[Solitary bone cysts of the pelvis. A frequently misinterpreted entity]. / Solitäre Knochenzysten des Beckens. Eine häufig verkannte Entität.

Solitary bone cyst of the pelvis is a rare lesion. The diagnosis is relatively simple providing sufficient material is accumulated during biopsy or surgery. Calcifying forms often cause difficulties in terms of differential diagnosis. Radiographic imaging can be complex when examining large lesions of the pelvis. Biopsy is the method of choice for definitive diagnosis, which should be verified against material gathered surgically or during curettage. Bone tumors of the pelvis have to be considered in the differential diagnosis of the lesion. Large cystic lesions of the pelvis in particular are to be reviewed pathohistologically to avoid false diagnosis. The consequences for the patient in terms of quality of life and life expectancy can be serious. The need for interdisciplinary cooperation is greater than ever to ensure correct diagnosis and therapy of bone lesions.

Allocation of nonbirefringent wear debris: darkfield illumination associated with PIXE microanalysis reveals cobalt deposition in mineralized bone matrix adjacent to CoCr implants.

Abrasive joint replacement material that accumulates in the tissue induces reciprocal effects between prosthesis material and organism. Since the limitations of brightfield and polarized light microscopy for foreign body analysis are well known, a method was applied that ensures the detailed histological assessment of nonbirefringent particles in periprosthetic soft and hard tissue. Cemented and cementless interface regions of five selected autopsy hip implant cases (2 x Endo-Modell Mark III, LINK, 1 x St. Georg Mark II, LINK, Germany; 2 x Spongiosa Metal II, ESKA, Germany) were viewed under darkfield illumination and subsequently analyzed with proton-induced X-ray emission (PIXE). Eight autopsy cases without implants served as controls. Using darkfield illumination technique, metallic particles became visible as luminous points under the microscope. The majority of particles in the samples from the cemented cases were degradation products of radiopaque bone cement. There was minimal evidence of metallic alloy particles in the soft tissues. However, a considerable quantity of heavy metal cobalt (Co) was found in the periprosthetic mineralized bone tissue, which was not observed in the controls. The periprosthetic concentration of cobalt ranged from 38 to 413 ppm. The findings demonstrate a correlation between cobalt concentration, time since implantation, and distance from the implant. Darkfield microscopy associated with PIXE enables a detailed histological assessment of metal particles in the tissue. In an effort to optimize biomechanics, implant design and implantation techniques, the contamination of soft and hard tissue with heavy metal degradation products deserves similar attention in terms of alloy assortment.

[Polyethylene abrasion: cause or consequence of an endoprosthesis loosening? Investigations of firm and loosened hip implants]. / Polyethylen-Abrieb: Ursache oder Folge einer Endoprothesenlockerung? Untersuchungen an festen und gelockerten Hüftendoprothesen.

AIM: Periprosthetic tissue was analysed by the combination of different investigation techniques without destruction. The localisation and geometry of polyethylene abrasion particles were determined quantitatively to differentiate between abrasion due to function and abrasion due to implant loosening. Non-polyethylene particles from implant components which contaminate the tissue were micro-analytically measured. The results will help us to understand loosening mechanisms and thus lead to implant optimisations. METHOD: A non-destructive particle analysis using highly sensitive proton-induced X-ray emission (PIXE) was developed to achieve a better histological allocation. Five autopsy cases with firmly fitting hip endoprosthesis (2 x Endo-Modell Mark III, 1 x St. Georg Mark II, LINK, Germany; 2 x Spongiosa Metal II, ESKA, Germany) were prepared as ground tissue specimens. Wear investigations were accomplished with a combined application of different microscopic techniques and microanalysis. The abrasion due to implant loosening was histologically evaluated on 293 loosened cup implants (St. Georg Mark II, LINK, Germany). RESULTS: Wear particles are heterogeneously distributed in the soft tissue. In cases of cemented prostheses, cement particles are dominating whereas metal particles could rarely be detected. The concentration of the alloy constituent cobalt (Co) is increased in the mineralised bone tissue. The measured co-depositions depend on the localisation and/or lifetime of an implant. Functional polyethylene (PE) abrasion needs to be differentiated from PE abrasion of another genesis (loosening, impingement) morphologically and by different tissue reactions. CONCLUSION: In the past a reduction of abrasion was targeted primarily by the optimisation of the bearing surfaces and tribology. The interpretation of our findings indicates that different mechanisms of origin in terms of tissue contamination with wear debris and the alloy should be included in the improvement of implants or implantation techniques.

