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Central nervous system (CNS) germ cell tumors (GCT) have not been epidemiologically well described. Our study describes 2 population-based series of nonpineal CNS GCT. Data on all primary (malignant and nonmalignant) CNS (ICD-O-3 sites: C70.0–C72.9, C75.1–C75.3) GCT diagnosed between 2000 and 2004 from the Central Brain Tumor Registry of the United States (CBTRUS) and on all malignant GCT diagnosed between 1992 and 2005 from the Surveillance, Epidemiology, and End Results (SEER) were analyzed. Of 234 nonpineal GCT in CBTRUS, the most common site was brain, NOS (31.6%). Males had a greater frequency (59.7%) than females (40.3%). However, by age group, the male-to-female incidence rate ratio (IRR) differed: children (0–14 years) had an IRR of 1.1, young adults (15–29 years) an IRR of 2.3, and adults (aged 30+) an IRR of 1.0. For children and young adults, most tumors were malignant (86.8% and 89.0%, respectively), whereas for adults, more than half were nonmalignant (56.8%). Germinoma was the most frequent diagnosis (61.5%). In SEER, the frequency of malignant GCT in the CNS (2.5%) was greater than that in the mediastinum (2.1%). Of 408 malignant CNS GCT, 216 (52.9%) were nonpineal. The male-to-female IRR was 1.5. Overall relative survival for nonpineal CNS malignant GCT was 85.3% at 2 years, 77.3% at 5 years, and 67.6% at 10 years. Previous studies of GCT that have not stratified by site have suggested greater gender disparity. Nonpineal CNS GCT show no significant gender preference, yet have outcomes similar to pineal GCT.

Giant cell tumour of bone (GCT) is a relatively rare benign bone tumour more frequent in young people (20–40 years). Histologically, two cell types are represented, stromal cells of osteoblastic origin and a distinctive osteoclast-like population probably of monocytic origin. GCTs can be aggressive and they recur locally in up to 50% of cases; up to 5% of GCTs metastasise to the lungs and spontaneous transformation to a high-grade malignancy occurs in 1–3% of patients. The aetiology of GCT is not known, and no risk factors have been recognised, although familial clustering of both Paget’s disease and GCT has been reported.

GCTs account for approximately 3–5% of primary bone tumours. GCT is rarely multicentric and usually occurs at the epiphyses of long bones, but may also affect other bones.

There are few randomised, prospective clinical trials available to guide clinical management of GCT. Recent developments have led to evaluation of newer therapeutic agents, including biphosphonates and denosumab, with encouraging results. We report the case of a 66-year-old woman affected by GCT. In 1985 the patient, then 41 years old, presented a cystic lesion on her left tibia, which was removed surgically. This lesion relapsed two years later. Therefore the patient was hospitalised and received a diagnosis of “multicentric giant cell bone lesions” (limb-girdle, sternum, mandible, ribs), confirmed by histological examination. These lesions showed hyperactivity on bone scintigraphy. Plain radiographs demonstrated destructive lytic lesions. Blood and urinary examinations showed markedly elevated levels of bone alkaline phosphatase and urine pyridinoline and there was persistent bone pain. In 1993 normocalcaemic primary hyperparathyroidism was diagnosed and an adenoma was removed, with no relapse of the disease. Subsequently the patient started clodronate therapy, i.v., followed by alendronate-neridronate per os and clodronate i.m. for about nine years. Biphosphonate therapy caused a modest and transient decrease in bone indexes. Initial bone lesions were unchanged on computed tomography 25 years after diagnosis, but new bone lesions had appeared. MEN1 gene and CasR analyses were negative.

This is a rare case of a patient affected by multicentric giant cell tumours with a 25-year follow up. A slow progression of the lesion is documented, as well as the absence of significant effect of biphosphonate therapy.

Giant cell tumor (GCT) of bone is a locally destructive tumor that occurs predominantly in long bones of post-pubertal adolescents and young adults, where it occurs in the epiphysis. The majority are treated by aggressive curettage or resection. Vascular invasion outside the boundary of the tumor can be seen. Metastasis, with identical morphology to the primary tumor, occurs in a few percent of cases, usually to the lung. On occasion GCTs of bone undergo frank malignant transformation to undifferentiated sarcomas. Here we report a case of GCT of bone that at the time of recurrence was found to have undergone malignant transformation. Concurrent metastases were found in the lung, but these were non-transformed GCT.

