On Thanksgiving Day, 1981, when Diane Harper was a graduate student in engineering at the Massachusetts Institute of Technology (MIT), she phoned her dad in Kansas. "Okay, Dad," she remembers saying to him, "I'm sitting in the lab breaking these little pieces of sheet molding compound, and the only person in the world who cares is my advisor, who wants the work done, and you, because you're my dad. I can't do this anymore," she told him. "This isn't where my heart is."

Her heart, not to mention her dad's, was still with her mother, who had died in July of that year from aggressive breast cancer. Harper had watched the person she admired most be "torn apart," she says, by fragmented medical care. "It was very much body-part care" that her mother received, she recalls. "'I did the surgery so I'll take the stitches out.' 'You have to go to PT for your arm. Don't talk to me about that.' 'Oh, you're depressed; well, go find a psychologist.' . . . [My mom] really felt like she wasn't a person," Harper remembers, like "nobody was listening to her anymore."

One day, when the nurses, residents, and doctors had left the hospital room, Harper looked at her mother and said, "I can do a better job than that, Mom. I know I can."

"Yeah, you can," her mom agreed, "but that's not what you're trained for." Harper had an undergraduate degree in chemical engineering from MIT and was pursuing a master's in the same field. Her decision to go into engineering had no doubt been influenced by her father, an electrical and mechanical engineer whom she greatly admired. But at her mother's bedside that day, Harper suddenly felt a different calling.

It wasn't until several months later, in the lab at MIT on Thanksgiving, that she officially made the decision to change career paths. "I want to go to medical school," she told her father.

Twenty-five years later, Diane Harper is an accomplished physician- scientist at Dartmouth Medical School and an unofficial ambassador for an extraordinary advance in women's health—two brand-new vaccines that protect against 70% of cervical cancers. The vaccines target the strains of human papillomavirus (HPV) that cause most cervical cancers, abnormal Pap smear results, and genital warts, plus a number of other cancers and additional diseases besides.

Although cervical cancer is no longer a major killer in the U.S., more than 250,000 women die from it each year worldwide, according to the World Health Organization. The decline in the disease in the U.S. is due to the widespread use of Pap smears, which detect abnormal cells in the cervix so they can be treated before they turn into cancer. But in developing countries, women don't have access to Pap smears or to effective treatment. So while the HPV vaccines' primary benefit in the United States will be to reduce abnormal Pap results, worldwide the vaccines could save hundreds of thousands of lives.

Harper was a principal investigator for clinical vaccine trials for both Merck and GlaxoSmithKline—each of which has developed an HPV vaccine. She first became involved with the trials in the early 1990s because she had been developing self-collection methods for HPV and Pap smears. Having a method for women to collect cervical samples themselves would be an important

component of the trials, so both companies sought her expertise. Her long-term involvement with the studies—and the fact that neither company paid her—have made her a credible spokesperson on the subject. Last year, she traveled almost non-stop, to more than 60 countries, to educate health-care workers and policy-makers about HPV and the new vaccines.

"I'm one of the very few people who can give a balanced talk because I've been in both trials," says Harper. She discusses each vaccine as a scientific, public-health advance rather than as "a product from a particular company," she explains. "I think that's a real advantage. . . . It allows you to bring out multiple ideas."

In August 2006, she helped teach a course in Bangkok, Thailand—to around 70 health officials from around the world—on HPV, the vaccines, and cervical cancer. In fact, Harper is spending the entire 2006-07 academic year on sabbatical, advising the World