Ferry Ossendorp is investigating the immune system and cancer for more than 25 years. His main work focusses on basic research of the T cell immune system in many different aspects. These include studies to antigen uptake, processing and presentation to T cells, the biology of dendritic cells and the regulation of immunity which are aimed to raise our understanding of the immune reactions to tumor cells and improve immunotherapy of cancer. Recently, his findings were translated into an early clinical study in which cancer patients are injected with an experimental tumor-specific peptide-conjugate vaccine.