Medical ignorance all too often meant that as a physician I was helpless in too many circumstances."

The treatment of diabetes—the focus of his practice then—was totally different before the invention of blood glucose meters and insulin pumps, before today's many varieties of insulin and other new medications. The mystery of diabetes had supposedly been solved in the 1920s, when a team of Canadian scientists discovered insulin and used it to treat a 14-year-old boy who had been a "hopeless invalid," according to the Nobel Prize announcement for 1923. Yet insulin was a treatment, not a cure, "and that boy died at age 33 of coronary artery disease," Korc says. "The doctors then didn't know what side effects to look for."

Learning about the link between diabetes and another disease, pancreatic cancer, launched Korc in 1984 on the trajectory that has defined his career. A conscientious reader of the medical literature, he used to spend hours in the library. (Now, thanks to the internet, he can read relevant journal articles well before their official publication date.) Japanese researchers had found that patients with type 2 diabetes mellitus were at greater risk of developing pancreatic cancer. "Eureka!" Korc wrote in his 2006 essay. "As an endocrinologist with an interest in diabetes who had trained in laboratories that studied pancreatic physiology and pancreatic gene regulation, and who was yearning to do translational research, I suddenly discovered my calling." He would investigate the role of growth factors in pancreatic cancer—something no one had yet looked at. And what he learned might help his patients with diabetes, too.

Now, 20 years later, it is widely known that growth factors are overexpressed in pancreatic and other cancers, causing tumors to grow and metastasize. The "stop" signals for growth factor production are also out of order.

"I have another analogy I like to use to explain it," Korc says. "Imagine you're driving a car and the accelerator is stuck to the floor. And the brakes don't work. Not only that, the brake pedal has been converted into a second accelerator."

Korc and his 10-member research team have discovered chemicals that are able to restore the brakes in some pancreatic cancer cells; several of their ideas are

When cancer hijacks the making of hormones, the result is cacophony instead of music. The work of the doctor is to fix the piano so the music of the body can resume.

now in clinical trials. Urging his fellow endocrinologists nationwide to be more optimistic, he wrote recently that "the nihilism regarding the potential for prolonged survival of pancreatic cancer patients is no longer an option, and that is a tremendous change in perspective."

Curing pancreatic cancer is more difficult than repairing the brakes on a car—you can't put a cell up on a lift and get out your wrench. In addition, each cell's accelerator and brakes are broken in slightly different ways. "The cancer arose because the checks and balances fell apart that controlled the fidelity of what's going on inside the cell," Korc says. "Once that's gone awry, all the cells will go in a slightly different direction. Each cancer cell will be different, and each cancer will be different between different people. We're now talking about personalized therapy."

A futurist might see the solution in genomics—looking toward a day when every patient will have his or her gene profile recorded onto a microchip and inserted under the skin of the upper arm (maybe leaving a pucker like an old-fashioned vaccine). Then the doctor will be able to look at the profile and design a personalized treatment.

But Korc is not a futurist. "There are huge problems with privacy, ethics, insurance,"

he says. "Do you want to know you'll get pancreatic cancer when you're 40? Some people will refuse the microchip. Some people refuse to have a flu shot today. Or to wear a seatbelt. Or to wash their hands. All these things complement each other. Sometimes it's the simplest and most basic things that will prevent the most problems."

That first-things-first approach is evident in how Korc treats his osteoporosis patients. First, he checks for a secondary cause of the condition, such as an overactive thyroid or a calcium leak. Then he starts a program of education and motivation.

"Bone is a living tissue," he tells them. "There's a constant balance between bonebuilding and bone-chewing. Bone constantly goes through stresses." Although most people start losing bone after age 30, there are many things you can do to keep your bones strong or to protect bones that have already become fragile, Korc says. "Throw away the cigarettes. Start exercising. Take vitamin D if you're deficient. Eliminate slippery surfaces in your house. Do you have a tendency to go for walks at night? If so, bring a flashlight. Wear hip pads so if you fall—and you will eventually fall—you won't break a hip."

Why does Korc try to do everything—motivating patients, researching growth hormones, managing the huge Department of Medicine, and training new doctors? "There's a great sense of fulfillment," he wrote in his 2006 essay, from seeing a patient get better. But when he thought about giving up research at one point, he decided that "the joy of scientific discovery had become too seductive. I found that I simply could not help myself, and that I absolutely had to write manuscripts and give presentations at national meetings because it was fun and exciting."

Training the next generation of physicians provides a different sort of satisfaction. "One of my favorite parts of the day is the Morning Report," Korc says, referring to an hour in which residents get together to discuss puzzling cases. Watching from the audience, Korc says, "is always a humbling experience. You have medical conditions that present in such unusual ways. You learn from the process—but you also realize you can't know everything. Nobody can."