Cementless fixation of megaprostheses using a conical fluted stem in the treatment of bone tumours.

We reviewed 25 patients in whom a MUTARS megaprosthesis with a conical fluted stem had been implanted. There were three types of stem: a standard stem was used in 17 cases (three in the proximal femur, nine in the distal femur and five proximal tibia), a custom-made proximal femoral stem in four cases and a custom-made distal femoral stem in four cases. The mean age of the patients was 40.1 years (17 to 70) and the mean follow-up was for 2.5 years (0.9 to 7.4). At follow-up two patients had died from their disease: one was alive with disease and 22 were disease-free. One of 23 prostheses had been removed for infection and another revised to a cemented stem. The mean Musculoskeletal Tumor Society score was 24.9 (12 to 30) and the mean Karnofsky index was 82% (60% to 100%). There was no radiological evidence of loosening or subsidence. Stem stress shielding was seen in 11 patients and was marked in five of these. There were five complications, rupture of the extensor mechanism of the knee after extra-articular resection in two patients, deep venous thrombosis in one, septic loosening in one, and dislocation of the hip in one. The survival rate after seven years was 87% (95% confidence interval (CI) 83 to 91) for the patients and 95% (95% CI 91 to 99) for the megaprosthesis. A longer follow-up is needed to confirm these encouraging results.

Glucocorticosteroid-induced osteoporosis in adult primiparous Göttingen miniature pigs: effects on bone mineral and mineral metabolism.

Information on the pathophysiology of glucocorticoid-induced osteoporosis (GIO) is limited, since its clinical picture often reflects a combined effect of glucocorticoids (GC) and the treated systemic disease (i.e., inflammation and immobility). In 50 healthy adult (30-mo-old) primiparous Göttingen minipigs, we studied the short-term (8 mo, n = 30) and long-term (15 mo, n = 10) effect of GC on bone and mineral metabolism longitudinally and cross-sectionally compared with a control group (n = 10). All animals on GC treatment received prednisolone orally at a dose of 1.0 mg x kg body wt(-1) x day(-1) for 8 wk and thereafter at 0.5 mg/kg body wt(-1) x day(-1). In the short term, GC reduced bone mineral density (BMD) at the lumbar spine by -47.5 +/- 5.1 mg/cm(3) from baseline (P < 0.001), which was greater (P < 0.05) than the loss [not significant (NS)] in the control group of -11.8 +/- 12.6 mg/cm(3). Calcium absorption decreased from baseline by -2,488 +/- 688 mg/7 days (P < 0.001) compared with -1,380 +/- 1,297 mg/7 days (NS) in the control group. Plasma bone alkaline phosphatase (BAP) decreased from baseline by -17.8 +/- 2.2 U/l (P < 0.000), which was significantly different (P < 0.05) from the value of the control group of -1.43 +/- 4.8 U/l. In the long term, the loss of BMD became more pronounced and bone mineral content (BMC), trabecular thickness, mechanical stability, calcium absorption, 25-hydroxyvitamin D(3), 1,25-dihydroxyvitamin D(3), and parathyroid hormone tended to be lower compared with the control group. There was a negative association between the cumulative dose of GC and BMD, which was associated with impaired osteoblastogenesis. In conclusion, the main outcomes after GC treatment are comparable to symptoms of GC-induced osteoporosis in human subjects. Thus the adult Göttingen miniature pig appears to be a valuable animal model for GC-induced osteoporosis.

[Pathohistology of femoral head necrosis]. / Pathohistologie der Femurkopfnekrose.

Necrosis of the femoral head represents a special form of aseptic bone necrosis because it develops in the high load-bearing region of the hip joint. The incidence of the disease is not precisely known. Characteristic macroscopic findings include articular cartilage detachment in the load-bearing zone immediately below the subchondral osseous lamella, the bordering necrosis of the marrow space and bone cells, incursion of the spongiosa, and the gradual loss of roundness of the femoral head. The cause of the disease is a disorder in circulation supplying the proximal femur. The disease frequently occurs in disorders of lipometabolism, after steroid medication, in sickle cell anemia and chronic alcoholism, and after fractures of the femoral neck. Histopathological classification should distinguish between arthropathy with secondary femoral head necrosis and primary forms. Differential diagnosis based on histological findings should distinguish between primary coxarthrosis with secondary femoral head necrosis, metastases, and a few bone tumors in the epiphyses. Clear cell chondrosarcoma is particularly important in the context.

