Though the HT1080 cell line had originally been characterized as a fibrosarcoma, discovery of the endogenous IDH1 R132C mutation has led to speculation that it is more likely a de-differentiated chondrosarcoma, and thus here we will refer to this cell line as a chondrosarcoma model, rather than a fibrosarcoma model (27, 28). The gene discussed is IDH1; the disease is chondrosarcoma.