Jason Mendelsohn had been married for close to 20 years and was happily raising three kids when he noticed the painless lump on his neck while shaving three years ago. Within days, he had been diagnosed with a deadly form of cancer caused by a virus that he probably caught while in college, decades before. Mendelsohn, now 48, is the classic victim of head and neck cancer caused by HPV, the human papillomavirus. A new study out this week shows there’s a silent epidemic of HPV-related cancers among men. A team at the University of Florida, Baylor College of Medicine and elsewhere found that 11.5 percent of U.S. men were actively infected with oral HPV between 2011 and 2014, and 3 percent of women were. That adds up to 11 million men and 3 million women, the researchers report in the Annals of Internal Medicine. It’s a sexually transmitted infection and the more sex partners someone had, the bigger their risk. But the study found smoking also increased the danger of a high-risk infection, and, perhaps surprising to some, that men and women alike who smoked marijuana were far more likely to develop a cancer-causing strain of HPV. Jason Mendelsohn of Orlando was diagnosed with HPV-related oral cancer. He'd been married for 21 years and had three kids and may have been infected with the virus when he was in college. Studio T Photography “The predicted probability of high-risk oral HPV infection was greatest among black participants, those who smoked more than 20 cigarettes daily, current marijuana users, and those who reported 16 or more lifetime vaginal or oral sex partners,” the researchers wrote. Most people get over these infections and never even know they had them. HPV doesn’t cause any symptoms at first. But in some people, it stays in the infected tissues and causes DNA damage that, years later, causes a tumor to grow. Rising rates of oral cancer HPV is the single biggest cause of cervical cancer and certain types of head and neck cancers called oropharyngeal cancers, according to the Centers for Disease Control and Prevention. Between 2008 and 2012, close to 39,000 people were diagnosed with a cancer caused by HPV every year in the U.S., 59 percent of them