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In rare cases, giant cell tumor of bone (GCTB) can undergo primary or secondary malignant transformation to malignant giant cell tumor of bone (MGCTB), but the details of the molecular alterations are still unclear. The present study aimed to elucidate the clinicopathologic and molecular features of MGCTBs based on immunohistochemistry, fluorescence in situ hybridization (FISH) and next generation sequencing (NGS) of nine MGCTBs (five primary and four secondary). Seven (78%) of 9 MGCTBs were immunohistochemically positive for H3.3 G34W. In two (22%) patients, although GCTB components were focally or diffusely positive for H3.3 G34W, their malignant components were entirely negative for H3.3 G34W, which was associated with heterozygous loss of H3F3A by FISH. NGS on four MGCTBs revealed pathogenic mutations in TP53 (n = 3), EZH2 (n = 1) and several other genes. Immunohistochemical analysis of the nine MGCTBs confirmed the p53 nuclear accumulation (n = 5) and loss of H3K27me3 expression (n = 3) and showed that they were mutually exclusive. In addition, four (80%) of five cases of pleomorphic or epithelioid cell-predominant MGCTBs were positive for p53, while three (75%) of four cases of spindle cell-predominant MGCTBs were negative for trimethylation at lysine 27 of histone 3 (H3K27me3). The results suggested that p53 alteration and dysfunction of histone methylation as evidenced by H3K27me3 loss may play an important role in the malignant progression of GCTB, and might contribute to the phenotype-genotype correlation in MGCTB. The combined histologic, immunohistochemical and molecular information may be helpful in part for the diagnosis of challenging cases.

Due to the wide variations in location, size, local invasiveness, and treatment options, the complications associated with surgery for giant cell tumor of bone have been sporadically reported. For quality assessment, fundamental data based on large-scale surveys of complications under a universal evaluation system is needed. The Dindo-Clavien classification is an evaluation system for complications based on severity and required intervention type and is suitable for the evaluation of surgery in a heterogeneous cohort.A multi-institutional retrospective survey of 141 patients who underwent surgery for giant cell tumor of bone in the extremity was performed. The incidence and risk factors of complications, type of intervention for complication control, and impact of complications on functional and oncological outcomes were analyzed using the Dindo-Clavien classification.Forty-six cases (32.6%) had one or more complications. Of them, 18 (12.8%), 11 (7.8%), and 17 (12.1%) cases were classified as Dindo-Clavien classification grade I, II, and III complications, respectively. There were no cases with grade IV or V complications. Progression in Campanacci grading (p = 0.04), resection (over curettage, p 0.0001), reconstruction with prosthesis (p = 0.0007), and prolonged operative duration (p = 0.0002) were significant risk factors for complications. Complications had a significant impact on function (p 0.0001). Differences in the impact of complication types and tumor location on function were confirmed. Complications had no impact on local recurrence and metastasis development.The Dindo-Clavien classification could provide fundamental information, under a uniform definition and classification system, on postoperative complications in patients with giant cell tumor of bone in terms of incidence, type of intervention for complication control, risk factors, and impact on functional outcome. The data are useful not only for preoperative evaluation for the risk of complications under specific conditions but also for quality assessment of surgery for giant cell tumor of bone.

The term giant cell-rich tumors of bone refers to a shared morphologic pattern in a group of different osseous lesions, that is, the abundance of osteoclastlike giant cells. Fitting with a broad spectrum of clinical presentations and biological behavior, the recent detection of characteristic molecular alterations in giant cell tumor of bone (H3-3), nonossifying fibroma (KRAS, FGFR1), giant cell granuloma of the jaws (KRAS, FGFR1, TRPV4), and aneurysmal bone cyst (USP6) have contributed significantly to the biological understanding of these morphologically related but clinically distinct lesions and their systematic classification, highlighting differences and pathogenic relationships.

Giant cell tumor of bone (GCTB) is a locally aggressive primary bone neoplasm composed by tumoral stromal cells (SCs) and a reactive component that consists of monocytic/histiocytic cells that give rise by fusion to osteoclast-like multinucleated cells. Recently, specific Histone 3.3 mutations have been demonstrated in SCs of GCTB. Many of the pathways related to bone proliferation and regulation depend on the primary cilium, a microtubule-based organelle that protrudes outside the cell and acts as a sensorial antenna. In the present work, we aimed to study the presence and role of primary cilia in GCTB. Ultrastructural, immunohistochemical, and immunofluorescence studies were performed in order to demonstrate, for the first time, that the primary cilium is located in spindle-shaped SCs of GCTB. Moreover, we showed Hedgehog (Hh) signaling pathway activation in these cells. Hence, primary cilia may play a relevant role in GCTB tumorogenesis through Hh signaling activation in SCs. RESEARCH HIGHLIGHTS: Transmission electron microscopy allows describing and differentiating cellular subpopulations in giant cell tumor of bone (GCTB). The primary cilium is present in some tumoral stromal cells of GCTB. Hedgehog signalling is activated in these cells.

Giant cell tumor of bone (GCTB) is a rare osteolytic intermediate bone tumor that harbors a pathogenic H3F3A gene mutation and exhibits characteristic histology. The standard curative treatment for GCTB is complete surgical resection, but it frequently results in local recurrence and, more rarely, metastasis. Therefore, effective multidisciplinary treatment is needed. Although patient-derived tumor cell lines are promising tools for preclinical and basic research, there are only four available cell lines for GCTB in public cell banks. Thus, the aim of this study was to establish a novel GCTB cell line. Using surgically resected tumor tissues from a patient with GCTB, we established a cell line named NCC-GCTB4-C1. The cells harbored the typical H3F3A gene mutation and exhibited constant proliferation and invasive capabilities. After characterizing NCC-GCTB4-C1 cell behaviors, we conducted high-throughput screening of 214 anti-tumor drugs and identified seven effective drugs. Comparing the results of high-throughput screening using NCC-GCTB4-C1 cell line with the results using NCC-GCTB1-C1, NCC-GCTB2-C1, and NCC-GCTB3-C1 cell lines that we previously established, four drugs were in common effective. This study showed potential drugs for the treatment of GCTB. These data indicate that NCC-GCTB4-C1 has the potential to be a powerful tool in preclinical and basic research on GCTB.

