Clinicopathologic profile of 470 giant cell tumors of bone from a cancer hospital in western India

MiR-126-5p regulates osteolysis formation and stromal cell proliferation in giant cell tumor through inhibition of PTHrP

Parathyroid hormone-related protein (PTHrP) has been identified to play a crucial role in osteolysis formation and stromal cell (GCTSC) proliferation in giant cell tumor (GCT). MiR-126-5p is an intronic miRNA identified as tumor suppressor in many tumors, but its role in GCT is poorly understood. We found that miR-126-5p was decreased in GCT and could directly regulate PTHrP expression. Furthermore, miR-126-5p could control osteoclast (OC) differentiation, GCTSC proliferation and osteolysis formation in GCT through negative regulation of PTHrP. Thus, these results suggest that miR-126-5p could directly target PTHrP and have a tumor suppressor function in GCT.

Pulmonary metastasis of giant cell tumor of bones

Giant cell tumor of bone (GCTB) accounts for 5% of primary skeletal tumors. Although it is considered to be a benign lesion, there are still incidences of pulmonary metastasis. Pulmonary metastasis of GCTB may be affected by tumor grading and localization as well as the age, gender and overall health status of the patient. Patients with local recurrence are more likely to develop pulmonary metastasis of GCTB. High expression of some genes, cytokines and chemokines may also be closely related to the metastatic potential and prognosis of GCTB. The treatment of the primary GCTB is key to the final outcome of the disease, as intralesional curettage has a significantly higher local recurrence and pulmonary metastasis rate than wide resection. However, even patients with pulmonary metastasis seem to have a good prognosis after timely and appropriate surgical resection. It is hoped that with the development of novel surgical methods and drugs, pulmonary metastasis of GCTB can be prevented and treated more effectively.

Epigenetic silencing of genes and microRNAs within the imprinted Dlk1-Dio3 region at human chromosome 14.32 in giant cell tumor of bone

BACKGROUND

Growing evidence exists that the neoplastic stromal cell population (GCTSC) within giant cell tumors (GCT) originates from mesenchymal stem cells (MSC). In a previous study we identified a microRNA signature that differentiates between these cell types. Five differentially expressed microRNAs are located within the Dlk1-Dio3 region on chromosome 14. Aberrant regulation within this region is known to influence cell growth, differentiation and the development of cancer. The aim of this study was to elucidate the involvement of deregulations within the Dlk1-Dio3 region in GCT pathogenesis.

METHODS

Quantitative gene and microRNA expression analyses were performed on GCTSCs and MSCs with or without treatment with epigenetic modifiers. Methylation analysis of differentially methylated regions was performed by bisulfite sequencing.

RESULTS

In addition to microRNA silencing we detected a significant downregulation of Dlk1, Meg3 and Meg8 in GCTSCs compared to MSCs. DNA methylation analyses of the Meg3-DMR and IG-DMR revealed a frequent hypermethylation within the IG-DMR in GCTs. Epigenetic modification could restore expression of some but not all analyzed genes and microRNAs suggesting further regulatory mechanisms.

CONCLUSION

Epigenetic silencing of genes and microRNAs within the Dlk1-Dio3 region is a common event in GCTSCs, in part mediated by hypermethylation within the IG-DMR. The identified genes, micro RNAs and microRNA target genes might be valuable targets for the development of improved strategies for GCT diagnosis and therapy.

The hypermetabolic giant: 18F-FDG avid giant cell tumor identified on PET-CT

An 87 year-old white female presented with a two-year history of intermittent discomfort in her left foot. PET-CT identified intense18F-fluorodeoxyglucose (FDG) uptake corresponding to the lesion. Histology of a fine needle aspiration and open biopsy were consistent with a benign giant cell tumor (GCT) of the bone. GCT of bone is an uncommon primary tumor typically presenting as a benign solitary lesion that arises in the end of the long bones. While GCT can occur throughout the axial and appendicular skeleton, it is exceedingly uncommon in the bone of the foot. While 18F-FDG has been established in detecting several malignant bone tumors, benign disease processes may also be identified. The degree of 18F-FDG activity in a benign GCT may be of an intensity that can be mistakenly interpreted as a malignant lesion. Therefore, GCT of the bone can be included in the differential diagnosis of an intensely 18F-FDG-avid neoplasm located within the tarsal bones.

