Sticker's sarcoma (now known as CTVT for canine transmissible venereal tumour) is a histiocytic venereal tumour transmitted among dogs through direct contact. Recently, it has become evident that all tumours of this type existing worldwide originate from the tumour of one animal. The infectious agent that is transmitted through contact is the cancer cell itself. Sticker's sarcoma is the oldest recognised cancer line and is currently also the best model for infectious cancer cells. The sarcoma is named after the German veterinarian and physician Anton Sticker (1861-1944), who between 1902 and 1905 carried out extensive studies on the nature of this tumour at the institute headed by Paul Ehrlich in Frankfurt am Main. Sticker's hitherto relatively unknown, multifaceted career is briefly presented here.