Background The cytopathology of a giant cell tumor of soft tissue (GCT-ST), a fibrohistiocytic neoplasm distinct from other giant cell-rich soft tissue tumors, is rarely reported. The authors report their experience with a series of 4 GCT-ST fine-needle aspiration (FNA) biopsy cases and compare them with a set from giant cell tumors of bone (GCTBs). Methods The authors' cytopathology files were searched for GCT-ST examples with histopathologic confirmation. FNA biopsy smears were performed and examined with standard techniques. Results Four cases of GCT-ST presenting as a primary soft tissue mass from 4 patients (3 males and 1 female; age range, 28-75 years, mean age, 53 years) were retrieved. FNA sites included the anterior tibia, buttock, shoulder, and upper back. Three cases were interpreted as suspicious for sarcoma radiographically. The specific diagnoses were atypical giant cell tumor of tendon sheath, suspicious for GCT-ST, atypical myxoid lesion with giant cells, and benign with osteoclast-like giant cells (OLGCs). No case was interpreted as malignant. Aspirates consisted of mononuclear polygonal cells, spindled fibroblast cell clusters, and large OLGCs to the near exclusion of other cell types. OLGCs possessed 10 or more nuclei per cell. A comparison with GCTB aspirates and single case reports from the literature showed comparable cytomorphology. Conclusions GCT-ST FNA smears mimic those of GCTBs containing a limited population of uniform spindle cell clusters, single dispersed polygonal cells, and cytologically banal OLGCs. GCT-ST should be considered in the differential diagnosis of aspirates containing numerous osteoclast-like giant cells.

Objective: To evaluate the prognostic significance of neutrophil-to-lymphocyte ratio (NLR) in giant cell tumor of bone (GCT). Methods: The patients with GCT were identified in the hospital records and pre-treatment complete blood count results were acquired retrospectively. Whether preoperative NLR lymphocyte-to-monocyte ratio (LMR) and platelet-to-lymphocyte ratio (PLR) values had prognostic significance in predicting recurrence was evaluated by Receiver operating curve (ROC) analysis. Furthermore, the prognostic value of NLR was evaluated by Multivariable Cox Regression analysis. Results: There were 96 patients with GCT. It was found that only NLR values had prognostic significance for predicting recurrence (AUC:0.647; 95% CI:0.533-0.762; P=0.021). The statistically significant cut-off value of NLR for predicting re- currence was ≥2.25.NLR was ≥2.25 in 51% (n = 49) of patients. Multivariable analysis showed that NLR ≥2.25 (HR=2.9, 95% CI:1.3-6.6; p=0.009) and lung metastasis (HR=7.9, 95% CI:2.2-28.2; p=0.001) were independent factors of recurrence. In patients with lung metastasis and patients with NLR ≥2.25, recurrence was observed in a sooner period (Log rank test; p=0.001; p=0.009, respectively). Conclusion: Our findings showed that NLR is a new and promising inflammation-based prognostic factor in GCT patients. Keywords: Giant cell tumor of bone; neutrophil-to-lymphocyte ratio; prognostic significance.

Giant cell tumor (GCT) of the bone is a locally aggressive and rarely metastasizing neoplasm. It is composed of neoplastic mononuclear stromal cells with a monotonous appearance admixed with macrophages and osteoclast-like giant cells. In a small subset of cases, GCT is malignant. Terminology previously related to this entity, and which is no longer supported by the World Health Organization, includes osteoclastoma and benign fibrous histiocytoma (BFH). Giant cells occur in numerous other pathologic conditions of the bone, which accounts for the misrepresentation of these non-GCT tumors in the early literature. Non-ossifying fibroma (NOF), aneurysmal bone cyst, and chondroblastoma have been erroneously labeled GCT for this reason. A single description of an ancient GCT was reported by Brothwell and Sandison and subsequently mentioned by Aufderheide and Rodrìguez-Martìn who were astonished that more of these tumors had not been identified in archaeological cases. To the best of our knowledge, no other cases of ancient GCT have been cited in the paleopathology literature. The study of this type of neoplasm in antiquity can be used as a means to better understand its characteristics and behavior and to expand the depth of time of the etiology of these lesions. We report a case of GCT of the left femur observed following the total body CT imaging of a partially mummified adult female, dating to eighteenth century.

Introduction Giant cell tumors of bone (GCTBs) are treated with surgery with or without local adjuvants. Denosumab is a human monoclonal antibody that has recently emerged to be effective in treating unresectable and recurrent GCTBs. Objective In this study, we analyzed the histomorphological changes in GCTB following treatment with denosumab. The expression of histone mutation H3.3G34W by immunohistochemistry (IHC) using mutant specific antibody was also determined. Materials and Methods Of the total 109 GCTBs encountered during the study period, 14 cases with neoadjuvant denosumab therapy were analyzed retrospectively. The post-treatment changes on histopathology were examined on routine hematoxylin and eosin-stained sections. IHC was done using antihistone H3.3G34 antibodies. Statistical analysis was limited to descriptive statistics. No hypothesis testing was performed. Results All these cases except three showed fibrosis with areas of hyalinization, prominent newly formed woven bone along with spindle cells in short fascicles and storiform pattern. There was complete absence and marked reduction in osteoclast-like giant cells in six and five patients, respectively. Only three patients showed a substantial amount of residual osteoclast-like giant cells. IHC with antihistone H3.3G34W antibody showed unequivocal nuclear positivity in the mononuclear cells in nine cases. The mononuclear cells rimming and entrapped within the woven bone were also positive on IHC. The spindle cells in the benign fibrous histiocytoma-like areas and septa of aneurysmal bone cyst-like areas also retained nuclear staining. Conclusion Awareness of post-denosumab-related histopathological changes are necessary to avoid misdiagnosis as fibroosseous lesion and low-grade central osteosarcoma. Expression of mutant-specific H3.3 G34W antibody suggests that the neoplastic stromal cells are largely retained after denosumab therapy. The positive staining of cells both within and those rimming the newly formed woven bone point toward osteoblastic phenotype of the neoplastic stromal cells.

Primary malignant giant cell tumor of bone is clinically rare, lack of specificity, and often misdiagnosed. Currently, related literature about this tumor remains scarce. One case of primary malignant giant cell tumor of bone was diagnosed and treated in our hospital, and the treatment effect was satisfactory. There was no recurrence or metastasis in 2 years of follow-up. The report is as follows.

