The World Health Organization’s Programme for the Histopathoiogical Definition and Classification of Tumours

A brief description is given of the efforts of the World Health Organization to facilitate international communication and comparability of data in oncology by developing uniform classifications and nomenclatures for the microscopic definition of tumours. This has involved the collaboration of over 200 pathologists in 46 countries, in a network of 19 International Reference Centres. Ten of these Centres have already completed their work. Reports have begun to appear in the literature of studies based on the classifications they have prepared.