Marnix Jansen, MD, PhD, is a Cancer Research UK (CRUK) clinician scientist and consultant histopathologist at University College Hospital and UCL Cancer Institute. Dr Jansen originally trained as a molecular biologist and obtained his PhD in the laboratory of Prof Hans Clevers at the Hubrecht Institute for Stem Cell Research and then pursued clinical training in histopathology at the Academic Medical Center (AMC) in Amsterdam, the Netherlands. After obtaining a Translational Cancer Research Fellowship awarded by the Dutch Cancer Society (KWF), he moved to the laboratory of Nick Wright at Barts Cancer Institute in London. He has also undertaken combined clinical and research training at the Johns Hopkins Medical Institutes in Baltimore, US and the National Cancer Centre Hospital in Tokyo, Japan. His current work focuses on stem cell evolution in Barrett’s dysplasia and risk stratification in early-stage oesophageal adenocarcinoma.