A virus contracted through oral sex is the cause of some throat cancers, say US scientists.
HPV infection was found to be a much stronger risk factor than tobacco or alcohol use, the Johns Hopkins University study of 300 people found.
The New England Journal of Medicine study said the risk was almost nine times higher for people who reported oral sex with more than six partners.
But experts said a larger study was needed to confirm the findings.
HPV infection is the cause of the majority of cervical cancers, and 80% of sexually active women can expect to have an HPV infection at some point in their lives.
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