Ibandronate treatment reverses glucocorticoid-induced loss of bone mineral density and strength in minipigs.

The Göttingen minipig is one of the few large animal models that show glucocorticoid (GC)-induced bone loss. We investigated whether GC-induced loss of bone mineral density (BMD) and bone strength in minipigs can be recovered by treatment with the bisphosphonate ibandronate (IBN). 40 primiparous sows were allocated to 4 groups when they were 30 months old: GC treatment for 8 months (GC8), for 15 months (GC15), GC treatment for 15 months plus IBN treatment for months 8-15 (GC&IBN), and a control group without GC treatment. Prednisolone was given at a daily oral dose of 1 mg/kg body weight for 8 weeks and thereafter 0.5 mg/kg body weight. IBN was administered intramuscularly and intermittently with an integral dose of 2.0 mg/kg body weight. BMD of the lumbar spine (L1-3) was assessed in vivo by Quantitative Computed Tomography (QCT) at months 0, 8, and 15. Blood and urine samples were obtained every 2-3 months. After sacrificing the animals lumbar vertebrae L4 were tested mechanically (Young's modulus and ultimate stress). Histomorphometry was performed on L2 and mineral content determined in ashed specimens of T12 and L4. In the GC&IBN group, the GC associated losses in BMD of -10.5%+/-1.9% (mean+/-standard error of the mean, p<0.001) during the first 8 months were more than recovered during the following 7 months of IBN treatment (+14.8%+/-1.2%, p<0.0001). This increase was significantly larger (p<0.0001) than the insignificant +2.1%+/-1.2% change in group GC15. At month 15, the difference between groups GC&IBN and GC15 was 22% (p<0.01) for BMD, 48% (p<0.05) for Young's modulus, and 31% (p<0.14) for ultimate stress; bone-specific alkaline phosphatase showed trends to lower values (p<0.2) while deoxypyridinoline was comparable. This minipig study demonstrates that GC-induced impairment of bone strength can be effectively and consistently treated by IBN. GC&IBN associated alterations in BMD and bone turnover markers can be monitored in vivo using QCT of the spine and by biochemical analyses, reflecting the changes in bone strength.

[Bone metastasis of prostatic cancer imitating Paget's sarcoma]. / Ossäre Metastase eines Prostatakarzinoms simuliert ein Paget-Sarkom.

HISTORY AND CLINICAL FINDINGS: A 74-year-old man presented with bone pain of the right hip, night sweat and weight loss for 18 months. The diagnosis of Paget's disease was confirmed four months before admission, but pain and elevated serum alkaline phosphatase levels remained despite treatment with i.v. bisphosphonates. The physical examination showed no specific abnormalities. INVESTIGATIONS: Laboratory findings were elevated levels of serum alkaline phosphatase (AP), CA 19-9 and CEA. Radiological and tomographic images showed an aggressive periostal reaction consistent with Paget's sarcoma. The bone biopsy revealed the presence of prostatic cancer which was confirmed in a subsequent prostate biopsy. TREATMENT AND COURSE: Because of the multiple bone and lung metastases the disease proved to be incurable and the patient received palliative therapy with flutamide. He died 12 months later. CONCLUSION: In patients with Paget's disease lacking of response to bisphosphonate administration (permanently increased AP and sustained pain) radiological and clinical re-assessment of the diagnosis is indicated and may sometimes also include bone biopsy.

Biomechanical, morphological, and histological analysis of early failures in hip resurfacing arthroplasty.

The present revival of hip resurfacing arthroplasty may be related to an increase in early failures owing to the challenging technique of the procedure. Fifty-five retrieved implants were analysed with respect to wear, cement mantle and cement penetration, fracture and head morphology, as well as standard histology. Femoral neck fractures occurred in median after 102 days. The time to failure was shorter for older women. Major deviations from the suggested cement mantle thickness and cement penetration were found. Indications for high trauma during implantation leading to early failure due to weakening of the femoral neck were also observed. Some failures had signs of pseudarthrosis beneath the implant. Four different fracture patterns with different mean survival times were identified. Observed wear was minor with the exception of that due to alignment mistakes (rim loading). The cups were not damaged by the failures. Histological results indicate that avascular necrosis is not necessarily connected with this kind of endoprosthetic surgery. Most of the failures analysed can probably be attributed to the 'learning curve' effect, which is an unsatisfactory situation.

