Distal Fibular Metastasis of Colorectal Carcinoma: A Case Report

Case

A 62-year-old woman presenting with ankle pain was initially treated for a non-displaced fracture. Persistent pain despite months of conservative management for her presumed injury prompted repeat radiographs which demonstrated the progression of a lytic lesion and led to an orthopedic oncology referral. Following a complete work-up, including biopsy and staging, she was diagnosed with colorectal carcinoma metastatic to the distal fibula.

Conclusion

Secondary tumors of the fibula are uncommon but an important diagnosis to consider for intractable lower extremity pain especially in patients with history of malignancy or lack of age-appropriate cancer screening.

How do US orthopaedic surgeons view placebo-controlled surgical trials? A pilot online survey study

Randomised placebo-controlled trials (RPCTs) are the gold standard for evaluating novel treatments. However, this design is rarely used in the context of orthopaedic interventions where participants are assigned to a real or placebo surgery. The present study examines attitudes towards RPCTs for orthopaedic surgery among 687 orthopaedic surgeons across the USA. When presented with a vignette describing an RPCT for orthopaedic surgery, 52.3% of participants viewed it as 'completely' or 'mostly' unethical. Participants were also asked to rank-order the value of five different types of evidence supporting the efficacy of a surgery, ranging from RPCT to an anecdotal report. Responses regarding RPCTs were polarised with 26.4% viewing it as the least valuable (even less valuable than an anecdote) and 35.7 .% viewing it as the most valuable. Where equipoise exists, if we want to subject orthopaedic surgeries to the highest standard of evidence (RPCTs) before they are implemented in clinical practice, it will be necessary to educate physicians on the value and ethics of placebo surgery control conditions. Otherwise, invasive procedures may be performed without any benefits beyond possible placebo effects.

Human osteoarthritis cartilage-derived stromal cells activate joint degeneration through TGF-beta lateral signaling

Human osteoarthritis cartilage contains chondrocytes (OAC) and mesenchymal stromal cells (OA-MSC). Here, we found that TGF-β had different effects on OA-MSC and OAC, and revealed its lateral signaling mechanism in OA. RNAseq analysis indicated that OA-MSC expressed the same level of Bone Morphogenetic Protein (BMP) Receptor-1A as OAC but only 1/12 of Transforming Growth Factor beta (TGF-β) Receptor-1. While TGF-β specifically activated SMAD2 in OAC, it also activated BMP signaling-associated SMAD1 in OA-MSC. While TGF-β stimulated chondrogenesis in OAC, it induced hypertrophy, mineralization, and MMP-13 in OA-MSC. Inhibiting TGF-βR1 suppressed MMP-13 in OA-MSC but stimulated it in OAC. In contrast, by specifically targeting BMPR1A/ACVR1 in both cell types, LDN193189 inhibits cartilage degeneration through suppressing hypertrophy and MMP-13 in a mouse osteoarthritis model. Thus, LDN193189, a drug under development to inhibit constitutive BMP signaling during heterotopic ossification, may be re-purposed for OA treatment.

Anti-miRNA Oligonucleotide Therapy for Chondrosarcoma

Chondrosarcoma is a highly aggressive primary malignant bone tumor mostly occurring in adults. There are no effective systemic treatments, and patients with this disease have poor survival. miR-181a is an oncomiR that is overexpressed in high-grade chondrosarcoma and promotes tumor progression. Regulator of G-protein signaling 16 (RGS16) is a target of miR-181a. Inhibition of RGS16 expression by miR-181a enhances CXC chemokine receptor 4 signaling, which in turn increases MMP1 and VEGF expression, angiogenesis, and metastasis. Here, we report the results of systemic treatment with anti-miRNA oligonucleotides (AMO) directed against miR-181a utilizing a nanopiece delivery platform (NPs). NPs were combined with a molecular beacon or anti-miR-181a oligonucleotides and are shown to transfect chondrosarcoma cells in vitro and in vivo Intratumoral injection and systemic delivery had similar effects on miR-181a expression in nude mice bearing chondrosarcoma xenografts. Systemic delivery of NPs carrying anti-miR-181a also restored RGS16 expression, decreased expression of VEGF and MMP1, MMP activity, and tumor volume by 32% at day 38, and prolonged survival from 23% to 45%. In conclusion, these data support that systemic delivery of AMO shows promise for chondrosarcoma treatment.

Does CT-based Rigidity Analysis Influence Clinical Decision-making in Simulations of Metastatic Bone Disease?

BACKGROUND

There is a need to improve the prediction of fracture risk for patients with metastatic bone disease. CT-based rigidity analysis (CTRA) is a sensitive and specific method, yet its influence on clinical decision-making has never been quantified.

