Pioneer in the fight against cancer

It was immediately clear to Stefan Pfister and his family that they would buy this medieval farm in Ladenburg when they visited it a few years ago. Everything just fit: The walls with their historic half-timbering offer enough space for the whole family with their two children, there is a music cellar that can accommodate up to 70 listeners, and an inner courtyard for concerts and theater performances with up to 110 guests. What’s more, it only takes half an hour by bike along the Neckar River to Heidelberg, where Pfister works as a pediatric oncologist at the Hopp Children's Tumor Center (KiTZ), the German Cancer Research Center (DKFZ) and Heidelberg University Hospital.

"Our farm and the associated cultural association are a pretty extensive hobby," says Stefan Pfister, but he says it with such a glow on his face that it's clear he gains more energy from the renovation of the farm and from all the children's theater performances and weekend concerts than he puts in. It is energy that he urgently needs for his main job: Pfister is considered a pioneer in the classification and molecular diagnosis of tumors in children and adolescents; work with which he and his team are helping to increase the life expectancy of young patients with cancer.

But his scientific success is actually the result of a promise not kept. "My mother is a pediatrician," says the 48-year-old, "and my sister and I resolved that we’ll  never go to medical school, and if we do, at least we won't specialize in pediatrics." He laughs. He is not the only one to have gone back on his word: His sister has since taken over her mother's pediatric practice in Tübingen.

"I was fortunate to have come into this profession at a time when a revolution was taking place"

What first captivated Stefan Pfister during his medical studies in Hamburg and Tübingen, however, was not so much pediatrics as oncology. "I think this field offers the best opportunities to translate scientific findings into concrete applications," he says. And that's exactly what he wants: Not just to produce "beautiful research," as he puts it, but to bring about concrete improvements. That's why he also went to Harvard University as a postdoc, already focused on oncology, and deliberately scheduled for only two years "driven by curiosity to take a look at how things work in this world-famous place." Some things, he found, work better in the German health care system than in the United States, but others inspired him: He learned about the concept of Comprehensive Cancer Centers, where research and patient care take place under one roof. He saw the significant role that philanthropists play in research and medical care, the openness to collaboration with companies, the start-up culture, the pleasure researchers take in presenting and explaining their work to the public.

These are all impulses that ultimately contributed to the founding of KiTZ - the Hopp Children's Tumor Center in Heidelberg, which came into being in 2016, supported in large part by generous patrons from the region. It is one of Europe's leading facilities for treating cancer in children and adolescents. "We're talking in the region of 2,000 new cases per year in Germany," says Stefan Pfister, and because cancer in children is of a completely different nature than in adults, there is the separate field of pediatric oncology. Adults, for example, often have breast, colon and liver cancer, while children suffer primarily from brain tumors, leukemias or connective tissue tumors; all groups of diseases that, occur only rarely in adults. And cases such as glioblastomas which are a particularly malignant type of brain tumor are found in both adults and children, but the genetic mechanisms behind them are completely different in each case.

"I was lucky to come into this profession at a time when a revolution was taking place," says Stefan Pfister. Gene sequencing and the possibilities of working with petabytes of data has provided a whole new view of oncology, and Stefan Pfister and his team have played a major role in sharpening this view. His big goal is to better classify tumors. Hundreds of species exist, differing in their expression, and in the past, before modern methods, it was almost impossible to distinguish between them. His team is using the genetic and epigenetic data to make a more precise diagnosis: the scientists are therefore using sequencing to look at which genes have changed and how. They also look at how tumors develop: Many childhood cancers are caused by a single genetic change, such as the fusion of two genes that are actually located on different chromosomes. Such events can occur randomly in a cell during its developmental phase and subsequently lead to uncontrolled cell division.

 "If we know more about the cancer that each individual patient has, we can tailor treatment more precisely, meaning we have more options for action and we can reduce the side effects of therapy," says Stefan Pfister. The work of the Heidelberg team, which closely involves several disciplines such as neuropathology, has now even become the basis for the World Health Organization's tumor classification.

For him, a new phase of his career is now beginning, and perhaps the Leibniz Prize was one of the triggers for this: "For the past 20 years, we have been primarily concerned with the correct classification and diagnosis. I now want to use the next 20 years to bring better therapies to patients," he says, adding, "Even now, it's a bigger breakthrough for me when a new analytical method we've developed is covered by health insurance than when we publish another Nature paper."