Identification of differentially expressed genes and their subpathways in recurrent versus primary bone giant cell tumors

Giant cell tumor (GCT) of the bone is a benign but locally aggressive bone neoplasm with a strong tendency to develop local recurrent and metastatic disease. Thus, it provides a useful model system for the identification of biological mechanisms involved in bone tumor progression and metastasis. This study profiled 24 cases of recurrent versus primary bone GCT tissues using QuantiGene 2.0 Multiplex Arrays that included Human p53 80-Plex Panels and Human Stem Cell 80-Plex Panels. A total of 32 differentially expressed genes were identified, including the 20 most upregulated genes and the 12 most downregulated genes in recurrent GCT. The genes identified are related to cell growth, adhesion, apoptosis, signal transduction and bone formation. Furthermore, iSubpathwayMiner analyses were performed to identify significant biological pathway regions (subpathway) associated with this disease. The pathway analysis identified 11 statistically significant enriched subpathways, including pathways in cancer, p53 signaling pathway, osteoclast differentiation pathway and Wnt signaling pathway. Among these subpathways, four genes (IGF1, MDM2, STAT1 and RAC1) were presumed to play an important role in bone GCT recurrence. The differentially expressed MDM2 protein was immunohistochemically confirmed in the recurrent versus primary bone GCT tissues. This study identified differentially expressed genes and their subpathways in recurrent GCT, which may serve as potential biomarkers for the prediction of GCT recurrence.

MiR-126-5p regulates osteoclast differentiation and bone resorption in giant cell tumor through inhibition of MMP-13

Giant cell tumor (GCT) of bone is an aggressive skeletal tumor characterized by localized bone resorption. Matrix metalloproteinase-13 (MMP-13) is the principal proteinase expressed by the stromal cells of GCT (GCTSCs) and also considered to play a crucial role in formation of the osteolytic lesion in GCT. However, the exact mechanism of the regulation of MMP-13 expression in GCTSCs was unknown. In this study, we identified miR-126-5p was significantly downregulated in GCTSCs and affect osteoclast (OC) differentiation and bone resorption by repressing MMP-13 expression at the post-transcriptional level. Thus, our studies show that miR-126-5p plays an important physiological role in multinucleated giant cell formation and osteolytic lesion in GCT.

Retrospective analysis of patients with rare-site and metastatic giant cell tumor

A giant cell tumor occurs mainly in the proximal tibia, humerus, distal radius bone and the pelvic bone. It is rarely observed in such sites as the ribs and the temporal bone. The condition is primarily treated with surgical excision and functional reconstruction. The effect of chemotherapy on lung metastases and locally advanced giant cell tumors has remained unknown. We collected and analyzed the data of six patients with rare giant cell tumors located in the head and neck patients. After an average follow-up of 42.6 months after surgery (14 to 90 months), no local recurrence or metastasis was observed. We also collected and analyzed the data of five patients with metastatic giant cell tumors who were undergoing surgery for the primary tumor before; of three patients who had experienced multiple chemotherapy cycles, one had spontaneous regression, and one survived for long timer despite progression. The other two patients had their major metastatic lesions resected by surgery, and presented long-term survival during the follow up. In addition, this study reports one patient with locally advanced giant cell tumor of the rib, who has undergone successful surgical resection following two cycles of chemotherapy with ifosfamide and liposomal doxorubicin. Complete resection of the lesion at the head and neck is the key to relapse-free survival. The prognosis of lung metastases in patients with giant cell tumors is relatively satisfying. Neoadjuvant chemotherapy is also conducive to the surgery for locally advanced lesions and improvement of the quality of life.

