Kari Jussi Hemminki is a renowned researcher who has overseen ground-breaking work at the Faculty of Medicine in Pilsen, Charles University. After many years of scientific collaboration with the Laboratory of Cancer Therapy and Tissue Regeneration at the Biomedical Centre of the Faculty of Medicine in Pilsen, he became the ERA Chair in the local Chaperon project of the Horizon 2020 challenge. In less than five years in this role, Professor Hemminki and his team published over one hundred impactful publications, 40 of which were printed in first-quartile journals.
Professor Kari Hemminki and CU's rector, Milena Králíčkova. Hemminki was recognised for his extraordinary contributions in cancer research.
Under his leadership, the Translational Cancer Genomics Laboratory he founded has received significant grant funding. This month, the researcher received an honorary degree from Charles University in a special ceremony at the Carolinum. On the occasion, he also spoke to Forum magazine.
Professor, you have had a long and dedicated career as a researcher, focusing largely on cancer research, particularly colorectal and pancreatic cancers. What was the spark that led you to pursue this area of medical research?
The inspiration came later in my career when we were dealing with DNA and the mutations caused by chemical carcinogens. From there, the focus expanded to other aspects of mutations, as cancer is one of the few diseases where such mutations are present.
Is cancer an area where excellent research is made possible or more likely because of robust funding?
It is better funded today, but that hasn’t always been the case. In the 1970s, in my native Finland, there was much greater emphasis on cardiovascular disease, as it represented the major disease burden. By comparison, cancer wasn't a big focus at that time.
And here I thought that the Nordic countries, or Scandinavia, are known for their populations inclined to outdoor and healthier lifestyles…
Yes, that was very much tied to the local diet, with the consumption of saturated fatty acids from butter and milk, which were linked to heart disease. Over time, this improved, and activity levels increased. This was a major focus during my studies and early medical career.
Research has taken you around the world: you've worked in the United States, Sweden, and Germany for many years. You’ve now been doing ground-breaking research in Czechia. What was it like working in these different countries? I know Finland and Sweden have very strong ties, so I suppose you learned Swedish in school.
Yes, we did. I began my regular work in Helsinki at the Institute of Occupational Health. Before that, I had already done postdoctoral research in the USA, with a few longer visits to both the USA and the UK. Finland is a small country, and Sweden is wealthier, so when I was offered a position at the Karolinska Institute, I accepted and stayed there for 13 years. Then, an offer came from Germany, which was very good scientifically, and I found it impossible to say no. That was at the German Cancer Research Centre (DKFZ).
And your work in Czechia?
I was preparing to retire in 2019 and could have done so in Germany, but I felt it was too early. I wanted to do more in science, and that’s how the opportunity in Czechia arose, specifically through the Chaperon project at the Faculty of Medicine in Pilsen. My department at the research centre in Germany was called Molecular Genetic Epidemiology, and in this age, you don’t change that much. So, we started similar research in Czechia, using patient collections available in Pilsen. We focused on the tumour environment, where immune cells play a critical role. It has been shown just how important they are in fighting certain cancers. Boosting the immune system has helped some types, but not others. This focus on immune cells in Pilsen was a new direction.
I’ve read, and some of my colleagues have reported in Forum, on major advances in cancer treatment over the last decade, especially in terms of personalisation and boosting the immune system…
Indeed, this immune therapy is the last major improvement in cancer treatment. It was first demonstrated about 10 years ago and has proven helpful in fighting certain cancers, like melanoma and lung cancer, though it doesn't seem to work for all types. That’s something we hope to build on and improve in the future.
One thing that students, who were doing internships in Prague regarding tumours and immunotherapy, have shared with me is that they were particularly attracted to research with real medical impact—research that can make a significant difference in patients’ lives. Even if they never meet the patients they are helping, knowing that they are improving treatment and patient outcomes is highly motivating. Do you feel the same way?
I would say yes. We have always worked with human samples. Much of earlier cancer research was based on model systems, cultured cells, or experimental animals, but our focus has always been on human cancers. What might benefit patients is what truly matters.
I was also interested in the specifics of pancreatic and colorectal cancers. I know that pancreatic cancer is particularly difficult to treat. People like Steve Jobs, Patrick Swayze, and former Czech culture minister Pavel Dostál all succumbed to the illness.
