Giant cell tumor of bone: updated molecular pathogenesis and tumor biology.

Giant cell tumor of bone (GCTB)-related clonal aberrations occur in a background of epigenetic histone modifications (especially the G34W mutation of H3F3A gene) that induce cytogenetic abnormalities. Clonal aberrations are closely linked to the aggressiveness of GCTB. The "neoplastic" mononuclear stromal cells in GCTB express fundamental RANKLs and various chemokines and cytokines associated with monocyte recruitment and "reactive" multinucleated giant cells (osteoclastogenesis). The reciprocal and orchestrated actions between mononuclear stromal cells and multinucleated giant cells help in the understanding of the molecular pathogenesis and tumor biology of GCTB. In the future, novel targets in the updated tumor biology and molecular pathogenesis of GCTB should be explored and scrutinized for the development of systemic therapy.