Background

Treatment of giant cell tumor of bone (GCT) often is complicated by local recurrence. Intralesional curettage is the standard of care for primary GCTs. However, there is controversy whether intralesional curettage should be preferred over wide resection in recurrent GCTs.

Questions/purposes

We investigated the rerecurrence-free survival after surgical treatment of recurrent GCTs to determine the influence of the surgical approach, adjuvant treatment, local tumor presentation, and demographic factors on the risk of further recurrence.

Patients and Methods

We retrospectively reviewed the medical records of 46 patients with recurrent GCTs of long bones treated with wide resection or intralesional curettage and compared these cohorts. Recurrence rates, risk factors for recurrence, and the development of pulmonary metastases were determined. The minimum followup was 37 months (mean, 134 months; range, 37–337 months).

Results

The rate of rerecurrence after wide resection was 6%. Intralesional curettage showed an overall rerecurrence rate of 32%. Implantation of polymethylmethacrylate (PMMA) instead of bone grafting was associated with a lower risk of subsequent recurrence in intralesional procedures (14% versus 50%). Extracompartmental disease did not increase the risk of rerecurrence. Pulmonary metastases occurred in seven patients and appeared independent of the surgical treatment modality chosen.

Conclusions

Intralesional curettage with methylmethacrylate for recurrent GCT provided equivalent tumor control compared with resection in this retrospective study. If joint salvage is possible, we advocate this treatment over resection in recurrent GCTs to preserve the native joint articulation.

Level of Evidence

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

Background and purpose

Giant cell tumor (GCT) of the small bones (small-bone GCT) is usually rare and considered somewhat different from conventional GCT. The purpose of this study was to investigate and report the clinicopathological features of 11 cases with small-bone GCT.

Materials and methods

Patient information was obtained with the help of questionnaires. X-rays and paraffin blocks obtained from several institutions were clinically, radiographically, and histologically evaluated.

Results

Small-bone GCT was observed in younger patients compared to conventional GCT; 5 of the 11 (45%) patients were below 20 years of age, whereas the corresponding figure for all GCT patients is 16% in Japan. Excessive cortical bone expansion is a special feature. There were two cases of recurrence and one case of lung metastasis; the primary lesion was in the hand for all three cases. In contrast, no primary lesion of the foot recurred or metastasized. Varying degrees of positive p63 immunostaining were observed in all examined cases (n = 9) of small-bone GCT but were negative in case of giant cell reparative granuloma (GCRG) and solid variant of aneurysmal bone cyst (ABC). One case that demonstrated high-intensity positive staining had two episodes of recurrence.

Conclusion

Small-bone GCT tends to develop in younger patients than does conventional GCT. Primary GCTs of the hand may be biologically more aggressive than those of the feet. The p63 immunostaining may be useful not only for differential diagnosis but also for prognostication of small-bone GCT.

Background

Many surgeons treat giant cell tumor of bone (GCT) with intralesional curettage. Wide resection is reserved for extensive bone destruction where joint preservation is impossible or when expendable sites (eg, fibular head) are affected. Adjuvants such as polymethylmethacrylate and phenol have been recommended to reduce the risk of local recurrence after intralesional surgery. However, the best treatment of these tumors and risk factors for recurrence remain controversial.

Questions/purposes

We evaluated the recurrence-free survival after surgical treatment of GCT to determine the influence of the surgical approach, adjuvant treatment, local tumor presentation, and demographic factors on the risk of recurrence.

Methods

We retrospectively reviewed 118 patients treated for benign GCT of bone between 1985 and 2005. Recurrence rates, risk factors for recurrence and the development of pulmonary metastases were determined. The minimum followup was 36 months (mean, 108.4 ± 43.7; range, 36–233 months).

Results

Wide resection had a lower recurrence rate than intralesional surgery (5% versus 25%). Application of polymethylmethacrylate decreased the risk of local recurrence after intralesional surgery compared with bone grafting; phenol application alone had no effect on the risk of recurrence. Pulmonary metastases occurred in 4%; multidisciplinary treatment including wedge resection, chemotherapy, and radiotherapy achieved disease-free survival or stable disease in all of these patients.

Conclusion

We recommend intralesional surgery with polymethylmethacrylate for the majority of primary GCTs. Because pulmonary metastases are rare and aggressive treatment of pulmonary metastases is usually successful, we believe the potential for metastases should not by itself create an indication for wide resection of primary tumors.

