPV-related oral cancers, the study said.
Its authors, Torbjorn Ramqvist and Tina Dalianis of the Karolinska Institutet, cited earlier studies and their own research using the Swedish Cancer Registry, in writing up their findings.
"In a recent study... it was shown that the risk of developing oral HPV infection increased with increases in lifetime oral or vaginal sex partners," they said.
"It has also been reported that ... open-mouthed kissing was associated with the development of oral HPV infection," they said, citing the results of a study that looked at 542 US students.
"We suggest that we are encountering a slow epidemic of mainly sexually transmitted HPV-induced" oral cancers, the report said.
Oropharyngeal cancers caused by HPV are the second most common cancer linked to the virus, and their incidence is increasing.
The researchers observed that cases of throat and mouth cancer are rising in Britain, Finland, the Netherlands, Sweden and the United States, especially among young people, and more often among men than women.
The researchers urge the scientists to study the effects of the HPV vaccine available to girls and women on oropharyngeal squamous cell cancers.
If the vaccine is found effective against mouth and throat cancer tumors, health officials should consider expanding the universe of patients vaccinated against HPV infection to include boys and men, they said.