Oct. 9 (HealthDay News) -- Human papillomavirus (HPV) appears to be linked to an increase in cases of a rare type of head and neck cancer, a new study has found.

Nasopharyngeal cancer -- a tumor that grows behind the nose and at the top of the throat, above the tonsils -- affects about one of every 100,000 people in the United States. According to the researchers, this is the first time that a connection has been made between HPV and nasopharyngeal cancer.

"We are in the middle of a tonsil cancer epidemic, seeing many patients with tonsil cancer linked to HPV," study author Dr. Carol Bradford, a professor and chairwoman of otolaryngology at the University of Michigan Medical School, said in a university news release. "It turns out that HPV may also be a new cause of this rare form of cancer that occurs in this hidden location."

Bradford and her colleagues analyzed tissue samples from five patients with nasopharyngeal cancer and found HPV in four of them. The four HPV-positive tumor samples were negative for Epstein-Barr virus, previously recognized as one of the major infectious causes of nasopharyngeal cancer.

The study was published online Sept. 15 in Head & Neck.

"Since I began studying head and neck cancer, I have wondered what the cause of Epstein-Barr-virus-negative nasopharyngeal tumors might be," Thomas Carey, a professor of otolaryngology and pharmacology, co-director of the head and neck oncology program at the university's Comprehensive Cancer Center and another author of the study, said in the news release. "This research suggests that there is a changing etiology for nasopharyngeal cancer in the North American population that may mirror the HPV-positive epidemic of tonsil cancer."

The researchers said that a larger study needs to be conducted to clarify the role of HPV in nasopharyngeal cancer.

SOURCE: University of Michigan, news release, Oct. 9, 2009