Portrait of a leader in immunotherapeutics

It's the question that every grade school kid has to answer at some point or another--"What do you want to be when you grow up?" My mom still has the second grade paper on which I first wrote down that I wanted to be a "physician scientist." I'm quite certain that I probably didn't know exactly what a physician scientist was at the time. I certainly didn't know any physician scientists personally, nor was I exposed to academic environments in the tiny Minnesota town in which I grew up. All I'm certain of, was at that time, I liked reading about science. Unfortunately, I soon came to know the medical profession all too personally.