Another benefit to a liquid biopsy approach is that it would be expected to indirectly identify the presence of all oncogenic IDH1/2 mutations due to the conserved accumulation of D-2-HG across variants [226]; however, data in this respect is scarce due to the rarity of non-IDH1-R132H variants in glioma and the relatively small sample sizes of currently available studies. This evidence concerns the gene IDH1 and glioma.