Research ArticleCancer Metastasis

Thymidine phosphorylase exerts complex effects on bone resorption and formation in myeloma

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Science Translational Medicine  24 Aug 2016:
Vol. 8, Issue 353, pp. 353ra113
DOI: 10.1126/scitranslmed.aad8949

Myeloma enzyme makes way for metastasis

Bone tissue is built up by osteoblasts and broken down by osteoclasts in a balanced remodeling process. In metastatic cancer, however, the balance is tipped, leading to the formation of cancerous growths in the bone. Attempts to prevent metastasis have not been successful in the clinic; thus, Liu and colleagues set out in search of a new pathway to target. The authors found that an enzyme produced by myeloma cells, called thymidine phosphorylase (TP), suppressed osteoblast activity (new bone formation) and enhanced osteoclast activity (bone resorption). Inhibiting TP reduced the incidence of myeloma-induced osteolytic bone lesions, suggesting a new target for translation to the clinic, especially because certain TP inhibitors are already approved for human use.