QUESTIONS/PURPOSES

What is the influence of CTRA on providers' perceived risk of fracture? (2) What is the influence of CTRA on providers' treatment recommendations in simulated clinical scenarios of metastatic bone disease of the femur? (3) Does CTRA improve interobserver agreement regarding treatment recommendations?

METHODS

We conducted a survey among 80 academic physicians (orthopaedic oncologists, musculoskeletal radiologists, and radiation oncologists) using simulated vignettes of femoral lesions presented as three separate scenarios: (1) no CTRA input (baseline); (2) CTRA input suggesting increased risk of fracture (CTRA+); and (3) CTRA input suggesting decreased risk of fracture (CTRA-). Participants were asked to rate the patient's risk of fracture on a scale of 0% to 100% and to provide a treatment recommendation. Overall response rate was 62.5% (50 of 80).

RESULTS

When CTRA suggested an increased risk of fracture, physicians perceived the fracture risk to be slightly greater (37% ± 3% versus 42% ± 3%, p < 0.001; mean difference [95% confidence interval {CI}] = 5% [4.7%-5.2%]) and were more prone to recommend surgical stabilization (46% ± 9% versus 54% ± 9%, p < 0.001; mean difference [95% CI] = 9% [7.9-10.1]). When CTRA suggested a decreased risk of fracture, physicians perceived the risk to be slightly decreased (37% ± 25% versus 35% ± 25%, p = 0.04; mean difference [95% CI] = 2% [2.74%-2.26%]) and were less prone to recommend surgical stabilization (46% ± 9% versus 42% ± 9%, p < 0.03; mean difference [95% CI] = 4% [3.9-5.1]). The effect size of the influence of CTRA on physicians' perception of fracture risk and treatment planning varied with lesion severity and specialty of the responders. CTRA did not increase interobserver agreement regarding treatment recommendations when compared with the baseline scenario (κ = 0.41 versus κ = 0.43, respectively).

CONCLUSIONS

Based on this survey study, CTRA had a small influence on perceived fracture risk and treatment recommendations and did not increase interobserver agreement. Further work is required to properly introduce this technique to physicians involved in the care of patients with metastatic lesions. Given the number of preclinical and clinical studies outlining the efficacy of this technique, better education through presentations at seminars/webinars and symposia will be the first step. This should be followed by clinical trials to establish CTRA-based clinical guidelines based on evidence-based medicine. Increased exposure of clinicians to CTRA, including its underlying methodology to study bone structural characteristics, may establish CTRA as a uniform guideline to assess fracture risk.

LEVEL OF EVIDENCE

Level III, economic and decision analyses.

CT-based Structural Rigidity Analysis Is More Accurate Than Mirels Scoring for Fracture Prediction in Metastatic Femoral Lesions

BACKGROUND

Controversy continues regarding the appropriate assessment of fracture risk in long bone lesions affected by disseminated malignancy.

QUESTIONS/PURPOSES

The purpose of this ongoing Musculoskeletal Tumor Society-sponsored, multi-institutional prospective cross-sectional clinical study is to compare CT-based structural rigidity analysis (CTRA) with physician-derived Mirels scoring for predicting pathologic fracture in femoral bone lesions. We hypothesized CTRA would be superior to Mirels in predicting fracture risk within the first year based on (1) sensitivity, specificity, positive predictive value, and negative predictive value; (2) receiver operator characteristic (ROC) analysis; and (3) fracture prediction after controlling for potential confounding variables such as age and lesion size.

METHODS

Consented patients with femoral metastatic lesions were assigned Mirels scores by the individual enrolling orthopaedic oncologist based on plain radiographs and then underwent CT scans of both femurs with a phantom of known density. The CTRA was then performed. Between 2004 and 2008, six study centers performed CTRA on 125 patients. The general indications for this test were femoral metastatic lesions potentially at risk of fracture. The enrolling physician was allowed the choice of prophylactic stabilization or nonsurgical treatment, and the local treating oncology team along with the patient made this decision. Of those 125 patients, 78 (62%) did not undergo prophylactic stabilization and had followup sufficient for inclusion, which was fracture through the lesion within 12 months of CTRA, death within 12 months of CTRA, or 12-month survival after CTRA without fracture, whereas 15 (12%) were lost to followup and could not be studied here. The mean patient age was 61 years (SD, 14 years). There were 46 women. Sixty-four of the lesions were located in the proximal femur, 13 were in the diaphysis, and four were distal. Osteolytic lesions prevailed (48 lesions) over mixed (31 lesions) and osteoblastic (15 lesions). The most common primary cancers were breast (25 lesions), lung (14 lesions), and myeloma (11 lesions). CTRA was compared with Mirels based on sensitivity/specificity analysis, ROC, and fracture prediction by multivariate analysis. For the CTRA, reduction greater than 35% in axial, bending, or torsional rigidities at the lesion was considered at risk for fracture, whereas a Mirels score of 9 or above, as suggested in the original manuscript, was used as the definition of impending fracture.

