Sclerostin immunohistochemical staining in surgically treated giant cell tumor of bone.

Abstract

Giant cell tumor of bone (GCTB) is a destructive lesion with a high potential for recurrence. RANK-ligand targeted therapy has provided promising, yet mixed results. Sclerostin (SOST) inhibition results in a net anabolic response and is currently used in the treatment of osteoporosis. The application to GCTB is unknown. We sought to determine if GCTB stained for SOST on immunohistochemistry and correlate its expression with predictor variables. All patients at a single institution undergoing surgery for GCTB between 1993 and 2008 with a minimum of 6 months follow-up were included. Primary outcomes included the presence of SOST staining, secondary outcomes included the correlation of patient and tumor-specific predictor variables. SOST antibody staining of any cell type was present in 47 of 48 cases (97.9%). Positivity of the stromal cells was present in 39 of 48 cases (81.3%) and was associated with radiographic aggressiveness (p = 0.023), symptomatic presentation (p = 0.032), prior surgery (p = 0.005), and patient age (p = 0.034). Positivity of giant cells was present in 41 of 48 cases (85.4%) and was not significant with predictive factors. Sclerostin staining in GCTB is a novel finding and warrants further research to define the role of sclerostin as a prognostic factor and therapeutic target.