Immunohistochemical analysis of 1844 human epithelial and haematopoietic tumours and sarcomas for IDH1R132H mutation

Aims: Mutations in the isocitrate dehydrogenase 1 gene have been identified recently to play a key role in diffuse astrocytoma and oligodendroglioma as well as in acute myeloid leukaemia. In glioma, IDH1R132H is the most common mutation type, which is associated with younger patient age and longer patient survival compared to wild-type status. Sequencing analyses of carcinomas and lymphomas have detected IDH1 mutations in only a small fraction of cases. In those studies, IDH1R132H was also the most frequent mutation. The aim of the present study was to analyse a comprehensive series of human tumours for IDH1R132H mutation. Methods and results: A total of 1844 formalin-fixed paraffin-embedded tumours, including carcinomas, sarcomas and haematopoietic tumours were investigated immunohistochemically using a mutationspecific antibody for IDH1 R132H. Our positive control series consisted of a collection of diffuse astrocytomas and oligodendrogliomas. No IDH1R132H mutation was found in this series. Conclusions: IDH1R132H mutations occur almost exclusively in glioma and acute myeloid leukaemia.