Transiliac bone biopsy in osteoporosis: frequency, indications, consequences and complications. An evaluation of 99 consecutive cases over a period of 14 years.

Bone biopsy is a diagnostic procedure restricted to untypical, unclear and complicated cases in evidence-based guidelines on diagnosis and treatment of osteoporosis. Its relevance has been a topic of recent controversial discussion. This study was performed to evaluate its role and relevance in routine use. A total of 99 horizontal transiliac bone biopsies performed over a time period of 14 years because of an osteological indication in one single centre were analysed, which reflects that bone biopsy followed about 0.003% of patients' consultations. Bone biopsies were indicated for osteoporotic males (n = 63) and premenopausal osteoporotic females (n = 18) without endocrine abnormality and normal immunofixation (serum and urine), suspected systemic/malignant disease such as mastocytosis, osteogenesis imperfecta, non-secreting plasmocytoma, metastatic infiltration (n = 16) and decreasing bone mineral density under anti-osteoporotic treatment (n = 2). The most frequent diagnoses besides osteoporosis were normal histology, borderline finding towards mild osteoporosis, and osteoporomalacia with relevant osteoidosis. In some cases, pathological findings in bone marrow were detected. In most cases (82/99), bone biopsy led to consequences in medical treatment. Following histopathological diagnosis, 16 patients did not receive any anti-osteoporotic treatment. In six patients, further diagnostic procedures were initiated because of bone histology. Bone biopsy was well tolerated and complications were rare and mild. In conclusion, despite all progress in non-invasive diagnostic procedures for metabolic bone diseases such as osteoporosis, there remains a small but significant subset of patients who may benefit from inclusion of bone biopsy into the diagnostic procedure.

[Fluorosis--a forgotten entity. Case report of a woman with coxarthrosis and newly diagnosed fluorosis]. / Fluoridosteopathie--eine vergessene Entität. Gleichzeitiges Auftreten von Coxarthrose und bis dahin unbekannter Fluoridosteopathie bei einer 73-jährigen Patientin.

The clinical manifestation of fluorosis has become rare over the past years. Although the use of fluoride medication in osteoporosis therapy remains controversial, past study results have led to a reduction in fluoride prescriptions. Several studies have shown minor biomechanical properties of newly built woven bone compared to original bone. Despite new prescription protocols, fluoride therapy should not be disregarded in the anamnesis of osteoporosis patients. In addition to conventional diagnostics in fluorosis, new techniques such as microanalysis and micro-CT-analysis show a diagnostic benefit. In this case, the edx-microanalysis results show an F concentration of over 1.0 wt% in bone. The ratio of bone to tissue volume, evaluated by micro-CT, is clearly elevated at 46% BV/TV. The histopathological preparation of the femoral head has made the possible effects of fluoride medication on bone visible and quantifiable. A direct causal relationship between coxarthrosis and fluoride medication, found both in our patient as well as in the literature, has not been demonstrated. In order to better understand the broad effects of fluoride medication in combination with coxarthrosis more studies are needed.

[Melorheostosis of the foot: a case report of a rare entity]. / Melorheostose des Fusses: Falldarstellung eines seltenen Krankheitsbildes.

INTRODUCTION: Melorheostosis is a rare bony dysplasia and often recognised just sporadically by chance. CASE REPORT: We present a case of a 15 year old girl who presented a melorheostosis of the left foot. After birth there was recognized a shortening and deformity of the 2nd toe on the left foot. Furthermore she had an interphalangeal hallux valgus that displaced the 2nd toe increasingly. Thus in the last years there were more and more difficulties to wear normal shoes. Conservative therapy was not successful. We performed a lengthening extending osteotomy of the 2nd toe (a modified Weil osteotomy) and an Akin osteotomy of the interphalangeal hallux valgus. Since the surgical procedure the patient is out of any complaints. DISCUSSION: We demonstrate the radiologic and histologic findings and discuss the relevant literature and possible etiology.

[Cartilage tumors. Classification, conditions for biopsy and histologic characteristics]. / Knorpelbildende Tumoren Klassifikation, Voraussetzungen für die Biopsie und histologische Charakteristika.