Giant cell tumor of bone (GCTB) is a locally aggressive and rarely metastasizing tumor. GCTB is characterized by the presence of unique giant cells and a recurrent mutation in the histone tail of the histone variant H3.3, which is encoded by H3F3A on chromosome 1. GCTB accounts for ~ 5% of primary bone tumors. Although GCTB exhibits an indolent course, it has the potential to develop aggressive behaviors associated with local recurrence and distant metastasis. Currently, complete surgical resection is the only curative treatment, and novel therapeutic strategies are required. Patient-derived cancer cell lines are critical tools for basic and pre-clinical research. However, only a few GCTB cell lines have been reported, and none of them are available from public cell banks. Therefore, we aimed to establish novel GCTB cell lines in the present study. Using curetted tumor tissues of GCTB, we established two cell lines and named them NCC-GCTB2-C1 and NCC-GCTB3-C1. These cells harbored a typical mutation in histones and exhibited slow but constant growth, formed spheroids, and had invasive capabilities. We demonstrated the utility of these cell lines for high-throughput drug screening using 214 anticancer agents. We concluded that NCC-GCTB2-C1 and NCC-GCTB3-C1 cell lines were useful for the in vitro study of GCTB.

Involvement of toe phalanges by giant cell tumor (GCT) is extremely rare; tumors in these locations tend to be aggressive. Whereas aggressive GCTs of the distal phalanx may be managed successfully by en-bloc resection without reconstruction or amputation, management of these lesions, when they involve the proximal phalanx, can be challenging. We present a Campannaci grade III GCT of the hallucal proximal phalanx in a 14-year old girl that had breached into the dorsal soft tissues and the metatarso-phalangeal joint. Wide local resection of the proximal phalanx along with reconstruction arthrodesis with an autologous, non-vascularized fibular strut graft was performed. There was no recurrence at 3 years of follow-up. The patient had an excellent functional outcome. To the best of our knowledge, this is the first case reporting the outcomes of fibular strut arthrodesis for salvage of GCT of the hallucal proximal phalanx.

Objectives To describe the technique of the aorta balloon occlusion, and evaluate the blood loss in lumbar spine tumor surgery assisted by aortic balloon occlusion, and to observe the balloon‐related complications. Methods Six patients with lumbar spine tumor underwent resuscitative endovascular balloon occlusion of the aorta prior to tumor resections in our institution between May 2018 to January 2021. Medical records including demographic, diagnosis, tumor location, surgical approach, intraoperative blood loss, surgical duration, and perioperative balloon‐related complication were evaluated retrospectively. Results This series included four males and two females, with a median age of 50 years (range 22 to 69). Of these, three primary tumors were plasmacytoma, giant cell tumor of bone, and osteosarcoma, while recurrence of undifferentiated pleomorphic sarcoma (UPS), recurrence of giant cell tumor of bone (GCT), and metastatic thyroid cancer were diagnosed in cases 1, 6, and 2, respectively. L2 was involved in cases 1 and 5. L3 was involved in case 6. L4 was involved in case 2, 3, and 6. L5 was involved in case 4. One‐stage total en bloc resection surgery (TES) was accomplished in all patients; of this series, signal anterior approach was conducted in case 1, signal posterior approach was utilized in cases 2, 3, and 6, while combined anterior and posterior approach was performed in cases 4 and 5. The median intraoperative blood loss was 1683 mL and ranged from 400 to 3200 mL with a median surgical duration of 442 min and a range from 210 to 810 min. During the perioperative period, no serious balloon‐related complications occurred. Conclusions Endovascular balloon occlusion of the aorta successfully controls intraoperative exsanguination, contributing to a more radical tumor resection and a low rate of tumor cell contamination in lumbar tumor surgery., Schematic diagram of the patient with a tumor involved to level L4 had resuscitative endovascular balloon occlusion of the aorta intraoperatively. (i) The patient was transferred to the interventional radiology unit and placed in supine position. Abiding by the Seldinger technique, a balloon dilation catheter (BDC) was inserted to the designated location and then shifted to prone position. (ii) The expected position of the balloon was cephalad to abdominal aortic bifurcation but caudal to the renal arteries (zone III). After the balloon inflated, blood flow to the distal aorta was stopped during the subsequent tumor resection. (iii). During orthopaedic oncology procedure, occlusion of abdominal aorta was identified by the disappearance of dorsal pedis arteries and pulse oximeter oxygen saturation (SpO2) signals from toe.

Two‐dimensional (2D) culture of cells from giant cell tumor of bone (GCTB) is affected by loss of the multinucleated giant cells in subsequent passages. Therefore, there is limited time to study GCTB with all its histological components in 2D culture. Here, we explored the possibility of culturing GCTB cells on a polycaprolactone (PCL)‐printed scaffold. We also evaluated the viability of the cultured cells and their adherence to the PCL scaffold at day 14 days using immunofluorescence analysis with calcein, vinculin, and phalloidin. Using the histological technique with hematoxylin and eosin staining, we observed all the histological components of GCTB in this 3D model. Immunohistochemical assays with cathepsin K, p63, and receptor activator of nuclear factor (NF)‐κB ligand (RANKL) yielded positive results in this construct, which allowed us to confirm that the seeded cells maintained the expression of GCTB markers. Based on these findings, we concluded that the PCL scaffold is an efficient model to culture GCTB cells, and the cell viability and adherence to the scaffold can be preserved for up to 14 days. Moreover, this model can also be used in subsequent studies to assess in vitro cell–cell interactions and antineoplastic efficacy of certain agents to establish a treatment against GCTB.

Giant cell tumor of bone (GCTB) is a benign neoplasia more frequently encountered in young females. The pathogenic and evolutionary dynamics of the disease is strongly influenced by the presence of depression and cellular mechanisms, especially proinflammatory and immune. Although it is not a malignant tumor, it is often recurrent, which determines a high level of depression, anxiety, and fear of the patients. Cytokine mechanisms, especially through increased tumor necrosis factor alpha (TNFα) and interleukin-6 (IL-6), as well as the involvement of the receptor activator of nuclear factor-kappa B (RANK)–RANK ligand (RANK-L) system, can be correlated with the risk of malignancy. Unfavorable evolution is associated with persistent pain, difficulties of movement and body dysmorphic symptoms. The diagnosis is based mainly on histopathological (HP) assessment. The patients can be treated with pharmacological agents (Denosumab), surgery with tumor excision, reconstruction or osteosynthesis, and radiotherapy. Patients with GCTB require HP and imaging evaluations, especially of relapses, to detect the risk of metastasis or malignancy, simultaneously with psychological and psychiatric monitoring to detect depression, addictive behaviors, and suicide risk. It is necessary to evaluate in a multidisciplinary team to avoid unfavorable oncological and psychiatric developments. Through its clinical, HP, and therapeutic features, GCTB has multiple connections with the psychological and psychopathological dimension.