Targeting the giant cell tumor stromal cell: functional characterization and a novel therapeutic strategy

Giant cell tumor of bone (GCTB) is a benign, locally destructive neoplasm, with tumors comprised of mesenchymal fibroblast-like stromal cells; monocytic, mononuclear cells of myeloid lineage; and the characteristic osteoclast-like, multinucleated giant cells. Hampering the study of the complex interaction of its constituent cell types is the propensity of longstanding, repeatedly passaged cell cultures to undergo phenotypic alteration and loss of osteoclast-inducing capacities. In this study, we employed a novel, single-step technique to purify freshly harvested stromal cells using a CD14-negative selection column. Using 9 freshly harvested GCTB specimens and the purified stromal cell component, we performed analyses for markers of osteoblast lineage and analyzed the capacity of the stromal cells to undergo osteoblastic differentiation and induce osteoclastogenesis in co-cultures with monocytic cells. Successful purification of the CD14-negative stromal cells was confirmed via flow cytometric analysis and immunocytochemistry. Osteogenic media upregulated the expression of osteocalcin, suggesting an osteoblastic lineage of the GCTB stromal cells. The effects of the Wnt pathway agonist, SB415286, and recombinant human bone morphogenetic protein (BMP)-2 on osteoblastogenesis varied among samples. Notably, osteogenic media and SB415286 reversed the receptor activator of NF-κB ligand (RANKL)/osteoprotegerin (OPG) expression ratio resulting in diminished osteoclastogenic capacity. Recombinant human BMP2 had the opposite effect, resulting in enhanced and sustained support of osteoclastogenesis. Targeting the giant cell tumor stromal cell may be an effective adjunct to existing anti-resorptive strategies.

Safety and efficacy of denosumab for adults and skeletally mature adolescents with giant cell tumour of bone: interim analysis of an open-label, parallel-group, phase 2 study

BACKGROUND

Giant cell tumour of bone (GCTB) is a very rare, aggressive, and progressive osteolytic tumour for which no standard medicinal treatment or chemotherapy exists. We report interim safety and efficacy results from a phase 2 study of denosumab in patients with GCTB.

METHODS

We did an international, open-label, parallel-group, phase 2 trial of patients with histologically confirmed GCTB and radiographically measurable active disease. Eligible patients were adults or skeletally mature adolescents with radiographic evidence of at least one mature long bone who were at least 12 years old and weighed at least 45 kg. We divided patients into three cohorts--those with surgically unsalvageable GCTB (cohort 1), those with salvageable GCTB whose surgery was associated with severe morbidity (cohort 2), and those who transferred from a previous study of denosumab for GCTB (cohort 3). Patients in cohorts 1 and 2 received 120 mg of subcutaneous denosumab every 4 weeks with loading doses on days 8 and 15 of the first cycle; those in cohort 3 continued the regimen from the previous study. Investigator-determined disease status and clinical benefit were assessed every 4 weeks. Our primary endpoint was the safety profile of denosumab in terms of adverse events and laboratory abnormalities. Prespecified secondary endpoints were time to disease progression in cohort 1 and the proportion of patients without any surgery at 6 months in cohort 2. Safety analyses included all patients who received at least one dose of denosumab. Efficacy analyses included all eligible patients who received at least one dose of denosumab. This study is registered with ClinicalTrials.gov, identifier NCT00680992.

FINDINGS

282 patients, including ten adolescents, were included between Sept 9, 2008, and March 25, 2011. Of the 281 patients analysable for safety, three (1%) had osteonecrosis of the jaw and 15 (5%) hypocalcaemia. The most common grade 3-4 adverse events were hypophosphataemia, which occurred in nine (3%) patients, and anaemia, back pain, and pain in extremities, each of which occurred in three patients (1%). Serious adverse events were reported in 25 (9%) patients. No treatment-related deaths were reported. On the basis of investigators' assessment of disease status, 163 of 169 (96%) analysable patients in cohort 1 had no disease progression after median follow-up of 13 months (IQR 5·8-21·0). In cohort 2, 74 of 100 (74%) analysable patients had no surgery and 16 of 26 (62%) patients who had surgery underwent a less morbid procedure than planned. Median follow-up in cohort 2 was 9·2 months (IQR 4·2-12·9).

