Between 1997 and 2001 he worked at the Fred Hutchinson Cancer Research Center, Seattle, USA, on adoptive immunotherapy for infectious disease and cancer. After returning to Tuebingen, his group focused on developing immunotherapy protocols for both infectious disease and cancer with the focus on B-cell malignancies. After transferring to University Hospital of Wuerzburg, he was appointed a consultant and became head of hematology in 2014. Professor Topp has published more than 55 original papers in journals such as Lancet Oncology, JCO, Blood and others. He pioneered the first immunotherapy drug for the treatment of acute leukemias. He received his medical degree at the Berlin Medical School in Germany and had his medical training at the Berlin Medical School and the University Hospital of Tuebingen (both in Germany).