D2HGDH and breast neoplasm: In the context of breast tumors, however, mutations in IDH enzymes have not been identified, which is why alternative mechanisms of 2HG accumulation are being discussed (e.g. alcohol dehydrogenase, iron containing 1 (ADHFE1) overexpression or D-2-hydroxyglutarate dehydrogenase (D2HGDH) downregulation) [41].