INTERPRETATION

Adverse events were consistent with the known safety profile of denosumab. Denosumab was associated with tumour responses and reduced the need for morbid surgery in patients with GCTB. Denosumab represents a new treatment option for patients with GCTB.

FUNDING

Amgen.

A retrospective analysis of 140 patients with giant cell tumor in the extremity: a multicenter study based on four hospitals in South China

BACKGROUND

Update reports are rarely available regarding the bone giant cell tumors (GCTs) in the extremity in Chinese people. The aim of this study was to review the epidemiological characteristics of bone GCT in the extremity based on the clinical data from four hospitals in South China.

METHODS

We searched medical electronic records from January 2001 to December 2011 in four hospitals in South China to identify patients with definite diagnosis of extremity GCT. Epidemiological data including gender, tumor site, age at the time of first diagnosis, local recurrence and pulmonary metastasis were collected and analyzed statistically. Differences between-genders were particularly analyzed regarding first diagnosis age, tumor site, local recurrence and pulmonary metastasis. T-test and Chi-square test were used for continuous and dichotomous variables, respectively.

RESULTS

A total of 140 GCT patients (87 males and 53 females) were identified. The gender ratio was 1.64 for a male predominance. GCTs were mostly located around the knee (67 cases). 92 patients were in their 20s to 40s upon first diagnosis. The average age at the time of first diagnosis for all was 30.49 years, 30.76 years for males and 30.06 years for females (P = 0.757). GCT recurred locally in 50 patients (26 males and 24 females) with no gender difference (P = 0.065). The average interval from first surgery to local recurrence was 21.42 months. Pulmonary metastasis was found in 11 patients (8 males and 3 females) also with no gender difference (P = 0.667). The average interval from first diagnosis to metastasis was 36.45 months.

CONCLUSIONS

Extremity GCT may have a male predominance in Chinese population and mostly occur at 20-40 years of age and around the knee. Follow-ups for GCT patients should be carried on for at least 3 years after primary surgery according to the average intervals for possible local recurrence and pulmonary metastasis.

Giant cell tumor of bone: a basic science perspective

Comprehending the pathogenesis of giant cell tumor of bone (GCT) is of critical importance for developing novel targeted treatments for this locally-aggressive primary bone tumor. GCT is characterized by the presence of large multinucleated osteoclast-like giant cells distributed amongst mononuclear spindle-like stromal cells and other monocytes. The giant cells are principally responsible for the extensive bone resorption by the tumor. However, the spindle-like stromal cells chiefly direct the pathology of the tumor by recruiting monocytes and promoting their fusion into giant cells. The stromal cells also enhance the resorptive ability of the giant cells. This review encompasses many of the attributes of GCT, including the process of giant cell formation and the mechanisms of bone resorption. The significance of the receptor activator of nuclear factor-κB ligand (RANKL) in the development of GCT and the importance of proteases, including numerous matrix metalloproteinases, are highlighted. The mesenchymal lineage of the stromal cells and the origin of the hematopoietic monocytes are also discussed. Several aspects of GCT that require further understanding, including the etiology of the tumor, the mechanisms of metastases, and the development of an appropriate animal model, are also considered. By exploring the current status of GCT research, this review accentuates the significant progress made in understanding the biology of the tumor, and discusses important areas for future investigation.