Level of Evidence

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

Background:

The distal end of the radius is one of the common sites of involvement in giant cell tumors (GCTs) with reportedly increased propensity of recurrence. The objective of the present analysis was to study the modalities of management of the different types of distal end radius GCTs so as to minimize the recurrence rates and retain adequate function.

Materials and methods:

Twenty-four patients of distal end radius GCTs treated between January 2000 and December 2004 were retrospectively reviewed. Nineteen cases were available for follow-up with an average follow-up of 37.5 months. There was one Campanacci Grade 1 lesion, nine Grade 2 and 14 Grade 3 lesions. Thirteen (54%) of these patients were treated elsewhere earlier and presented with recurrence. The operative procedures that were performed were: curettage and cementing (five), curettage and bone grafting (seven), excision and proximal fibular arthroplasty (two), excision and wrist arthrodesis (nine) and excision of soft tissue recurrence (one).

Results:

Functional status was evaluated using Musculo Skeletal Tumor Society scoring system which averaged 78%. The recurrence rate was 32%. Complications included local recurrence (six), nonunion at the graft bone junction (one), infection (one), deformity (two), stiffness (two), subluxation (two) and bony metastasis (one).

Conclusions:

The majority of patients undergoing curettage were either Campanacci Grade 1 or 2. Patients undergoing curettage and reconstruction had a better functional result (82%) as compared to arthrodesis or fibular arthroplasty (69%). Previous intervention did not appear to increase the recurrence rates. Even though complications occur, judicious decision-making and an appropriate treatment plan can ensure a satisfactory outcome in the majority of cases.

Background

Giant cell tumor (GCT) is usually a benign but locally aggressive primary bone neoplasm in which monocytic macrophage/osteoclast precursor cells and multinucleated osteoclast-like giant cells infiltrate the tumor. The etiology of GCT is unknown, however the tumor cells of GCT have been reported to produce chemoattractants that can attract osteoclasts and osteoclast precursors. Rarely, GCT can originate at extraosseous sites. More rarely, GCT may exhibit a much more aggressive phenotype. The role of chemotherapy in metastatic GCT is not well defined.

Case presentation

We report a case of an aggressive GCT of the uterus with rapidly growing lung metastases, and its response to chemotherapy with pegylated-liposomal doxorubicin, ifosfamide, and bevacizumab, along with a review of the literature.

Conclusion

Aggressive metastasizing GCT may arise in the uterus, and may respond to combination chemotherapy.

Giant cell tumor (GCT) of bone is a benign but locally aggressive and destructive lesion generally occurring in skeletally mature individuals. Typically involving the epiphysiometaphyseal region of long bones, the most common sites include the distal femur, proximal tibia and distal radius. On radiographs, GCT demonstrates a lytic lesion centered in the epiphysis but involving the metaphysis and extending at least in part to the adjacent articular cortex. Most are eccentric, but become symmetric and centrally located with growth. Most cases show circumscribed borders or so-called geographical destruction with no periosteal reaction unless a pathological fracture is present. There is no mineralized tumor matrix. Giant cell tumor can produce wide-ranging appearances depending on site, complications such as hemorrhage or pathological fracture and after surgical intervention. This review demonstrates a spectrum of these features and describes the imaging characteristics of GCT in conventional radiographs, computerized tomography scans, magnetic resonance imaging, bone scans, positron emission tomography scans and angiography.

Giant cell tumor of bone (GCT) is a destructive neoplasm of uncertain etiology that affects the epiphyseal ends of long bones in young adults. GCT stromal cells (GCTSCs) are the primary neoplastic cells of this tumor and are the only proliferating cell component in long-term culture, which recruits osteoclast-like giant cells that eventually mediate bone destruction. The oncogenesis of GCT and factors driving the neoplastic stromal cells to proliferate extensively and pause at an early differentiation stage of pre-osteoblast lineage remain unknown. Overexpression of p63 was observed in GCTSCs and there is growing evidence that p63 is involved in oncogenesis through different mechanisms. This study aimed to understand the specific role of p63 in cell proliferation and oncogenesis of GCTSCs. We confirmed p63 expression in the mononuclear cells in GCT by immunohistochemical staining. By real-time PCR analysis, we showed a higher level (>15-fold) of TAp63 expression in GCTSCs compared to that in mesenchymal stem cells. Furthermore, we observed that knockdown of the p63 gene by siRNA transfection greatly reduced cell proliferation and induced cell cycle arrest at S phase in GCTSCs. We found that the mRNA expression of CDC2 and CDC25C was substantially suppressed by p63 knockdown at 24–72 h. Moreover, p63 was found to be recruited on the regulatory regions of CDC2 and CDC25C, which contain p53-responsive elements. In summary, our data suggest that p63 regulates GCTSC proliferation by binding to the CDC2 and CDC25C p53-REs, which may inhibit the p53 tumor suppressor activity and contribute to GCT tumorigenesis.