Giant cell tumor of bone (GCTB) is a rare, benign, but locally aggressive bone tumor. It has a high tendency for local recurrence, which may increase the incidence of lung metastasis. Currently, an optimal treatment strategy has not been established because of the rarity of pulmonary metastatic GCTB. Denosumab is the preferred regimen for unresectable metastatic lesions; however, there are no alternative treatment options when patients are resistant to denosumab. Apatinib is a small-molecule tyrosine kinase inhibitor that selectively competes for the vascular endothelial growth factor receptor 2 (VEGFR-2) ATP binding site, and several studies have analyzed the effectiveness of apatinib in advanced or metastatic tumors. However, there is no report of apatinib as an anti-angiogenesis therapy for pulmonary metastatic GCTB to date. Here, we present a case of a 26-year-old female who was diagnosed with recurrent and pulmonary metastatic GCTB. Immunohistochemical (IHC) staining indicated that the tumor cells were positive for VEGFR-2. Denosumab was administered to control the metastases; nevertheless, disease progression was confirmed after four months of treatment. Given the IHC results and rapid disease progression, apatinib was added to the treatment strategy. After 42 months of treatment, the patient showed noticeable symptomatic improvement and considerable tumor shrinkage.

Giant cell tumors (GCT) of bone are a benign aggressive tumor with features of frequent local recurrence. It has the potential for metastasis and malignant transformation. GCT of bone represents about 4–9.5% of primary bone tumors. Metachronous GCT happen in less than 1% while metastatic spread in these lesions is very uncommon. Furthermore, reports of multicentric metachronous GCT are very rare in literature. We present a case of a 35-year-old male patient, who suffered from multicentric metachronous GCT, which involved the radius, humerus, femur, and pelvic with pulmonary metastasis. Local control by multiple resections of the tumor and chemotherapy for pulmonary metastases was able to control the disease with long-term survival and good functional outcome. These tumors had a typical radiological appearance and the diagnosis was confirmed on histopathology. Long follow-up needed in this case in view the illness occurs for long period.

Background . Giant cell tumor of bone (GCTB) is a common benign lesion accounting for 4–9.5 % of all primary bone tumors. Although surgery is considered the method of choice in the treatment of GCT, however, denosumab, a genetically engineered drug with a novel mechanism of action, has been recently used to treat GCTB. Histological examination of a surgical specimen is undoubtedly the most objective method for assessing the effectiveness of the treatment. However, in some cases it is necessary to assess the effectiveness of conservative therapy at the stages of its implementation. The purpose of the study was to compare CT-densitometry findings with histological findings in GCTB patients treated with denosumab. Material and Methods. The study included 30 patients aged from 28 to 59 years with histologically verified GCTB, who received targeted therapy with denosumab followed by surgery. The changes in tumor structure during denosumab therapy and surgical specimens of the tumor were assessed. Results. The relationship between the CT-densitometry findings and histopathological findings of surgical specimens was revealed in GCTB patients treated with denosumab. Conclusion. CT-densitometry findings were shown can be used to predict pathological response of the tumor to denosumab treatment.

BACKGROUND Giant cell tumor (GCT) is a benign lesion and rarely involves the patella. This disease is characterized by a relatively high recurrence rate after primary treatment. En bloc resection has been a predominant option for recurrent GCT. However, total patellectomy can lead to disruption of the knee. Therefore, exploration of functional reconstruction of the extensor mechanism is worthwhile. CASE SUMMARY A 54-year-old woman presented with right knee pain and swelling, and was diagnosed as having a GCT in the patella following curettage and autograft. Medical imaging revealed a lytic and expanded lesion involving the whole patella with focal cortical breaches and pathological fracture. Based on the combination of histological, radiological, and clinical features, a diagnosis of recurrent GCT in the patella was made (Campanacci grade III). After a multidisciplinary team discussion, three-dimensional (3D)-printed custom-made patellar endoprosthesis was performed following en bloc resection for reconstructing the extensor mechanism. The patient was followed for 35 mo postoperatively. No evidence of local recurrence, pulmonary metastasis, or osteoarthritis of the right knee was observed. The active flexion arc was 0°-120°, and no extension lag was detected. A favorable patellar tracking and height (Insall-Salvati ratio 0.93) were detected by radiography. CONCLUSION We depict a case of a GCT at the right patella, which was successfully treated by patellectomy and 3D-printed custom-made endoprosthetic replacement. The patella normal reconstruction, the precise-fit articular design, and gastrocnemius flap augmentation could lead to satisfactory knee function and a low rate of complications in the short-term follow-up.

We will provide an imaging-focused discussion of 3 benign bone tumors that do not fit in the categories of cartilaginous tumors or osteoid tumors. We have chosen giant cell tumor of bone, unicameral bone cyst, and fibrous dysplasia. All 3 of these entities are common enough that one does not have to be a musculoskeletal radiologist in a cancer hospital to encounter them occasionally, but none of them should be seen frequently.

BACKGROUND: Giant cell tumor of bone (GC), osteosarcoma (OS) and Ewing’s sarcoma (ES) are three different types of bone cancer with common and specific pathology features. OBJECTIVE: The purpose of the study was to examine the relationship and differences of the three bone tumors using clinical samples. METHODS: Through screening the profiles of clinical samples from GC, OS and ES patients using a humanoncology array, we found 26, 25 and 15 tumorigenesis factors significantly increased in GS, OS and ES tissues compared to normal individuals. eNOS, endostatin, HIF-1α, IL-6, CCL2/MCP-1, CCL8/MCP-2, CCL7/MCP-3, Tie and VEGF directly or indirectly involve in the metastasis Therefore, expression levels of the 6 factors were further determined by Western blot. RESULTS: The results showed levels of MCP1, MCP2, MCP3 or IL-6 in the GS, OS and ES significantly increased, and the expression levels of angiogenesis and anti-angiogenesis factors containing eNOS, endostatin, HIF-1α, Tie or VEGF were enhanced. CONCLUSIONS: Our results suggest that eNOS, endostatin, HIF-1α, IL-6, CCL2/MCP-1, CCL8/MCP-2, CCL7/MCP-3, Tie and VEGF may play important roles in tumorigenesis, reveal the expression differences of tumor-associated cytokines and angiogenesis related factors, and provide clinical evidence for studying the mechanisms on the metastasis in GC, OS and ES.

