On March 30, 2022, our honorary ESTP member, Professor Mohr, died at his home in Hannover, Germany, where he has lived with his family since 1976. He was buried in the family grave on April 13, 2022. Professor Mohr was born in 1931 in Frankfurt/Main and grew up in Frankfurt/Main and Munich.

After graduating from high school, he studied medicine in Munich, received his doctorate there (1958) and habilitated (1967) at the German Cancer Center in Heidelberg. His path to scientific success started here with the experimental proof of transplacental carcinogenesis.

In 1968 Prof. Mohr was appointed a full university professor and director of the Institute for Experimental Pathology at the Hannover Medical School. He held this position until 2000 when he retired. At that time his deep interest was in research of agents supposed to be carcinogenic to humans, in rodents for exploration and in vitro models with respiratory tissue. In 1981, Prof. Mohr was awarded with the German Research Prize for his work on the effects of PAHs on cell and organ cultures in vitro. He also paid particular attention to medical student training in histopathology. In addition to his duties at the Medical School Hannover, in 1982, he was a founding father of the Fraunhofer Institute of Aerosol Research in Hannover, which is located next to the university campus. After his retirement from the Hannover Medical school, Professor Mohr was a co-founder of the CULTEX labs (2007), which offered alternative techniques for exposure of cells to airborne pollutants, so that he could further pursue his scientific interests.

In 1978, Professor Mohr initiated and organized the annual ILSI Histopathology Seminars, which for nearly two decades provided training in laboratory animal pathology in Europe, the US and Japan, as a combination of oral presentations and glass slide seminars given by experts from all over the world. He also edited and co-edited a number of books essential in the field of toxicologic pathology with worldwide acceptance, such as the IARC WHO Monographs on "Pathology of Tumours in Laboratory Animals" – "Vol I Tumours of the Rat", "Vol 2 Tumours of the Mouse" and "Vol 3 Tumours of the Hamster", ten volumes of the "International Classification of Rodent Tumours, Part I - the Rat", and the textbook of the "International Classification of Rodent Tumours, the Mouse", as well as "Pathobiology of the Ageing Rat" and "Pathobiology of the Ageing Mouse". He was the editor of several monographs in the field of Inhalation Toxicology. His work contributed greatly to the training and continuing professional education of our membership.

As director of the Fraunhofer Institute of Toxicology and Aerosol Research, Professor Mohr initiated in 1987, jointly with represent-tatives of chemical and pharmaceutical industry, the RITA project, a database of peer reviewed spontaneous tumors occurring in laboratory animals. The RITA project was one of the main drivers in establishment of internationally harmonized diagnostic criteria for neoplasms in rodents (INHAND), and which has been used intensely to the benefit of our membership.

Professor Mohr was the co-editor of the journal "Experimental Pathology", and later editor in-chief of the journal "Experimental and Toxicologic Pathology", which was the official journal of the GTP for many years. He was author or co-author of more than 600 scientific publications and supervisor of more than 90 doctoral theses and 21 habilitations.

Professor Mohr received honorary doctorates from the University of Buenos Aires (Argentina), Barcelona (Spain), Kirov (Russia) and Chiang Mai (Thailand). In 2000, in recognition of his outstanding contributions to our society, Professor Mohr became honorary member of the GTP, which was transformed to the European Society of Toxicologic Pathology in 2002.

With Professor Mohr we have lost a scientist with outstanding contributions to the education in laboratory rodent pathology. Furthermore, and even more important than his scientific achievements, Ulrich Mohr was a warm hearted, approachable personality. His direct and positive attitude to help and support was always a personal guidance for young scientists. We will miss this outstanding scientist, teacher, mentor, and fellow human being!

Thomas Nolte (thomas.nolte@boehringer-ingelheim.com), Heinrich Ernst, Paul-Georg Germann, Susanne Rittinghausen