The characteristic bone destruction in giant cell tumour of bone (GCT) is largely attributed to the osteoclast-like giant cells. However, experimental analyses of bone resorption by cells from GCT often fail to exclude the neoplastic spindle-like stromal cells, and several studies have demonstrated that bone resorption by GCT cells is increased in the presence of stromal cells. The spindle-like stromal cells from GCT may therefore actively contribute to the bone resorption observed in the tumour. Type I collagen, a major organic constituent of bone, is effectively degraded by three matrix metalloproteinases (MMPs) known as the collagenases: MMP-1, MMP-8 and MMP-13. We established primary cell cultures from nine patients with GCT and the stromal cell populations were isolated in culture. The production of collagenases by primary cultures of GCT stromal cells was determined through real-time PCR, western blot analysis and a multiplex assay system. Results show that the cells produce MMP-1 and MMP-13 but not MMP-8. Immunohistochemistry confirmed the presence of MMP-1 and MMP-13 in paraffin-embedded GCT tissue samples. Medium conditioned by the stromal cell cultures was capable of proteolytic activity as determined by MMP-1 and MMP-13-specific standardized enzyme activity assays. The spindle-like stromal cells from GCT may therefore actively participate in the bone destruction that is characteristic of the tumour.

Giant Cell Tumor of Bone (GCT) is an aggressive skeletal tumor characterized by local bone destruction, high recurrence rates and metastatic potential. Previous work in our lab has shown that the neoplastic cell of GCT is a proliferating pre-osteoblastic stromal cell in which the transcription factor Runx2 plays a role in regulating protein expression. One of the proteins expressed by these cells is parathryroid hormone-related protein (PTHrP). The objectives of this study were to determine the role played by PTHrP in GCT of bone with a focus on cell proliferation and apoptosis. Primary stromal cell cultures from 5 patients with GCT of bone and one lung metastsis were used for cell-based experiments. Control cell lines included a renal cell carcinoma (RCC) cell line and a human fetal osteoblast cell line. Cells were exposed to optimized concentrations of a PTHrP neutralizing antibody and were analyzed with the use of cell proliferation and apoptosis assays including mitochondrial dehydrogenase assays, crystal violet assays, APO-1 ELISAs, caspase activity assays, flow cytometry and immunofluorescent immunohistochemistry. Neutralization of PTHrP in the cell environment inhibited cell proliferation in a consistent manner and induced apoptosis in the GCT stromal cells, with the exception of those obtained from a lung metastasis. Cell cycle progression was not significantly affected by PTHrP neutralization. These findings indicate that PTHrP plays an autocrine/paracrine neoplastic role in GCT by allowing the proliferating stromal cells to evade apoptosis, possibly through non-traditional caspase-independent pathways. Thus PTHrP neutralizing immunotherapy is an intriguing potential therapeutic strategy for this tumor.

ABSTRACT

Objective: To discuss the current management options for giant-cell tumors (GCTs) involving the temporal bone and present two case reports and a review of the literature. Method: In a tertiary-care academic medical center, two patients with GCTs of the temporal bone were evaluated and managed. The patients underwent gross total resection and curettage of GCTs involving the temporal bone. Afterward, both patients were evaluated for postoperative complications as well as for recurrence. Results: Two patients underwent operative excision using curettage. Clinical and radiographic studies demonstrated no evidence of recurrence with 3 years of follow-up in one patient and 10 years of follow-up in the second patient. Conclusion: Based on these results, we concluded that gross total removal and curettage of GCTs in the temporal bone is a viable treatment option. This finding is contrary to previous studies.

Giant cell tumour (GCT) or osteoclastoma is a benign locally aggressive tumour with a tendency for local recurrence. 85–90% of cases occur in long bones; the sites most commonly affected being lower end of femur, upper end of tibia, lower end of radius and proximal humerus in descending order of frequency. Only 2% of GCT occurs in hand. GCT of bone accounts for 5% of all primary bone tumour. 80% of patients are above the age of 18 years, and it occurs commonly in adults between ages of 20 and 40 years. The authors report a case of GCT of first metacarpal which is very rare site for such tumour and only few cases reported in literature so far.

