When I first went to medical school, I thought I’d be a cardiologist. My dad was very sick with heart disease while I was growing up, so I spent a lot of time in the hospital. I saw how the cardiologists treated him and other patients, and I wanted to heal people in the same way.

But once I actually got to medical school, I found that I was more interested in following pathology specimens to the lab to find out what my patients...