PD Dr. med. Alexander Siebenhüner is Head of Gastrointestinal Oncology and a Member of the Executive Board of the Hirslanden Cancer Institute at Klinik Hirslanden Zürich, Switzerland. His clinical and translational work focuses on biomarker-driven treatment of gastrointestinal cancers, including CLDN18.2-targeted therapy, HER2, dMMR/MSI-H tumours, ctDNA-based minimal residual disease detection, antibody–drug conjugates, FGFR2 and KRAS inhibition. He chairs the GI Group of the Swiss Group for Clinical Cancer Research (SAKK) and the Young Investigator Group of the EORTC Gastrointestinal Tract Cancer Group, and he chairs the board of SwissNET, the Swiss neuroendocrine tumour network. He also conducts implementation science research in prevention at the Epidemiology, Biostatistics and Prevention Institute (EBPI), University of Zurich. He welcomes collaboration on clinical trials and translational projects in GI oncology.