Q (sonnet): what do idh1 mutations do?

═ answer (success)
IDH1 (isocitrate dehydrogenase 1) mutations are recurrent, well-characterized cancer alterations, most notably in gliomas, acute myeloid leukemia (AML), and chondrosarcoma. A brief, general (non-cBioPortal-data) summary:

- **Location**: The vast majority of cancer-associated IDH1 mutations occur at a single hotspot residue, **R132** (e.g., R132H, R132C), in the enzyme's active site.
- **Mechanism**: Wild-type IDH1 normally converts isocitrate to α-ketoglutarate (α-KG). Mutant IDH1 acquires a novel enzymatic activity that instead converts α-KG into the oncometabolite **D-2-hydroxyglutarate (2-HG)**.
- **Downstream effect**: 2-HG accumulates to high levels and competitively inhibits α-KG-dependent dioxygenases, including enzymes involved in DNA and histone demethylation (e.g., TET2, histone demethylases). This leads to widespread epigenetic dysregulation — a hypermethylation phenotype — that impairs normal cellular differentiation and contributes to tumorigenesis.
- **Clinical relevance**: IDH1 mutation status is used diagnostically to classify gliomas (IDH-mutant vs. IDH-wildtype, per WHO CNS tumor classification) and is generally associated with a more favorable prognosis in glioma compared to IDH-wildtype tumors. IDH1 mutations are also a target for specific inhibitor therapies (e.g., ivosidenib) in AML and cholangiocarcinoma.

This is general background knowledge, not derived from cBioPortal data.

If you'd like, I can pull actual IDH1 mutation frequency and variant-level data (e.g., R132H vs. other substitutions) from specific cBioPortal cohorts such as glioma or AML studies, and link you directly to the relevant OncoPrint or mutations view. Just let me know which cancer type or study you're interested in.