RESULTS

CTRA provided higher sensitivity (100% versus 66.7%), specificity (60.6% versus 47.9%), positive predictive value (17.6% versus 9.8%), and negative predictive value (100% versus 94.4%) compared with the classic Mirels definition of impending fracture (≥ 9), although there was considerable overlap in the confidence intervals. ROC curve analysis found CTRA to be better than the Mirels score regardless of what Mirels score cutoff was used. After controlling for potential confounding variables including age, lesion size, and Mirels scores, multivariable logistic regression indicated that CTRA was a better predictor of fracture (likelihood ratio test = 10.49, p < 0.001).

CONCLUSIONS

CT-based structural rigidity analysis is better than Mirels score in predicting femoral impending pathologic fracture. CTRA appears to provide a substantial advance in the accuracy of predicting pathological femur fracture over currently used clinical and radiographic criteria.

LEVEL OF EVIDENCE

Level III, diagnostic study.

miR-181a Targets RGS16 to Promote Chondrosarcoma Growth, Angiogenesis, and Metastasis

Chondrosarcoma is the most common primary malignant bone tumor in adults, has no effective systemic treatment, and patients with this disease have poor survival. Altered expression of microRNA (miR) is involved in tumorigenesis; however, its role in chondrosarcoma is undetermined. miR-181a is overexpressed in high-grade chondrosarcoma, is upregulated by hypoxia, and increases VEGF expression. Here, the purpose was to determine the mechanism of miR-181a regulation of VEGF, determine whether miR-181a overexpression promotes tumor progression, and to evaluate an antagomir-based approach for chondrosarcoma treatment. Therapeutic inhibition of miR-181a decreased expression of VEGF and MMP1 in vitro, and angiogenesis, MMP1 activity, tumor growth, and lung metastasis, all by more than 50%, in a xenograft mouse model. A target of miR-181a is a regulator of G-protein signaling 16 (RGS16), a negative regulator of CXC chemokine receptor 4 (CXCR4) signaling. CXCR4 signaling is increased in chondrosarcoma, its expression is also increased by hypoxia, and is associated with angiogenesis and metastasis; however, receptor blockade is only partially effective. RGS16 expression is restored after miR-181a inhibition and partially accounts for the antiangiogenic and antimetastatic effects of miR-181a inhibition. These data establish miR-181a as an oncomiR that promotes chondrosarcoma progression through a new mechanism involving enhancement of CXCR4 signaling by inhibition of RGS16.

IMPLICATIONS

Targeting miR-181a can inhibit tumor angiogenesis, growth, and metastasis, thus suggesting the possibility of antagomir-based therapy in chondrosarcoma.

MicroRNA regulates vascular endothelial growth factor expression in chondrosarcoma cells

BACKGROUND

Systemic treatments to prevent or treat chondrosarcoma metastasis are lacking and targeted therapy has yet to be developed. Hypoxia develops in tumors as they grow and hypoxia-related alterations in gene expression underlie some of the traits of cancer. One critical trait is the ability to induce sustained angiogenesis, which is usually related to expression of vascular endothelial growth factor (VEGF). A potential hypoxia-related mechanism resulting in altered gene expression involves microRNA. Little is known about microRNA expression in chondrosarcoma and its potential role in regulation of VEGF expression.

QUESTIONS/PURPOSES

Our purposes were (1) to determine if there is hypoxia-regulated microRNA overexpressed in chondrosarcoma; (2) if that contributes to increased VEGF expression; and (3) can VEGF expression be inhibited with a specific antagomir?

METHODS

MicroRNA expression was analyzed in two primary human chondrosarcomas and articular cartilage using array analysis and a cutoff of a fourfold difference in expression between tumor and normal tissue. The effects of hypoxia and hypoxia-inducible factor-1α (HIF-1α) transfection and silencing with siRNA on expression of candidate microRNAs were analyzed in chondrosarcoma cell line JJ. VEGF expression was measured with quantitative polymerase chain reaction and enzyme-linked immunosorbent assay after specific microRNA transfection and knockdown.

RESULTS

miR-181a was identified by array analysis and confirmed with quantitative reverse transcription-polymerase chain reaction, which showed that miR-181a was overexpressed in both human chondrosarcomas (33- and 55-fold) and the JJ cell line (sixfold) compared with cartilage and chondrocytes, respectively. In vitro, hypoxia and HIF-1α transfection each further increased miR-181a expression twofold in JJ cells. miR-181a transfection of JJ cells doubled expression of VEGF mRNA and increased secreted VEGF protein by 46% in normoxia, an effect that could be either direct or indirect. Similar enhancement of VEGF expression by miR-181a was found during hypoxia. Transfection with the antagomir anti-miR-181a decreased VEGF protein by 27% in normoxia and 23% in hypoxia.

