I’m the son of two physician-scientists. My parents have told me that I always said I wanted to be a doctor. I grew up in Finland, but when I was 11 or 12, we lived in New Jersey for a while. My parents did postdoctoral fellowships at the University of Pennsylvania. That’s the first time I remember going into a lab.
In my first year of medical school at the University of Helsinki, I decided I wanted to be a surgeon. It seemed very concrete to me, to be someone who fixes things with their hands. I knew that surgical programs were competitive, and I thought it would help me get into one if I also had a PhD.
I ended up working in the lab of Kari Alitalo, who is a leader in the study of factors that control the growth of blood and lymphatic vessels. Because Kari was famous internationally, scientists from all over the world rotated through his lab. Even though we were working in this small country in Northern Europe, I felt very connected to the wider scientific community.
Divided Attention Between Research and Patient Care
During this time, I was going to classes and training to be an MD during the day, but at night I was spending as much time in the lab as I could. I even took a year off from medical school to finish some research papers I was working on.
When I defended my PhD in 2008, I still wasn’t sure what I wanted to do. Working with patients and getting to know them personally was very rewarding. But at the same time, I thought that working in the lab and making great discoveries would give me the opportunity to help many more people, instead of helping them one at a time. I decided the best way to bridge that gap was to go into cancer research.
Learning to Be an Independent Scientist
I had a lot of friends who were doing postdocs in the United States, most of them in Boston. I started looking into the best cancer labs there. One name that kept coming up was Tyler Jacks and his lab at the Massachusetts Institute of Technology (MIT).
Tyler is a leader in developing genetically engineered mouse models of cancer. When I was doing research on whether to apply to his lab, I learned that he’s also a great mentor with an astounding training record. Just about everyone who’s worked at his lab has gone on to be a leader in their field. I felt very fortunate to be accepted into his lab.
One quality that makes him such a good mentor is that he lets you take complete charge of your science. He gives a lot of feedback and guidance, but he also teaches you to be independent. We even got to interview and train our own technicians. I came out of his lab with an incredible level of experience. I don’t know if I would be where I am today if I hadn’t gone through there.
It was also a very lucky time to be working at MIT because two important technological advances were happening within the same institution. One was CRISPR gene editing, and the other was single-cell RNA sequencing. I was able to be one of the first people to use both in cancer research. Through this experience I also met some great collaborators who helped advance my research.
Finding a Research Focus
While I was at MIT, I studied a signaling pathway called WNT in lung adenocarcinoma. People who have more-advanced disease tend to have high levels of WNT signaling within their tumors.
I used a mouse model that had been established in Tyler’s lab to study the cells that have this signaling. I found that there’s one type of cell within a tumor that drives the characteristics related to increased malignancy and tumor propagation — the aspects that make cancers difficult to treat. The discovery that a subset of cells could affect a tumor’s overall aggressiveness got me interested in the study of heterogeneity in cancer. Heterogeneity is the focus of my lab today.
Harnessing Technology for New Treatment Approaches
Before the development of single-cell RNA sequencing, it would not have been possible to study heterogeneity the way we study it today. You either had to study the whole tumor in bulk or you biased yourself by focusing on certain markers on subpopulations of cells. Single-cell technology allows you to look at an entire tumor cell by cell.
Tumors are so complex and diverse that it’s probably fair to say there are no two cells within a tumor that are exactly alike. The complexity is daunting. But with the right tools, we can learn to make sense of it. And once we understand it, we can manipulate it.
One of the goals of my research is to develop drugs and other methods that make tumors less heterogeneous. We want to push the cells into a state in which treatments we already have will work against them — whether that’s chemotherapy, targeted drugs, or immunotherapy. By gaining therapeutic control over these different cell types, I believe that we can really have an impact on the treatment of cancer in the future.