Primary cartilage-forming tumors of the bone are a large group among the rare bone tumors. The clinical and radiographic findings of the different entities show similar findings. Bone biopsy is still the most relevant examination in the final diagnosis of the lesion. The requirements for a correct biopsy and the main features of the macroscopic and histologic findings of cartilage tumors are presented from the viewpoint of the pathologist. Differentiation between benign enchondroma and grade I chondrosarcoma requires close interdisciplinary cooperation to avoid over-treatment and relapse. Rare low-grade malignant cartilage tumors such as clear-cell chondrosarcoma need to be diagnosed in specialized centres to arrive at the correct therapy. The morphologic features of mesenchymal chondrosarcoma, clear-cell chondrosarcoma and secondary chondrosarcoma in osteochondroma are demonstrated. The aim is to correlate the morphologic and radiographic features. The same applies to benign entities such as osteochondroma, chondroblastoma and chondromyxoid fibroma.

[Principles of fixation of the cementless modular revision stem Revitan]. / Fixationsprinzipien des zementlosen modularen Hüftrevisionsschaftes Revitan. Eine anatomische Studie.

AIM AND METHOD: To analyse the femoral fixation of a modular cementless revision endoprosthesis, eight prosthetic combinations of the Revitan-System (Centerpulse, Winterthur, Switzerland) were implanted in four cadavers. On three cadavers a curved revision Revitan stem was implanted by an endofemoral approach on one side and by a transfemoral approach on the contralateral side. On the fourth cadaver a straight Revitan stem was implanted on one side and a curved Revitan stem on the contralateral side using a transfemoral approach. Transversal slides of 7-8 mm thickness were performed at the fixation areas of each implant and the implant-bone contact was analysed macroscopically and using contact radiography. RESULTS: The straight stem implanted by a transfemoral approach showed a double-conical press-fit fixation with cutting of the eight longitudinal fins into the cortical bone. The curved revision stems implanted by the same approach had a circular surface fixation similar to the press-fit fixation of the straight stem. In contrast, the curved stems implanted by the endofemoral approach (without a window) showed a three-surface fixation. Hereby the two distal fixation areas led to the primary implant stability by three of the four double edges of the octagonal cross-sectional area cutting into the cortical bone. At the proximal fixation zone the implant only had contact of two implant double edges to the cortical bone. CONCLUSION: Different approaches for implantation lead to different fixation techniques of a curved revision stem. This should be considered by analysing postoperative sintering rates of cementless revision stems.

Dedifferentiated chondrosarcoma--a fatal disease.

BACKGROUND: We report on 13 patients with dedifferentiated chondrosarcomas. The mean age of the patients at diagnosis was 59.8 years. Nine patients were classified as stage IIB and four as stage III. METHODS: In 11/13 cases surgery was performed. Mostly, limb salvage with tumour resection and implantation of a megaprosthesis was done; three patients needed amputation or disarticulation. In one out of three patients with a pelvic tumour resection was followed by implantation of a pelvic replacement; the other two patients received tumour resection with autologous stabilisation of the pelvis. Surgical margins were wide in six patients, marginal in two and intralesional in three. Adjuvant chemotherapy was given to five patients. RESULTS: Recurrence was detected in 5/11 of the patients operated on: in two with wide, in one with marginal, and in two with intralesional resection. No recurrence was seen in 5/11 patients: in four after wide and in one after marginal resection. In one patient the stage was unknown. At follow-up 11 patients were dead of disease (DOD), one dead of unknown reason (DOU) and one alive with disease (AWD). The mean survival time was 9.7 months. Metastasis to different anatomical sites was evident after a period of 10 months. CONCLUSIONS: Our results resemble those reported in the literature. DDCS is rare and is the primary malignant bone tumour with the worst prognosis. Surgery is the most important procedure, although it is unclear whether a radical resection improves the long-term results. Information regarding neoadjuvant and/or adjuvant therapy with chemotherapy is very limited.

[Clear cell chondrosarcoma of the larynx. A rare tumor in an uncommon location]. / Klarzellchondrosarkom des Larynx. Ein sehr seltener Tumor in einer aussergewöhnlichen Lokalisation.