It is the deadliest cancer, and it’s difficult to treat because it is typically diagnosed after it has already metastasised. Colorectal cancer is fairly common in Czechia. Czechs aren’t the number one in this, but they’re close. Pancreatic cancer is also relatively common. On the positive side, there are screening tests for colorectal cancer for blood in stool, and if there is any suspicion, people can undergo a colonoscopy (which is recommended at regular intervals and is offered free of charge in Czechia). That’s a big advantage—it’s not the case everywhere. However, the participation rate is low, so prevention isn’t as effective as it could be.
In short, awareness should be higher—it sounds like a task for a government or ministerial campaign. Some campaigns, like those encouraging men to test for testicular cancer, have been fairly successful.
In many ways, the examination needs to be demystified. Some people are frightened to go because of what they've heard through word-of-mouth. They avoid participating, even though the reality isn’t anything like what they imagined.
Professor Hemminki (right), with fellow honorary doctorate recipient, renowned chemist M. Grätzel (a Forum interview is under preparation).
Tell me a little about the team you work with.
Well, my background has involved a lot of international collaborations. We’ve published extensively with groups from various countries and have tried to collect samples from different nations to increase the sample sizes.
The novel project we were able to set up involved obtaining a primary tumour sample from colon cancer in a patient, along with a metastasis sample from their liver. This was quite unusual—and very important for us—to obtain both samples from one patient. The liver is a major site of metastasis in colorectal cancer. Having these pairs of samples is unique in the world, and we are now nearing completion of that study. Some papers have already been published, but many others are still being finalised for publication.
For obvious reasons, it’s not easy to collect two samples from the same person separated in time. Usually, people are treated in one centre, then move on to another, making it challenging to obtain both samples from the same patient. That was an advantage we had in Pilsen.
Are there any known factors at this time explaining why colon cancer tends to spread to the liver? The liver is often referred to, in simplified terms, as the body's chemical factory, but why is there a stronger connection?
We don’t know the exact reasons yet, and it's still unclear why different cancers metastasise to different locations. Many cancers metastasise to the liver, but others spread elsewhere. It’s a mystery so far, and it’s definitely an area for further study.
Professor Hemminki congratulated by Charles University Rector Milena Králïčková on 4 March, 2025.
Is the situation dire when it reaches the liver?
It was 10 or 20 years ago, but now there are operations that can be done effectively, provided the cancer has spread to only one spot in the liver and not to multiple locations.
Do you follow up on patients' outcomes? Life expectancy, whether they fully recover, and so on?
We have information, even though we are not directly involved in clinical follow-up. However, we do track survival data, and there are people who have survived for many years.
Whether we're talking about your early years in Finland, your life in Heidelberg, Germany, or your time in Czechia, I’ve read you are an avid hiker. Do you have a favourite spot to enjoy nature?
Hiking is something we do regularly on weekends. The Heidelberg area is quite nice, but we also take hiking vacations further abroad, covering fair distances. In Czechia, I’ve hiked in the Šumava Mountains near the border, which I enjoyed very much.
What were your feelings when you found out you would be receiving an honorary doctorate from Charles University, and what are your feelings about it now?
It was an overwhelming honour to hear that. Heidelberg is somewhat like a little sister to Charles University, as both were established around the same time, and they share a rich history. It’s a real honour and another connection between these two great institutions.
| Professor Kari Jussi Hemminki |
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After studying at the University of Helsinki - where he received his Doctor of Medicine and Doctor of Philosophy degrees - Kari Jussi Hemminki completed postdoctoral studies at Johns Hopkins University in Baltimore, USA. As a professor, he worked for fifteen years at the Karolinska Institute in Sweden in the field of epidemiology. For the next fifteen years he joined the German Cancer Research Center and the University of Heidelberg. And it is from Heidelberg that Prof. Hemminki's next steps lead to the Czech Republic, specifically to Pilsen. In less than five years in this role, Prof. Hemminki and his team managed to publish over one hundred impacted publications, forty of which were printed in first-quartile journals. Under his leadership, the Translational Cancer Genomics Laboratory he founded has received a significant amount of grant funding. Professor Hemminki is an extraordinary, globally recognised and respected figure in the field of cancer genetics and epidemiology. During his professional life to date, he has produced an extraordinary number of major scientific results - his bibliographic record includes more than 1600 articles and his H-index is over 100. And he has contributed to the formulation of treatment and diagnostic procedures and classification criteria for a number of serious and fatal cancers. He is also an enterprising and stimulating leader and mentor to a number of younger researchers, some of whom have already reached the pinnacle of their own successful careers. |
