IDH1 and neoplasm: Since HEK293 cells co-expressing IDH1-R132H-V5 with F-CIC or F-CIC-R201W produce less 2HG compared to the cells co-expressing IDH1-R132H-V5 and F-CIC-R1515H, it is tempting to speculate that in gliomas, missense mutations in the HMG domain alter its function to produce a 2HG level for tumour cells that balances cell survival and increased tumorogenicity, and for this reason such mutations are observed more frequently than missense mutations in the protein binding domains.