Prognostic impact of IDH mutations in chondrosarcoma.

Abstract Background Mutant isocitrate dehydrogenase (IDH) in chondrosarcoma produces the oncometabolite 2-hydroxyglutarate (2-HG) and contributes to malignant progression, and is therefore a potential therapeutic target for chondrosarcoma. Robust historical control data are important in clinical trials of rare cancers such as chondrosarcoma in order to show a clear benefit of new drugs. However, it remains controversial whether IDH mutation status is associated with the clinical outcome of chondrosarcoma, and this hinders the development of mutant IDH inhibitors in clinical trials.background Methods We investigated the relationship between IDH gene status and clinicopathological data in 38 chondrosarcoma patients from whom frozen tumor samples were obtained at the time of biopsy or surgery. Targeted next-generation sequencing was also performed to compare genetic alterations between patients with and without IDH mutations.methods Results The results revealed 15 cases (40%) of heterozygous IDH1 mutations and five cases (13%) of IDH2 mutations. IDH-mutant chondrosarcoma was associated with worse overall survival than IDH–wild-type chondrosarcoma (IDH1/2 Mut vs. IDH Wt, P = 0.006; IDH1 Mut vs. IDH Wt, P = 0.030; IDH2 Mut vs. IDH Wt, P  Conclusion This study is the first to report in detail the characteristics and clinical courses of IDH-mutant chondrosarcoma patients in Japan. Our data suggested that IDH-mutant chondrosarcomas might have a worse prognosis than that of IDH-wild-type chondrosarcoma, possibly through the more aggressive characters after metastasis. This information will be useful for designing clinical trials of mutant IDH inhibitors for treatment of advanced chondrosarcoma.conclusion