Tenosynovial Giant Cell Tumor: Better molecular understanding revolutionizes treatment outcome

Abstract

Tenosynovial giant cell tumors (TGCTs) are rare tumors, which are primarily treated via surgery with a low likelihood of metastasis. Although wide excision is an excellent choice for local control, tumors located within or close to major joints, along with the benign nature of the disease, make such resection impractical. An increase in local recurrences and the need for multiple surgical procedures promoted the interest in targeted-therapies for this disease. TGCTs contain a mixture of giant cells, mononuclear cells and inflammatory cells, with clonal cytogenetic abnormalities through rearrangements involving 1p11-13. Colony stimulating factor (CSF1) gene encodes for the ligand of CSF1 receptor (CSF1R). The CSF1 gene is located at the chromosome 1p13 breakpoint and is found to be translocated in 63%-77% of patients with TGCTs. Selective CSF1R inhibitors yield high response rate and disease control, demo nstrating the integration of a new drug development technology that could revolutionize treatment outcomes.