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In memoriam: Paul Kleihues


Adriano Aguzzi

Paul Kleihues, emeritus Professor of Neuropathology at the University of Zurich, passed away last week. He was a remarkable physician-scientist. When I first met him in the early 1980s, he was already among the first pathologists trying to establish methods of molecular science in the diagnostic practice of our specialty. Back in those days, DNA sequencing was still in its infancy and Paul relied on chemical determination of modified nucleotides to assess the mutagenic potential of environmental and therapeutic alkylating agents. His work of those days resulted in highly recognised publications in the top interdisciplinary journals, and forms the basis for our understanding of the tissue specificity of carcinogens. In addition to his eminent stature and contribution to the fledgling field of molecular neuropathology, Paul was an impressive innovator of his discipline. His drive and his energy led him to push and redefine all of the boundaries that he encountered. At a professional stage of seniority at which most of us enjoy a stable, quiet life, Paul always looked out for new challenges. This led him first to move from Cologne to Freiburg, where he accepted a tenured professorship of neuropathology at the “Ludwig-Aschoff House”, and then to Zurich in the mid-1980s where he became the founding director of the institute of neuropathology that I now have the privilege of chairing.

In order to prevent the danger of becoming stagnant in his science, he then took a long sabbatical at the laboratory of Angel Pellicer at Columbia University in the early 1990s, where he went back to the bench, pipetting proteins and preparing plasmids of activated oncogenes alongside graduate students. He returned to Zurich reinvigorated and started several new alleys of research. Only a few years later, however, he decided to innovate again his research (and his life) and accepted the position of director of the International Agency for Research on Cancer (IARC) of the World Health Organization in Lyon. At the same time, he became a successful entrepreneur in the business of scientific publishing, founding the journal Brain Pathology (now directed by Markus Glatzel), which he grew within a short time to an impressive two-digit impact factor. Brain Pathology is, to the present day, considered the premier journal in the discipline of molecular neuropathology.

I have admired the leadership skills of Paul Kleihues. In particularly, he firmly adhered to two principles – both of which I’m heeding to the present day. Firstly, he was convinced that the clinical service of diagnostic neuropathologists must go hand-in-hand with innovative, impactful research activities. He would only hire clinical residents who were genuinely interested in academic research, at a time when many of his colleagues would lead a strictly diagnostic practice separate from research activities (if any). Instead, Paul was convinced that such separation was doomed and would not allow fundamental research to be translated into actual medical advances. Secondly, Paul saw his institute primarily as a springboard for the careers of young scientists. He never egoistically held on to successful young coworkers, but rather encouraged them to move out of the institute into the “vast wild word”, thereby expanding their scientific horizon, enhancing their market value and improving their chances in the academic marketplace. And how successful was he with this strategy! By the year 2000, the majority of academic chairs of neuropathology in German-speaking countries (and beyond) were being held by alumni of Paul Kleihues.

When a distinguished academic scientist passes away, it is natural to ask the question of what he leaves behind. Paul Kleihues has not only created a body of scientific knowledge that is certain to outlast him, but he has also initiated a veritable school of neuropathologists, by contributing to the firm establishment of what used to be an appendix  to surgical pathology and by setting recognised standards in the diagnostic criteria, the training curricula and the leadership principles for academic neuropathology. The many successful alumni of his school, as well as the third generation of neuropathologists trained by those alumni, will always cherish his memory and are not going to forget his mentorship.

Paul Kleihues (rightmost, back row) and Adriano Aguzzi (leftmost, back row) in 1982. Other academic neuropathologists in this picture include Yannis Anagnostopoulos, Benedikt Volk, Otmar Wiestler, Marieke Kissling, Taichiro Shibata and Stephan Bamborschke.


Adriano Aguzzi
Editor in chief Swiss Medical Weekly
Institute Director, Institute of Neuropathology, UniversitätsSpital Zürich, Switzerland