[13] in 1986 and modified by Kaban et al. molecules that modulates T-cell responses. Questions/Purposes (1) Is an immune response elicited by giant cell lesions? (2) Do clinically relevant human leukocyte antigen (HLA) defects exist in giant cell lesions? (3) Is B7-H3 a clinically relevant immune modulator? Methods The study sample was derived from the population of patients presenting to the Massachusetts General Hospital for evaluation and management of giant cell lesions from 1993 to 2008. We included patients with histologically confirmed giant cell lesions with a minimum followup of 6?months. Patients with systemic diseases (n = 4 [3%]), syndromes associated with giant cell lesions (n = 4 [3%]), and those without sufficient followup (n = 26 [19%]), inadequate records (n = 7 [5%]), or inadequate tissue available (n = 2 [1%]) were excluded. Tissue microarray, containing 288 tissue cores for 93 patients, was carefully constructed. This contained tissue from 45 patients with maxillofacial lesions, 38 with aggressive and seven with nonaggressive lesions, and 48 patients with axial and appendicular lesions, 30 with aggressive lesions and 18 with nonaggressive lesions. The population mean age was 28 12?years and the duration of followup was 4 3?years. The tissue microarray was immunohistochemically stained with monoclonal antibodies specific for HLA classes I and II and B7-H3 antigens and analyzed for tumor infiltrating lymphocytes. Antigen expression was examined in multinucleated giant cells and mononuclear stromal cells. The results were correlated with local invasion and tumor aggressiveness, which is based on accepted staging criteria. Results Tumor infiltrating lymphocytes were detected in all the tumors. The mean number of CD8+ T cell infiltration was lower in aggressive tumors (median, 4.8; interquartile range [IQR], 0.4C13.4), when compared with nonaggressive tumors (median, 15.8; IQR, 4.3C46.3; p = 0.007). HLA class I antigens were highly expressed by multinucleated giant cells in all tumors, but were lightly expressed on mononuclear stromal cells in 53% (45 of 84) to 73% (56 of 77) of tumors. HLA class I antigen low expression in mononuclear stromal cells was associated with tumor aggressiveness (odds ratio [OR], 4.3; p = 0.005). Low HLA class I expression combined GDC-0152 with low CD8+ T cell infiltration was most highly associated with tumor aggressiveness (OR, 7.81; p = 0.011). B7-H3 antigen was expressed in 36.9% mononuclear stroma cells and also was associated with GDC-0152 local tumor invasion (OR, 1.36; p 0.001). Similarly, giant cell lesions with high B7-H3 expression and low CD8+ tumor infiltrating lymphocytes were associated with increased tumor aggressiveness (OR, 8.89; Rabbit Polyclonal to OR5W2 p = 0.0491). Conclusions Locally aggressive giant cell lesions are associated with low HLA class 1 antigen expression, low CD8+T cell infiltration, and high expression of the immune modulator B7-H3. Clinical Relevance Failure of immune surveillance implies that there may be an opportunity to target aspects of the immune surveillance machinery to treat giant cell lesions. Introduction Giant cell lesions of bone are relatively rare GDC-0152 tumors with low metastatic potential but they can be locally aggressive [2, 3, 29]. Giant cell lesions include central giant cell lesions of the maxillofacial skeleton and of the axial and appendicular skeleton [42]. Clinical and radiographic criteria are used to stratify giant cell lesions into aggressive and nonaggressive tumors as histologic criteria have not been correlated with tumor behavior [2, 18, 38]. Surgery remains the dominant approach but systemic therapy targeting receptor activator of nuclear factor kappa-B ligand (RANKL) with a monoclonal antibody (denosumab) has been shown to be an effective adjuvant [6]. However, the long-term effect of systemically targeting RANKL is poorly understood and it is not curative as giant cell lesions recur once the therapy is stopped [22]. This has prompted further investigation in the pathophysiology of giant GDC-0152 cell lesions with the hopes of identifying other targets. Histologically, there are mainly two cell populations in giant cell lesions that can act as potential targets for novel therapies. These are multinucleated osteoclastlike giant cells and mononuclear, spindle-shaped fibroblastlike, stromal cells [20, 23, 27]. Mononuclear stromal cells are thought to be the neoplastic cell as the multinucleated giant cells disappear with denosumab treatment yet the mononuclear stromal cells persist, and mononuclear stromal cells can be indefinitely propagated in culture [57]. For these reasons, it is useful to.