Multiple studies report significant differences, but no specific FC, in R-2-HG levels between WT IDH1/2 and mutIDH1/2 glioma cells (U251, NHA, U87, and HOG),101,102,107,114,201 chondrosarcoma cells (L835, JJ012, SW1353, and L2975),202,203 glioma PDX mouse models,99 and glioma, chondrosarcoma, and AML PTBs8,106,116,124,204,205 and in plasma from individuals with ICC.206. The gene discussed is IDH1; the disease is central nervous system cancer.