Human papillomavirus, or HPV, the leading cause of cervical cancer in women, is also a major cause of oral cancer in men, according to a new study in the United States reported by media Saturday.

The sexually transmitted virus causing cancers of the mouth and upper throat is probably the result of an increase in oral sex and the decline in smoking, the study said.

The new study looked at more than 30 years of National Cancer Institute data on oral cancers. Researchers categorized about 46,000 cases, using a formula to divide them into those caused by HPV and those not connected to the virus.

They concluded the incidence rates for HPV-related oral cancers rose steadily in men from 1973 to 2004, becoming about as common as those from tobacco and alcohol.

However, the only available vaccine against HPV, made by Merck & Co. Inc., is currently given only to girls and young women.

Now Merck plans this year to ask government permission to offer the shot to boys.

In related research, Penn State University scientists reported that cigarette smoke may aggravate HPV and raise the risk of cervical cancer.

The HPV is the fastest growing sexually transmitted disease in the nation. Cervical cancer is a leading cause of cancer-related death in women in developing countries.

According to the American Cancer Society, it was estimated that 11,150 new cases and 3,670 deaths would be reported in the U.S. from cervical cancer in 2007.

(Agencies via Xinhua February 2, 2008)