Denosumab is an established targeted systemic therapy for treatment of giant cell tumor of bone (GCTB). We sought to determine whether treatment response could be quantified from radiomics analysis of radiographs taken longitudinally during treatment. Pre- and post-treatment radiographs of 10 GCTB tumors from 10 patients demonstrating histologic response after treatment with denosumab were analyzed. Intensity- and texture-based radiomics features for each manually segmented tumor were calculated. Radiomics features were compared pre- and post-treatment in tumors. Mean intensity (p = 0.033) significantly increased while skewness (p = 0.028) significantly decreased after treatment. Post-treatment increases in fractal dimensions (p = 0.057) and abundance (p = 0.065) approached significance. A potential linear correlation in mean (p = 0.005; ΔMean = 0.022 * duration − 0.026) with treatment duration was observed. Radiomics analysis of plain radiographs quantifies time-dependent matrix mineralization and trabecular reconstitution that mark positive response of giant cell tumors of bone to denosumab.

BACKGROUND AND OBJECTIVES Benign bone tumors are often treated with extended curettage utilizing an adjuvant therapy to eliminate any remaining tumor cells. The purpose of this study was to explore and compare the histologic depth of necrosis created by various adjuvant therapies used in the treatment of benign bone tumors. METHODS A high-speed burr was utilized to create cortical defects within porcine humeri and femora. Phenol, polymethyl methacrylate (PMMA), argon beam coagulation (ABC), liquid nitrogen, and the Bipolar Hemostatic Sealer (BHS) were each applied to five defects, with an additional five defects left untreated as a control. The maximal depth of necrosis was determined under microscopic examination. RESULTS The phenol, PMMA, ABC, liquid nitrogen, and BHS demonstrated an average histologic depth of necrosis of 0.30, 0.78, 2.54, 2.54, and 0.92 mm, respectively, each of which was significantly increased compared to the control group (p = .001, .003, .003, .01, and

Highlights • Giant cell tumor (GCT) especially in distal ulna is a rare and benign neoplasm, but locally invasive tumor. • En-bloc resection combined with extensor carpi ulnaris and flexor carpi ulnaris stabilization was performed to excise GCT of distal ulna. • This procedure gives full restoration of forearm function without any limitation and produces excellent DASH score., Introduction Giant Cell Tumor (GCT) is a form of bone tumor which is rare, benign, and locally invasive. To date, there have not been many case reports regarding cases of GCTs on the distal ulna which made the optimum strategy in management remain controversial. In some reported cases, the patient was treated with wide excision followed by reconstructive procedure resulting in ulnar translation of the carpal bones and dynamic convergence of the ulna towards the radius. Presentation of case We documented a case of 29-year-old male with distal ulna GCT, treated with en-bloc resection combined with extensor carpi ulnaris and flexor carpi ulnaris tendon stabilization. The key objectives of GCT treatments are to avoid local recurrence with sufficient resection and to maintain the function of the limbs. Specific treatment options have been suggested for en-bloc resection with or without the need for ulnar reconstruction or stabilization, even prothesis. In this case, we excised the distal portion of the ulna with some soft tissue procedure for added stability. Clinical discussion Three weeks after the surgery, the patient was able to perform wrist flexion and extension, fingers abduction, adduction, and opposition with slight limitation. The DASH and PRWE score had improved gradually within 3 weeks and 6 months after the surgery. Conclusion In the subsequent evaluation after six months of the surgery, the patient achieved full restoration of forearm function without any limitation.

Background The purpose of this study is to analyze the overall prognosis of giant cell tumor of bone (GCTB) and the risk factors that affect its postoperative recurrence. Methods The databases of PubMed, Cochrane, Web of Science, Embase, China national knowledge infrastructure, China Biology Medicine disc, and Wanfang were searched until 20 June 2020. Following patients, intervention, comparator, outcomes, study design (PICOS) guidelines, eligible articles were defined as studies evaluating the overall prognosis of GCTB and the risk factors that affect its postoperative recurrence. The association between five risk factors (surgical methods, whether there is soft tissue invasion, tumor size, p53 expression, vascular endothelial growth factor (VEGF) expression) and the recurrence of GCTB were calculated using fixed-effects or random-effects models. The heterogeneity of the odd ration (OR) and effect size (ES) of each study was quantified using Cochran’s Q test and Higgins-I2 statistic. The publication bias was analyzed through the drawing of the funnel diagram. Results A total of 10 studies were included in the study. We found that the probability of recurrence of patients who choose simple curettage is 5.75 times that of patients who choose amputation or total resection. Patients with soft tissue invasion are 3.76 times more likely to relapse than non-invasive GCTB. The probability of recurrence of patients with tumors larger than 5 cm is 2.8 times that of patients with tumors smaller than. Patients with positive expression of p53 are 3.82 times more likely to relapse than patients with negative expression. And patients with positive expression of VEGF are 3.82 times more likely to relapse than patients with negative expression. Conclusions In conclusion, our analysis of five risk factors can be used to measure the recurrence of GCTB and provide important preoperative recommendations for patients with GCTB.

Objective: This systematic review and meta-analysis aimed to determine the effect of preoperative denosumab on the local recurrence of giant-cell tumor of bone (GCTB) treated with curettage. Methods: PubMed, Embase, Cochrane Library, and Web of Science were comprehensively searched. The following data were analyzed using meta-analysis: local recurrence rate of patients receiving denosumab followed by curettage (denosumab group), local recurrence rate of patients receiving curettage only (control group), and a comparison of the local recurrence rates of the two groups. Results: Nine studies that contained 672 patients with GCTB were included in this review. Patients in the denosumab group (preoperative denosumab followed by curettage) had a higher risk of local recurrence compared with those in the control group (curettage only) (odds ratio = 3.04, 95% confidence interval = 1.48-6.22, P < 0.01). The association between preoperative denosumab and local recurrence remained significant in most of the subgroup analyses, except for those with sample sizes < 59 (P = 0.09), sacral GCTB (P = 0.42), and usage of postoperative denosumab (P = 0.38). Conclusions: Preoperative denosumab may increase the risk of local recurrence of GCTB treated with curettage and should be used with caution in the management of GCTB.