Giant-cell tumor of bone, anti-RANKL therapy

Giant-cell tumor of bone (GCTB) is a rare osteolytic tumor of the bone. Although classified as a benign tumor, GCTB is characterized by local aggressiveness and risk of local recurrence. In addition, GTCB can in some cases lead to the development of so-called 'benign' chest metastases. Surgical resection by intralesional curettage with high-speed burring and polymethylmethacrylate cement is the standard treatment for resectable tumors. In cases of metastatic or unresectable disease (when planned surgical procedure is impossible or would result in severe morbidity), medical treatments such as cytotoxic chemotherapy or interferon-α have limited efficacy. Bisphosphonates have been proposed as a therapeutic option to reduce osteoclast activity. In bone, various pathological states may result from an imbalance in the RANK (receptor activator of nuclear factor kappa-B)/RANKL (receptor activator of nuclear factor kappa-B ligand)/OPG (osteoprotegerin) pathway. Involvement of the RANKL pathway in pathogenesis of GCTB was first proposed in 2000. Denosumab is a fully human monoclonal antibody that binds and inhibits RANKL, thereby preventing the activation of the RANK pathway. As it showed the possibility to counteract osteoclast activation in GCTB and prevent the known physiopathological role of RANKL, denosumab has been under evaluation in the clinic as a treatment for GCTB since 2005. Results of a first Phase II trial demonstrate the therapeutic potential of denosumab to inhibit progressive bone destruction and metastatic progression in patients with unsalvageable giant-cell tumor (GCT), and have also provided key insights into the biology of GCT. Denosumab is currently a therapeutic option for patients with unresectable GCTB but its place in the global therapeutic strategy has not yet been defined.

Giant cell tumor of the extremity: retrospective analysis of 621 Chinese patients from one institution

BACKGROUND

There are no recent reports of giant cell tumors of bone in a large series of Chinese people. The present study was designed to review the epidemiological characteristics and outcomes of surgical management in a large series of Chinese patients with giant cell tumor of an extremity, treated at a single institution.

METHODS

The records and images of 621 patients in whom a benign giant cell tumor in an extremity was treated between 1989 and 2009 were reviewed retrospectively. There were 359 male and 262 female patients. The mean age at diagnosis was 31.4 years (range, eleven to seventy-one years). Sixty-six percent of the giant cell tumors were localized around the knee. Surgical treatments primarily included curettage, extensive curettage, and resection. The median duration of follow-up was forty-nine months (range, eighteen to 256 months).

RESULTS

Giant cell tumor accounted for 13.7% of all primary bone tumors treated at our institution. Multivariate Cox regression analysis indicated that the only variable that contributed to recurrence-free survival was the type of surgical treatment. The local recurrence rate after extensive curettage was 8.6%, which was significantly lower than the 56.1% recurrence rate after curettage alone. Bone-grafting did not affect local tumor control after extensive curettage; the local recurrence rate was 11.1% if bone graft was used. Recurrent giant cell tumor can be treated by further curettage or resection, with acceptable re-recurrence rates of 6.7% and 9.3% respectively. The Musculoskeletal Tumor Society Score for patients treated with extensive curettage was 92.6%, which was significantly higher than that for patients treated with resection. Twenty-one (3.4%) of the 621 patients developed benign pulmonary metastasis, with a favorable outcome, and three patients presented with multifocal giant cell tumors.

CONCLUSIONS

The incidence of giant cell tumor in the Chinese population may be higher than that in Western countries, and it has a male predilection. The results of the present study suggest that extensive curettage provides favorable local control and satisfactory functional outcomes.

A microRNA signature differentiates between giant cell tumor derived neoplastic stromal cells and mesenchymal stem cells

Giant cell tumor (GCT) derived stromal cells (GCTSCs) have been identified as the neoplastic cell population of GCTs. Within these stromal cells a subpopulation has been identified that shares several features with mesenchymal stem cells (MSCs) indicating that these neoplastic cells develop from MSCs. Although spontaneous transformations of MSC have already been observed in vitro and in vivo the underlying molecular mechanisms are poorly understood. As microRNAs are crucially involved in tumorigenesis and the modulation of stem cell fate and behavior, they represent promising candidates for the regulation of this process. Therefore, the aim of this study was the comparative analysis of the microRNA expression profiles of GCTSCs and MSCs in order to identify differentially expressed microRNAs and their target genes. We could identify a microRNA signature consisting of 26 differentially expressed microRNAs that perfectly separates these two cell types. One of the microRNAs with the most pronounced differences in expression levels was miR-224. We could confirm the already known regulation of the apoptosis inhibitor API5 by miR-224 and could further identify three novel miR-224 target genes (SMAD5, SLMAP, H3.3B). The involvement of these genes in the regulation of apoptosis resistance, proliferation, differentiation and the regulation of gene transcription suggests pivotal roles of these genes in the neoplastic transformation of MSCs during GCT development.