Giant cell tumor (GCT) is classified as a benign bone tumor, and it is frequently identified at the epiphysis of long bones and relatively rare in the temporal bone. For orthopedists expert at recognizing bone and soft tissue tumors, the diagnosis of GCT is relatively easy; however, since head and neck surgeons experience few cases of GCT, it may be difficult to diagnose when it occurs in the temporal bone. A 32-year-old man complained of left hearing loss, aural fullness, and tinnitus. Examination of the ear revealed a bulging tumor. Audiologic examination demonstrated conductive hearing loss of the left ear. Computer tomograph of the temporal bone showed a soft-tissue-density specification indicating bone destruction at the left temporal bone. The tumor invaded the skull base. Imaging examinations using magnetic resonance imaging revealed a nonhomogenous isosignal intensity area on T1 at the left temporal bone. After intravenous gadolinium, the mass showed unequal enhancement. This patient subsequently underwent surgery to remove the lesion using transmastoid and middle fossa approach. Pathological examinations from specimens of the tumor revealed characteristic of GCT. No clinical or radiological evidence of tumor recurrence was detected for 4 years.

Background. We report on 19 cases of giant cell tumor of bone (GCT) affecting the spine or sacrum and evaluate the outcome of different treatment modalities. Methods. Nineteen patients with GCT of the spine (n = 6) or sacrum (n = 13) have been included in this study. The mean followup was 51.6 months. Ten sacral GCT were treated by intralesional procedures of which 4 also received embolization, and 3 with irradiation only. All spinal GCT were surgically treated. Results. Two (15.4%) patients with sacral and 4 (66.7%) with spinal tumors had a local recurrence, two of the letter developed pulmonary metastases. One local recurrence of the spine was successfully treated by serial arterial embolization, a procedure previously described only for sacral tumors. At last followup, 9 patients had no evidence of disease, 8 had stable disease, 1 had progressive disease, 1 died due to disease. Six patients had neurological deficits. Conclusions. GCT of the axial skeleton have a high local recurrence rate. Neurological deficits are common. En-bloc spondylectomy combined with embolization is the treatment of choice. In case of inoperability, serial arterial embolization seems to be an alternative not only for sacral but also for spinal tumors.

Giant cell tumor (GCT) of bone though one of the commonest bone tumors encountered by an orthopedic surgeon continues to intrigue treating surgeons. Usually benign, they are locally aggressive and may occasionally undergo malignant transformation. The surgeon needs to strike a balance during treatment between reducing the incidence of local recurrence while preserving maximal function.

Differing opinions pertaining to the use of adjuvants for extension of curettage, the relative role of bone graft or cement to pack the defect and the management of recurrent lesions are some of the issues that offer topics for eternal debate.

Current literature suggests that intralesional curettage strikes the best balance between controlling disease and preserving optimum function in the majority of the cases though there may be occasions where the extent of the disease mandates resection to ensure adequate disease clearance.

An accompanying treatment algorithm helps outline the management strategy in GCT.

Giant cell tumor of bone (GCT) is a destructive and potentially metastatic bone tumour in which the characteristic giant cells have classically been considered the culprits in bone destruction. However, the neoplastic element of the tumour consists of propagative osteoblast-like stromal cells that may play a role in bone resorption. The objectives of this study were to determine the expression and activity of the gelatinases, matrix metalloproteinase (MMP)-2 and -9, in GCT stromal cells, and to determine if these cells have bone-resorbing capabilities. We performed immunohistochemistry on clinical specimens, and real-time polymerase chain reaction (PCR) and zymography on cell lysates and conditioned media from cultured clinical GCT specimens in order to evaluate the expression and activity of MMP-2 and-9 in GCT stromal cells. Our results support the fact that GCT stromal cells express MMP-2 and MMP-9 and are capable of gelatin degradation in vitro. These cells may therefore play a role in bone destruction in GCT.

The majority of giant cell tumors (GCTs) occur in the ends of the long bones. The presence of more than one GCT in the axial skeleton is rare. A GCT is capable of remaining clinically latent following treatment and becoming active a number of years later. We report an extremely rare case of GCT occurring in the axial skeleton, involving the sacrum, thoracic spine and parieto-occipital skull in more than 15 years of follow-up.