Clear cell chondrosarcoma is a rare bone tumor of low malignancy. It constitutes only 2% of all chondrosarcomas and shows a particular predilection for the epiphyses of long bones. So far, there have only been three cases of clear cell chondrosarcoma of the larynx published in the literature. We report the case of a 46 year old man who suffered from slowly worsening dyspnoea. Diagnostic evaluation revealed a directly subglottic stenosis of the larynx, narrowing the lumen to 1/3. When we tried to resect the stenosis via splitting the ring cartilage from outside, tumorous infiltration of the whole ring cartilage was found. Extended biopsies were taken and histology revealed a clear cell chondrosarcoma. The therapy of choice for this tumor is wide surgical resection. Additional radio- and/or chemotherapy are not recommended. Therefore, the patient underwent laryngectomy. Histologically, the clear cell chondrosarcoma can be easily confused with the highly malignant osteosarcoma or the conventional chondrosarcoma, both requiring more aggressive treatment. Thus, clear cell chondrosarcoma should be kept in mind and, when necessary, a reference histology by a bone tumor register should be requested.

First inventory of resorption lacunae on rods and plates of trabecular bone as observed by scanning electron microscopy.

In the present study a novel systematic distribution scheme of resorption lacunae (RL) was applied using scanning electron microscopy. RL, classified as either reticulate patch resorption lacunae (RPR) or as longitudinally extended resorption lacunae (LER) [11, were analyzed and quantified according to their localizations on rods (middle, nodes or both) and plates (central or peripheral) in standardized segments from the femoral head of 24 Caucasian subjects without bone disease. Age and gender variations were explored. No clear gender-related distribution pattern could be detected on plates. On rods of males, however, the distribution of RL tended to be higher at the nodes, but seemed to be more prevalent in the middle or extended from the middle to the nodes of rods in females. Certain other non-conclusive tendencies in relation to age, gender, type of RL and localization were observed.

[Calcaneal cyst: a classical simple bone cyst?]. / Die Kalkaneuszyste: eine klassische solitäre Knochenzyste?

INTRODUCTION: In the calcaneus differentiation between a solitary cyst and intraosseus lipoma is difficult. Radiologists frequently diagnose an intraosseus lipoma, whereas histology shows the classical signs of a solitary bone cyst. We present 12 cases of a solitary cyst of the calcaneus. MATERIAL AND METHODS: Between 1993 and 2001 we operated on 12 patients (8 men, 4 women, median age 28 +/- 14 years) with calcaneal cysts. 9 patients received a curretage and an autologous, one patient a homologous, one patient a mixed autologous-homologous bone-grafting and one patient only a curretage (due to the small diameter of the cyst) of their cysts. RESULTS: No case revealed the histological picture of a fatty formation, which appears to be typical for an intraosseus lipoma. All of the microscopic findings resembled the characteristics seen in cysts of the long bones. A pathological fracture has not been observed. CONCLUSION: The histologically confirmed calcaneal cysts showed the radiological signs that are supposed to be typical for an intraosseous lipoma. It cannot be decided whether the histologically diagnosed calcaneal lipomas described by others can be interpreted as fatty degeneration of a calcaneal cyst, or whether fatty areas of the bone marrow have given a wrong impression. Since the literature only describes single isolated cases of a pathological fracture of the calcaneal cyst or lipoma, asymptomatic patients should be treated non-operatively.

Differential gene expression in stromal cells of human giant cell tumor of bone.

Giant cell tumor (GCT) offers a unique model for the hematopoietic-stromal cell interaction in human bone marrow. Evidence has been presented that GCT stromal cells (GCTSCs) promote accumulation, size and activity of the giant cells. Although GCTSCs are considered the neoplastic component of GCT, little is known about their genetic basis and, to date, a tumor-specific gene expression pattern has not been characterized. Mesenchymal stem cells (MSCs) have been identified as the origin of the GCT neoplastic stromal cell. Using state of the art array technology, expression profiling was applied to enriched stromal cell populations from five different GCTs and two primary MSCs as controls. Of the 29 differentially expressed genes found, 25 showed an increased expression. Differential mRNA expression was verified by real-time polymerase chain reaction analysis of 10 selected genes, supporting the validity of cDNA arrays as a tool to identify tumor-related genes in GCTSCs. Increased expression of two oncogenes, JUN and NME2, was substantiated at the protein level, utilizing immunohistochemical evaluation of GCT sections and Western-blot analysis. Increased phosphorylation of JUN Ser-63 was also found.