Background: Giant cell tumor of the bone (GCTB) occurs most often in younger individuals aged between 20 and 40 years. However, it also occurs in a small proportion of elderly people. Therefore, it is necessary to determine the clinical characteristics of GCTB in elderly people, as only few reports have completely examined the characteristics of GCTB in elderly patients. Methods: This retrospective study enrolled 69 patients with benign GCTB. Patients’ information on age, sex, anatomical location and size, Campanacci grade, pathological fracture, treatment for primary tumors, local and distant relapse, and outcome was collected. We compared these clinical courses between the younger and older groups. We divided the age groups into three subgroups: ≤54 years and ≥55 years, ≤59 years and ≥60 years, and ≤64 years and ≥65 years. We compared the two groups in each subgroup. In addition, we examined factors affecting local recurrence and distant metastasis. Results: Tumor size was significantly larger in the older group between the two subgroups of 55 and 60 years. Kaplan-Meier curves for local recurrence-free survival and distant metastasis-free survival between the two subgroups of 65 years showed significant differences (p = 0.0183 and p = 0.0014). In the multivariate logistic regression analyses, female sex, curettage-only surgical procedure, and denosumab usage before surgery affected local recurrence. Conclusion: Age is unlikely to affect local recurrence and distant metastases in GCTB patients, but local recurrence and distant metastases may be noted in elderly patients aged ≥65 years with GCTB.

Objective Giant cell tumors (GCTs) constitute 5% of all primary bone tumors with spinal GCTs (SGCTs) accounting for 2%–15% of all GCTs. The standard of care for SGCT has been maximal surgical resection. However, many adjuvant therapies have been used owing to the difficulty in achieving gross total resection combined with the high local recurrence rate. The purpose of the present study was to analyze the incidence, management, and outcomes of SGCT. Methods Patients with diagnosis codes specific for SGCT were queried from the National Cancer Database from 2004 to 2016. The outcomes were investigated using Cox univariate and multivariate regression analyses, and survival curves were generated for comparative visualization. Results The search criteria identified 92 patients in the NCDB dataset from 2004 to 2016 with a diagnosis of SGCT. Of the 92 patients, 64.1% had undergone surgical intervention, 24.8% had received radiotherapy, and 15.2% had received immunotherapy. Univariate analysis revealed that age ≥55 years and tumor location in the sacrum/coccyx were associated with worsened overall survival (OS) and that surgical resection was associated with improved OS. On multivariate analysis, age 55–64 years was associated with worsened OS, and radical surgical resection was associated with improved OS. The survival analysis revealed improved OS with surgery but not with radiotherapy, chemotherapy, or immunotherapy. Conclusion SGCT is a rare primary bone tumor of the vertebral column. The standard of care has been surgical resection with the goal of gross total resection; however, adjuvant therapies have often been used. Our study found that surgical resection significantly improved OS and that immunotherapy neared significance in improving OS.

Purpose of the study . To evaluate the effectiveness and possibility of wide clinical use of denosumab in neoadjuvant mode in patients with giant-cell bone tumors to simplify the operation by reducing the size of the tumor, consolidating pathological fractures, improving the quality of life, restoring the function of adjacent joints, by conducting 2 courses of denosumab as neoadjuvant targeted therapy for patients with giant-cell bone tumors, as well as evaluating morphological changes in tumor. Materials and methods . Considering the data on the efficacy of denosumab, all 10 patients underwent 2 courses of Denosumab 120 mg subcutaneously 1 time per month, as a neoadjuvant targeted therapy for a giant cell bone before performing a surgical treatment. The morphological picture was analyzed before and after the start of treatment, and the clinical and radiological results were evaluated. Results. A similar clinical picture was observed in all 10 cases involving pain relief and restoration of support ability of the bone. X-ray changes demonstrated the development of sclerotic processes in the foci of lytic destruction. Consolidation of pathological fractures was observed. The main changes determining the clinical and radiological characteristics were associated with the morphological processes occurring in the tumor under the influence of denosumab. The morphological picture in the surgically removed bone samples was associated with the development of fibroscle-rotic processes leading to the consolidation of pathological fractures. The histological changes were assessed at the light-optical level. Tumor cells (osteoblasts and osteoclasts) were replaced with fibrous tissue of varying maturity. That is, a response to the therapy (pathomorphosis in the tumor) was observed under the action of denosumab. Conclusions. Denosumab in neoadjuvant targeted therapy for patients with giant cell bone tumors prior to surgical treatment allows reduction in tumor sizes and consolidation of pathological fractures. The functions of adjacent joints were restored during Denosumab treatment. Improvements in the quality of life of patients were registered. The clinical and radiological effect of the therapy corresponded to the morphological changes occurring in the tumor. All of the above made it easier to perform surgery.

Objective The aim of this study was to present the mid-term functional outcomes and recurrence rate in patients with giant cell tumor of bone (GCTB) treated by intralesional extended curettage, electrocauterization, and polymethylmethacrylate (PMMA) cementation. Methods In this retrospective observational study, 79 consecutive patients (41 females, 38 males; mean age=39 years; age range=19-62 years) who were diagnosed and treated for GCTB between 2005 and 2017 were identified from hospital medical records. All patients were treated by intralesional extended curettage using high-speed burr, electrocauterization of the cavity, and filling the defect with PMMA. No additional local adjuvants were used. The mean follow-up period was 47 months (range=24-96). The tumors were graded according to the radiological classification system described by Campanacci. Functional outcomes were evaluated using the Musculoskeletal Tumor Society Score (MSTS) preoperatively, one year postoperatively, and at the final follow-up. Postoperative complications and recurrence rates were recorded. Results Twenty-nine tumors were located in the distal femur, 23 in the proximal tibia, nine in the distal radius, five in the proximal humerus, five in the pelvis, three in the proximal fibula, two in the distal ulna, two in the distal tibia, and one in the second metatarsal. According to Campanacci classification, 37 tumors were grade III, 32 grade II, and 10 grade I. The mean MSTS score was 46.1% (range 40.2 to 71.4%) preoperatively, 91.7% (range 73.3% to 100%) one year postoperatively, and 86.3 % (range 66.2% to 96,1%) at the final follow-up. The overall complication rate was 7.6%; which included local tumor recurrence in four patients, superficial wound infection in one, and deep wound infection in another. The recurrence rate was 5.1% (4 patients). Recurrent tumors were located at the distal femur in three patients and proximal tibia in one. Conclusion With satisfactory functional results and low recurrence rates at the mid-term follow-up, GCTB can be treated effectively with intralesional extended curettage, electrocauterization, and PMMA cementation. Level of evidence Level IV, Therapeutic study.

We describe a rare pediatric case of a phalangeal giant cell tumor of bone with extensive bilateral lung metastases following curettage, wide resection, and amputation. Concurrent peripheral blood eosinophilia and pleural effusion with marked eosinophilia (47%) were present. To discover genetic changes driving tumor metastasis, genomic and transcriptome profiling of the metastatic lung mass as well as germline analysis were performed. Whole exome sequencing detected a histone H3F3A p.G35V missense mutation in tumor cells. RNA sequencing revealed overexpression of receptor activator of nuclear factor kappa-B ligand (RANKL). The patient is alive with no residual disease and uncompromised respiratory function 29 months after amputation of primary tumor and 19 months after surgical resection of his metastatic lung disease.