Serum tartrate-resistant acid phosphatase (TRACP) 5b was investigated for use as a marker for diagnosis of giant cell tumor (GCT) of bone and for detection of its recurrence.

Four patients with GCT of bone who were initially referred to our hospital were classified as a primary group. Three patients who had local recurrence following curettage were classified as a local recurrence group. Five with no recurrence were classified as a no-recurrence group. Eighteen patients with primary and metastatic malignant bone tumors were also enrolled in the study as a control group. Serum TRACP 5b was measured before the biopsy in all patients and was measured periodically after the operation in patients with GCT of bone. Student t-tests were used for statistical analyses.

TRACP 5b was greater than 1500 Um/dL in all primary group patients. Mean TRACP 5b values decreased gradually with post-operative time, showing lower values until local recurrence. The mean value of TRACP 5b of the local recurrence group (753 ± 68.7 mU/dL) was significantly higher than that of the no-recurrence group (340.6 ± 78.3 mU/dL). The mean value of TRACP 5b of the control group (466.9 ± 130.3 mU/dL) was much lower than that of the primary group and markedly lower than that of the local recurrence group. However, no significant difference was found between the no-recurrence group and the control group.

Serum TRACP 5b is a useful and convenient marker for diagnosing GCT of bone and for predicting its recurrence.

Purpose

Late relapse (LR) of germ cell tumor (GCT) is a well recognized entity associated with poor survival. We report on our experience with LR and determine predictors of survival.

Patients and Methods

From 1990 to 2004, 75 patients were managed for LR of GCT at our institution. Clinical and pathologic parameters were reviewed. Estimates of cancer-specific survival were generated using the Kaplan-Meier method, and a Cox proportional hazards model was used to assess potential predictors of outcome.

Results

The median time to LR was 6.9 years (range, 2.1 to 37.7 years). Overall, 56 patients (75%) had LR in the retroperitoneum, including 25 (93%) of 27 patients initially managed without retroperitoneal lymph node dissection. The 5-year cancer-specific survival (CSS) was 60% (95% CI, 46% to 71%). Patients who underwent complete surgical resection at time of LR (n = 45) had a 5-year CSS of 79% versus 36% for patients without complete resection (n = 30; P < .0001). The 5-year CSS for chemotherapy-naive patients was significantly greater than patients with a prior history of chemotherapy as part of their initial management (5-year CSS, 93% v 49%, respectively). In multivariable analysis of pretreatment parameters available at the time of LR, the presence of symptoms (hazard ratio [HR] = 4.9) and multifocal disease (HR = 3.0) were associated with an inferior CSS.

Conclusion

The data suggest that meticulous control of the retroperitoneum is critical to prevent LR in the retroperitoneum. In multivariable analysis, patients with a symptomatic presentation and those with multifocal disease have a significantly decreased survival. Survival is greatly improved if complete surgical excision of disease is attained.

Background

Giant cell tumors (GCTs) of bone are primary benign bone tumors that are characterized by a high number of osteoclast-like multinuclear giant cells (MNCs). Recent studies suggest that the spindle-shaped stromal cells in GCTs are tumor cells, while monocyte-like cells and MNCs are reactive osteoclast precursor cells (OPCs) and osteoclasts (OCs), respectively. In this study, we investigated the pathogenesis of osteoclastic bone destruction in GCTs by focusing on the role of the vascular endothelial growth factor (VEGF)-Flt-1 (type-1 VEGF receptor)-focal adhesion kinase (FAK) pathway.

Methods

The motility of OPCs cells was assessed by a chemotaxis assay and the growth of OPCs was examined using a cell proliferation assay. The expression of VEGF and activation of Flt-1 and FAK in clinical GCT samples and in OPCs were detected by immunohistochemistry and immunoblotting. The correlation between the expression levels of activated Flt-1 and FAK and clinical stages of GCTs was investigated by immunohistochemistry.

Results

In GCT samples, CD68, a marker of OPCs and OCs, co-localized with Flt-1. Conditioned media from GCT tissue (GCT-CM) enhanced the chemotaxis and proliferation of OPCs. GCT-CM also stimulated FAK activation in OPCs in vitro. Moreover, there was a correlation between the clinical stage of GCTs and the expression of tyrosine-phosphorylated Flt-1 and FAK.

