IDH1 and osteosarcoma: The 96 archived FFPE samples of ICHTs (chondrosarcoma, chordoma, osteosarcoma, chondroma, and chondromyxoid fibroma) were tested for the presence of IDH1 mutations using three methods: biochip assay, qPCR-DMA with the TaqMan probe followed by sequencing of IDH1-positive samples, and IHC with IDH1-specific polyclonal antibodies.