IDH2 and chordoma: In that report, osteosarcoma samples from 222 patients, 19 osteosarcoma cell lines, and one chordoma cell line were tested for IDH1 mutations using the high-throughput MassARRAY platform: 64.4% (143 samples) of these were also analyzed for IDH2 mutations, including all chondroblastic osteosarcomas.