Cornelis Joseph Maria Melief (born 20 January 1943) is a Dutch immunologuist[1] specialising in cancer immunology and immunotherapy, with a focus on therapeutic cancer vaccines. He is emeritus Professor, former head of the Department of Immunohematology and Blood Transfusion at the Leiden University Medical Center,[1] and Chief Scientific Officer at ISA Therapeutics in Netherlands.[2] He is known for his work in the field of cancer immunology,[1] devising new cancer therapies based on the activation of the patient's own immune system.