Giant cell tumors that originated in the sternum

Giant cell tumors originating from the sternum are rare. We report a case of a giant cell tumor of the sternum with radiological evidence of aggressiveness. A 34 year-old woman noted a mass in the anterior chest wall that had been slowly growing over 1 year. After incision biopsy revealed a diagnosis of a giant cell tumor she was treated by surgical resection (subtotal sternectomy) and reconstruction with methylmethacrylate. The tumor was 14×9×8 cm, and histological study confirmed that it was a giant cell tumor. Although giant cell tumors are benign, they are locally aggressive lesions and must be considered in the differential diagnosis in patients with a sternal mass.

Evidence for the role of matrix metalloproteinase-13 in bone resorption by giant cell tumor of bone

Giant cell tumor of bone (GCT) is an aggressively osteolytic primary bone tumor that is characterized by the presence of abundant multinucleated osteoclast-like giant cells, hematopoietic monocytes, and a distinct mesenchymal stromal cell component. Previous work in our laboratory has shown that matrix metalloproteinase (MMP)-13 is the principal proteinase expressed by the stromal cells of GCT. The release of cytokines, particularly interleukin-1beta, by the giant cells of GCT acts on stromal cells to stimulate a surge in MMP-13 secretion. The purpose of this study was to determine the bone resorption capabilities of the cellular elements of GCT and the significance of the MMP-13 expression involved in GCT bone resorption. We present a 3-dimensional histomorphometric technique developed to analyze resorption pit depth and yield an accurate measurement of bone resorption with a direct physical view of lacunae on bone slices. In this study, we demonstrate that the mesenchymal stromal cells and the multinucleated giant cells of GCT are independently capable of bone resorption. However, coculture of these 2 cell fractions shows a synergistic increase in bone resorption. In addition, inhibition of MMP-13 reduces resorptive activity of the cells indicating that MMP-13 likely plays an important role in this tumor. This cell-cell cooperation involves giant cell-derived cytokine up-regulation of MMP-13 in the stromal cells, which in turn assists the giant cells in bone resorption. Future research will involve elucidation of the role of cell-cell/matrix communication pathways in bone resorption and tumorigenesis in GCT.

Metastatic giant cell tumor of bone: are there associated factors and best treatment modalities?

Giant cell tumors of bone are sometimes locally aggressive and may metastasize, although uncommonly. We attempted to identify associations of clinical and histopathologic parameters with metastasis, the long-term outcome with metastases, and the best treatment. We identified distant metastases in 24 of 470 patients with giant cell tumors during a 20-year period. The median age of these 24 patients at presentation was 26 years (range, 16-76 years), and the male:female ratio was 1.6:1, with no predilection for primary site. Metastasis occurred at a mean of 2 years (range, 4 months-11 years) after initial diagnosis. Sites for distant metastases were the lung (21 of 24 patients), scalp, calf muscle, and regional lymph nodes. The 24 patients had a mean followup of 3.5 years (range, 0-16 years). Thirteen of the 24 patients has local recurrence before or at the time of metastasis. Two patients refused treatment, eight underwent metastasectomy, and 14 were inoperable (four had chemotherapy, 10 were treated symptomatically). We observed disease progression with hemoptysis in one of 14 patients. None of the patients died of their metastatic disease. None of the risk factors we studied was associated with metastasis in giant cell tumors. Although the overall outcome was favorable, metastasectomy is recommended where feasible.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

[Pathologic fracture of the distal femur in total knee arthroplasty. Polyethylene-wear-induced osteolysis? A case report]

Malignant bone tumors and osteitis of the distal femur are common at every age. These conditions must be considered in patients with total knee arthroplasty and suspicious x-rays. A patient with gross polyethylene-wear-induced osteolysis and periprosthetic fracture is described. Neoplasm and infectious granuloma were excluded through biopsy, and the bone defect was bridged with a rotating hinged distal femoral replacement.