What’s New in Primary Malignant Musculoskeletal Tumors

Abstract

Malignant musculoskeletal tumors are infrequent and have relatively aggressive clinical courses. Systemic spread is common in higher grade tumors, and much of the basic research reviewed herein focuses on developing new systemic therapies to help prevent and treat metastatic disease. The clinical research reviewed here focuses on outcomes after local and systemic treatment of the tumors. We have added a section of reconstructive aspects of musculoskeletal oncology, which focuses on technical and mechanical issues. Chondrosarcoma has no characteristic molecular alteration, and thus a target for therapy is more challenging. ### Basic Science Work on the genetics of chondrosarcoma revealed mutations in the gene for type-II collagen (COL2A1) in 37% of the forty-nine cases studied. Further confirmation of previous reports on the presence of frequent mutations in isocitrate dehydrogenase 1 (IDH1) and IDH2 were also reported1. Another study reported the usefulness of IDH1 mutations in distinguishing chondrosarcoma from chondroblastic osteosarcoma, as the former had a mutation in IDH1 in 61% of patients whereas the latter had no mutations in IDH12. The bone morphogenetic protein pathway is active in central chondrosarcomas and the activity-correlated grade. This is the first time that the expression of this pathway was shown to correlate with grade3. Inhibitors of this pathway are available for early clinical trials. The transcription factor ETV5 has been linked to the regulation of matrix metalloproteinase-2 (MMP-2) in chondrosarcoma. It appears that ETV5 induces the expression of MMP-2, which degrades the surrounding matrix and thus allows chondrosarcoma cells to grow4. MMPs in cartilage tumors have been discussed as therapeutic targets for many years. ### Clinical Research Local recurrence of chondrosarcoma continues to be a focus of interest. Lin et al. reported the rate of survival after local recurrence as well as the rate of repeat local recurrences in patients with chondrosarcoma …