The WHO Classification of Genetic Tumour Syndromes: Considerations for Genetics.

The WHO Classification of Tumours is used widely by histopathologists and other disciplines as it provides an internationally agreed taxonomy of neoplastic disorders. Now published online and in print, it has often included genetic tumour syndromes (GTS) relevant to particular organs, as suggested by the editorial board. This highlighted the lack of a systematic classification of GTS, providing international standards for their diagnosis and a basis for research. The need for this was established by a series of meetings, leading to the adoption of a hierarchical classification of GTS based on the cellular mechanism affected, the molecular pathway involved, the clinical syndrome and the gene defects present. The major cellular mechanisms affected were identified as: growth factor receptors and related pathways; oxidative stress response and metabolism; cell cycle and apoptosis; DNA repair and genomic stability; telomere maintenance; epigenetic drivers and chromatin; RNA regulation and protein regulation. Assembly of the classification emphasised current gaps in knowledge, together with the need for further research. The new classification highlights the relationships between some genetic syndromes and provides an internationally agreed framework for the incorporation of new information as it becomes available.