We report a case of GCTB in an 84-year-old Japanese man who had a tumor in his left iliac bone and was treated safely with denosumab. The patient noticed a painful mass, with gradual enlargement, in his left low back next to the iliac region. Magnetic resonance imaging revealed that the tumor measured 94 × 66 × 90 mm and was located in the left iliac bone. Histologically, the tumor was composed of proliferative oval-shaped mononuclear cells, admixed with large number of osteoclast-like giant cells. Immunohistochemically, a strong positivity for histone 3.3 G34W mutant protein was observed in the nuclei of the mononuclear cells, confirming the diagnosis of GCTB. Because it was considered as unresectable tumor, the patient was treated with denosumab without any side effects.

Giant cell tumor of bone (GCTB) is a rare osteolytic bone tumor, accounting for approximately 5% of all primary bone tumors. GCTB is characterized by unique giant cells. It is also characterized by recurrent mutations in the histone tail of the histone variant H3.3, H3F3A, on chromosome 1, therapeutic implications of which have not been established yet. There are few effective standardized treatments for GCTB, and a novel therapy has long been required. Patient-derived cancer cells have facilitated the understanding of mechanisms underlying the etiology and progression of multiple cancers. Thus far, only 10 GCTB cell lines have been reported, and none of them are publicly available. The aim of this study was to develop an accessible patient-derived cell line of GCTB, which could be used as a screening tool for drug development. Here, we describe the establishment of a cell line, designated NCC-GCTB1-C1, from the primary tumor tissue of a male patient with GCTB on the right distal radius. NCC-GCTB1-C1 cells were maintained as a monolayer culture for over 23 passages for 7 months. These cells exhibited continuous growth, as well as spheroid formation and invasive ability. Using an oncology agent screen, we tested the effect of anticancer drugs on the proliferation of NCC-GCTB1-C1 cells. The cells displayed a remarkable response to romidepsin and vincristine. Thus, we established a novel GCTB cell line, NCC-GCTB1-C1, which could be a useful tool for studying GCTB tumorigenesis and the efficacy of anticancer drugs.

Giant cell tumor of bone is a locally aggressive, rarely metastasizing neoplasm. Evidence suggests that the neoplastic cells may be osteoblastic in differentiation. Standard treatment is surgical removal, but medical therapy with denosumab, an inhibitor of receptor activator of nuclear factor-κβ ligand, has become a component of patient management in select cases. Denosumab-treated giant cell tumor of bone (DT-GCTB) shows drastic morphologic changes including the presence of abundant bone. To further determine the relationship of the neoplastic cells to osteoblast phenotype, we performed a morphologic and immunohistochemical study on a series of DT-GCTB. Cases of DT-GCTB were retrieved from surgical pathology files, available slides were reviewed, and immunohistochemistry for H3.3 G34W, SATB2, and p63 was performed. The cohort included 31 tumors from 30 patients (2:3 male:female), ages 15 to 73 years (median=36 y). The morphology of post-denosumab-treated tumors ranged from tumors composed of an abundant bone matrix with few spindle cells to spindle cell-predominant tumors. Five had focal residual classic CGTB, and 2 manifested mild nuclear atypia. The majority expressed all markers: 86.2% for H3.3 G34W, 96.7% for SATB2, and 100% for p63. All markers stained the various tumor components including spindle cells and the cells on the surface of and within the treated tumor bone matrix. Most markers were also positive in reactive-appearing woven bone adjacent to tumor: 84.6% for H3.3 G34W, 100% for SATB2, and 68% for p63. These findings suggest that denosumab treatment of giant cell tumor of bone results in osteoblastic differentiation with bone production.

Background Giant cell tumour of bone (GCTOB) is a relatively uncommon, benign, but locally aggressive neoplasm. Denosumab is a fully human monoclonal antibody with inhibitory effects on receptor activator of nuclear factor kappa-B ligand that has shown early promise as a possible treatment adjuvant for GCTB. However, much is still unknown about its current indications, long-term effects, the potential risk for rapid relapse and its involvement in sarcomatous transformation. Methods We analysed the outcomes of 154 patients with GCTOB. We assessed clinical outcomes via local recurrence free-survival, metastatic free-survival and sarcomatous transformation between those treated without Denosumab and those with neo-adjuvant Denosumab. Our radiological and pathological outcomes were assessed through independent specialist reviews. Results Four (19.0%) patients of the neo-adjuvant group had local recurrence of disease versus 16 (12.0%) patients in the surgery alone group; this results in a 3.62 times increased likelihood of developing local recurrence (P = 0.030). The median time to local recurrence was shorter for the neo-adjuvant group (421.5 days versus 788.5 days) (P = 0.01). There was no difference between Denosumab and the surgery groups in terms of metastatic disease (P = 0.45). Two patients in our cohort with GCTOB developed sarcomatous transformation, both were treated with Denosumab. Conclusion Our use of Denosumab tended to be for those patients who had surgically difficult tumours to halt the progression and allow easier resections. Of concern we noted a trend towards increasing recurrence rates with the potential risk for rapid relapse. Furthermore, two cases experienced sarcomatous transformation, which is a growing area of concern within the literature.

Giant cell tumor of bone (GCTB) is potentially malignant with a high risk of recurrence. Conventional GCTB diagnosis is often empirical based on histopathology with low efficiency. Reliable auxiliary diagnosis system can improve the efficiency, but it need accurate GCTB detection. Changes of micro-structure of GCTB tissue can alter the scattering properties that lead to the variation of the polarization state of GCTB tissue. This paper proposed a GCTB detection method by using Mueller matrix polarization microscopic (MMPM) imaging and multi-parameters fusion network. First, a MMPM image dataset of GCTB tissue is set up, and based on this dataset the effectiveness of MMPM imaging in the GCTB detection is verified for the first time. Then a multi-parameters fusion network(MPFN) model is proposed to fuse the deep features and hand craft features, which leverages the advantages of both hand-crafted features and deep learning based systems. Experiment results show that the MPFN outperformed state-of-the-art for GCTB lesions detection.