Conclusions

Our results suggest that the VEGF-Flt-1-FAK pathway is involved in the pathogenesis of bone destruction of GCTs.

Giant cell tumor of bone (GCT) is an aggressive bone tumor consisting of multinucleated osteoclast-like giant cells and proliferating osteoblast-like stromal cells. The signaling mechanism involved in GCT stromal cell osteoblastic differentiation is not fully understood. Previous work in our lab reported that GCT stromal cells express high levels of TWIST1, a master transcription factor in skeletal development, which in turn down-regulates Runx2 expression and prevents terminal osteoblastic differentiation in these cells. The purpose of this study was to determine the upstream regulation of TWIST1 in GCT cells. Using GCT stromal cells obtained from patient specimens, we demonstrated that fibroblast growth factor receptor (FGFR)-2 signaling plays an essential role in bone development and promotes differentiation of immature osteoblastic cells. Fibroblast growth factor (FGF)-2 stimulates FGFR-2 expression, resulting in decreased TWIST1 expression and increased Runx2, alkaline phosphastase (ALP) and osteopontin (OPN) expression. Inhibition of FGFR-2 through siRNA decreased the expression of ALP, Runx2 and OPN in GCT stromal cells. Our study also confirmed that FGF-2 ligand activates downstream ERK1/2 signaling and pharmacological inhibition of the ERK1/2 signaling pathway suppresses FGF-2 stimulated osteogenic differentiation in these cells. Our results indicate a significant role of FGFR-2 signaling in osteoblastic differentiation in GCT stromal cells.

Introduction

While testicular germ cell tumors (TGCTs) are the most common malignancy in young men, germ cell tumors in women are uncommon. Familial clustering, epidemiologic evidence of increased risk with family or personal history of TGCT, and associations with genitourinary tract anomalies suggest an underlying genetic predisposition to TGCT, but traditional linkage studies have yet to identify a highlypenetrant TGCT cancer susceptibility gene. In this paper, we investigate the familial occurrence of testicular and ovarian germ cell tumors.

Methods

We report a family in which a TGCT and an ovarian germ cell tumor (OGCT) occurred in two siblings, summarize the existing literature on familial occurrences of OGCT, either alone or in combination with extragonadal or TGCTs, and compare the incidence of familial and sporadic testicular and ovarian GCTs. Sporadic GCT data were obtained from the US Surveillance Epidemiology and End Results (SEER) registry.

Results

We identified 16 reports of OGCT occurring in conjunction with either ovarian, testicular or extragonadal GCT. In these familial cases, the mean age at onset of female dysgerminoma was younger than that noted in the general population (age 17 vs age 24, p=0.01). In SEER, the incidence of TGCT was 15 times higher than that of OGCT. Histologic distributions in males and females showed distinctly different patterns.

Discussion

Although the incidence of OGCTs in the general population is quite low, its occurrence in multiple members of the same family and in families with TGCT suggests that a gene conferring susceptibility to GCTs may exist in some families.

Background and purpose

Giant cell tumor of bone (GCT) is sometimes difficult to distinguish from other giant-cell-rich tumors such as chondroblastoma (CHB) and aneurysmal bone cyst (ABC). The usefulness of p63 as a diagnostic marker for GCT is controversial. While there have been no reports about p63 as a prognostic marker for local recurrence, various p63-positive rates in GCT have been reported. The purpose of this study was to investigate retrospectively whether p63 is useful as a diagnostic marker and/or a prognostic marker for local recurrence of GCT.

Methods

This study included 36 patients diagnosed with either GCT (n = 16), CHB (n = 9), ABC (n = 7), or non-ossifying fibroma (NOF) (n = 4). p63 immunostaining was performed for all specimens. The mean p63-positive rate was compared with the four diseases and between the recurrent and non-recurrent cases of GCT.

Results

Although the mean p63-positive rate for GCT (36.3%) was statistically higher than that of all other diseases examined (CHB: 15.2%; ABC: 5.8%; NOF: 3.4%), p63 was not specific for GCT. The mean p63-positive rate for recurrent GCT cases (73.6%) was statistically higher than that for non-recurrent cases (29.1%).

Conclusion

In the diagnosis of GCT, p63 is a useful but not a conclusive marker. However, p63 did appear to indicate the biological aggressiveness of GCT. Therefore, p63 may help surgeons to estimate the risk of recurrence after surgery and help them to choose the best treatment for each GCT case.