Highlights • The distal Ulna is an unusual site (0.45%–3.2%) for a primary bone GCT. • The functional reconstruction of the defect after resection has been a challenge. • Many surgeons try to retain the ulna and perform the only curettage and packing with polymethylmethacrylate. Unfortunately, there is a high recurrence rate of up to 40% when treated in such a manner. • Wide resection of the distal ulna with or without reconstruction or stabilization of the ulnar stump is the recommended treatment for GCTs in such locations. • We present two patients with GCT of the distal ulna, all of them treated by wide resection of the distal ulna followed by stabilization of the remaining ulna using one half of the extensor carpi ulnaris (ECU) tendon. All the patient satisfied with the treatment., Introduction Giant-cell tumor (GCT) of bone occurred in the distal end of the ulna is extremely uncommon. Wide resection is usually indicated in such cases and at times it may be necessary to remove a long segment of the distal ulna. The functional reconstruction of the defect after resection has been a challenge. Wide resection of the distal ulna with or without reconstruction or stabilization of the ulnar stump is the recommended treatment for GCTs in such locations. Presentation of case There were 2 cases of giant cells tumor of the distal ulna. They treated with wide resection and stabilization of ulnar stump by extensor carpi ulnaris tendon. We were evaluating outcomes using the Musculoskeletal Tumor Society (MSTS) Score for the upper extremity. The results from the evaluation of the MSTS Score were an average of 24 points. Discussion There were 2 patients. All of them present with lumps of their wrist and the pain over the lump. Patients treated with wide resection and stabilization of ulnar stump by extensor carpi ulnaris. The result from the evaluation of the Musculoskeletal Tumor Society (MSTS) score were 24 points. Conclusion Giant cell tumor of bone is a rare, generally benign, locally invasive tumor. The ulna distal extremity is an unusual site for a primary bone GCT. Any ulnar resection proximal to the insertion of the pronator quadratus can lead to instability in the form of radio-ulnar convergence and dorsal displacement (winging) of the ulnar stump. This can result in a diminution of forearm rotation and weakness with grasp. The main goal of stabilization is the stable, pain-free, and functional outcome of the wrist. In this cases report our patient with giant cell tumor were treated with wide resection and stabilization of ulnar stump by extensor carpi ulnaris. All of the patients satisfied with our treatment.

Background Multiple primary tumors, especially quadruple primary neoplasms is extremely rare. Fibrous dysplasia (FD), osteosarcoma (OS), and giant cell tumor of bone (GCTB) are three bone tumors with low incidence while primary pulmonary meningioma is a rare disease. In this case report, we present a unique synchronous occurrence of these four separate pathological conditions. Case presentation A 53-year-old male previously underwent resection of OS of fifth rib and FD of eighth rib 1 year ago. Recently, a discontinuous pain at right knee developed. Serial X-ray films showed a progressively pure osteolytic lesion of proximal tibia which extended gradually. The incisional biopsy revealed that this tumor was confirmed as GCTB, and the tumor was successfully managed by extensive curettage and bone cement filling. The diagnosis of GCTB was re-confirmed by the postoperative histopathologic examinations. High-throughput sequencing from the GCTB exhibited a somatic mutation of H3.3A (G35W exon2). Germline testing revealed a germ-cell variant in gene of BRCA2 (exon 8 V220Ifs*4). Conclusions This is a unique case with quadruple primary tumors. Germline mutation in gene of BRCA2 may be associated with the occurrence of multiple primary tumors in this patient.

Context. Denosumab is a monoclonal antibody against RANK ligand. Its administration in giant cell tumor of bone (GCTB) cases results in elimination of giant cells and new bone formation. Neoplastic stromal cells of GCTB harbor mutation of histone 3.3 and have pre-osteoblastic properties and thus express SATB2. Objectives. To (1) analyze histological changes in post-denosumab–treated GCTB, (2) analyze expression of H3.3G34W and SATB2 in pre- and post-denosumab–treated samples, and (3) to discuss why changes occur in the expression of not only H3.3G34W but also SATB2. Materials and Methods. Hematoxylin and eosin slides of 19 cases of denosumab-treated GCTB were reviewed. Immunohistochemical stains H3.3G34W and SATB2 were performed. The number of positive mononuclear cells were counted and graded. Results. Complete absence of osteoclast-like giant cells (OCLGCs) was noted in most cases along with a fibro-osseous component merging with peripheral shell of reactive bone. Irregular trabeculae of woven bone and osteoid with focal osteoblastic rimming was seen. Spindle cells were arranged predominantly in fascicular pattern. Morphometric analysis of H3.3G34W showed a mean of 68.8% positive stromal cells in pretreatment and a mean of 26.9% positive stromal cells in posttreated specimens with a statistically significant P value (.001). Mean percentage of SATB2-positive stromal cells in the pre- and posttreatment specimens was 36.46% and 20.8%, respectively. Conclusions. Our study validates that denosumab treatment results in marked reduction of OCLGCs with increased osteoblastic activity. Decreased expression of H3.3G34W in posttreatment may be a result of decreased antigenicity of neoplastic mononuclear cells. No significant change in SATB2 expression was noted.

Background Giant cell tumor of bone (GCTB) is considered to be a kind of borderline tumor, which has a tendency to recur and translocate. MicroRNAs are one type of small noncoding RNA, which can inhibit the translation of targeted mRNA through RNA‐induced silencing complex. Methods Microarray was conducted on three groups of tumor tissues and normal tissues from patients with GCTB, and results showed different expression profiles of miRNAs with Gene Ontology analysis and Kyoto Encyclopedia of Genes and Genomes analysis. The functions of miR‐187‐5p and miR‐1323, which were highly expressed in GCTB, were examined by 5‐ethynyl‐2′‐deoxyuridine (EDU), transwell, and CCK8 assays. RNAhybrid et al. (rna prediction softwares) predicted that the two microRNAs targeted fibroblast growth factor receptor substrate 2 (FRS2), which was verified by luciferase assay and rescue experiments. Results miR‐187‐5p and miR‐1323 were highly expressed in tumor tissues. They can jointly regulate the biological functions of GCTB in vitro. Luciferase assay confirmed that the two microRNAs can bind to the 3′ untranslated regions (UTR) of mRNA of FRS2. And, rescue experiments verified the relationships between the two microRNAs and FRS2. Conclusion There were some different‐expressed microRNAs between GCTB and normal tissues. miR‐187‐5p and miR‐1323 can regulate the biological functions of GCTB through influencing the expression of FRS2., Our team had performed the microarrays on three groups of giant cell tumors of bone. And we found some aberrant expression of microRNAs, including miR‐187‐5p and miR‐1323. Then, we examined the two miRNAs' effects on giant cell tumor of bone.