CONCLUSIONS

miR-181a is a hypoxia-regulated microRNA that is overexpressed in chondrosarcoma and enhances VEGF expression, an effect that could be inhibited by anti-miR-181a.

CLINICAL RELEVANCE

Systemic treatment options for chondrosarcoma are limited. Antiangiogenic strategies could potentially be effective in limiting tumor progression. One method of inhibiting VEGF expression and associated angiogenesis could be an antagomir-based therapy targeted at miR-181a or other oncogenic microRNAs, although methods of systemic delivery are still under development. The effectiveness of antagomirs also needs to be compared with other antiangiogenic modalities in preclinical models.

Treatment Planning and Fracture Prediction in Patients with Skeletal Metastasis with CT-Based Rigidity Analysis

PURPOSE

Pathologic fractures could be prevented if reliable methods of fracture risk assessment were available. A multicenter prospective study was conducted to identify significant predictors of physicians' treatment plan for skeletal metastasis based on clinical fracture risk assessments and the proposed CT-based Rigidity Analysis (CTRA).

EXPERIMENTAL DESIGN

Orthopedic oncologists selected a treatment plan for 124 patients with 149 metastatic lesions based on the Mirels method. Then, CTRA was performed, and the results were provided to the physicians, who were asked to reassess their treatment plan. The pre- and post-CTRA treatment plans were compared to identify cases in which the treatment plan was changed based on the CTRA report. Patients were followed for a 4-month period to establish the incidence of pathologic fractures.

RESULTS

Pain, lesion type, and lesion size were significant predictors of the pre-CTRA plan. After providing the CTRA results, physicians changed their plan for 36 patients. CTRA results, pain, and primary source of metastasis were significant predictors of the post-CTRA plan. Follow-up of patients who did not undergo fixation resulted in 7 fractures; CTRA predicted these fractures with 100% sensitivity and 90% specificity, whereas the Mirels method was 71% sensitive and 50% specific.

CONCLUSIONS

Lesion type and size and pain level influenced the physicians' plans for the management of metastatic lesions. Physicians' treatment plans and fracture risk predictions were significantly influenced by the availability of CTRA results. Due to its high sensitivity and specificity, CTRA could potentially be used as a screening method for pathologic fractures.

CXCR4-targeted therapy inhibits VEGF expression and chondrosarcoma angiogenesis and metastasis

Chondrosarcoma is notable for its lack of response to conventional cytotoxic chemotherapy, propensity for developing lung metastases, and poor survival. Therefore, a better understanding of angiogenic and metastatic pathways is needed. Multiple pathways regulate angiogenesis and metastasis, including chemokines and their receptors. In this study, we investigated chemokine (C-X-C motif) receptor 4 (CXCR4) signaling in chondrosarcoma and tested the hypotheses that CXCR4 inhibition suppresses tumor angiogenesis and metastasis. CXCR4 expression, analyzed by real-time PCR and Western blot, was increased in human chondrosarcoma cell line JJ compared with normal chondrocytes and was further increased in JJ by hypoxia (2% O2), vascular endothelial growth factor A (VEGFA; 10 ng/mL), and in xenograft tumors in nude mice. The CXCR4 ligand CXCL12 (10 ng/mL) doubled secreted VEGFA, measured with ELISA, under hypoxic conditions and this conditioned media increased human umbilical vein endothelial cell tube formation. These effects were inhibited by CXCR4 siRNA or AMD3100 (5 μg/mL). In a xenograft mouse model, four weeks of AMD3100 treatment (1.25 mg/kg, intraperitoneally twice daily) inhibited tumor angiogenesis, tumor growth, and metastasis. VEGFA content in tumor extracts was decreased (7.19 ± 0.52 ng/mL control vs. 3.96 ± 0.66 treatment) and bioimaging of angiogenesis was decreased by 56%. Tumor volumes averaged 4.44 ± 0.68 cm(3) in control compared with 2.48 ± 0.61 cm(3) in the treatment group. The number of lung metastatic nodules was 23 ± 9 in control compared with 10 ± 6 in the treatment group (N = 8/group). Therefore, CXCR4-targeted therapy may be a treatment strategy for chondrosarcoma.

Locking buttons increase fatigue life of locking plates in a segmental bone defect model

BACKGROUND

Durability of plate fixation is important in delayed union. Although locking plates result in stronger constructs, it is not known if locking affects the fatigue life of a plate. Two locking screws on either side of the nonunion could decrease working length and increase strain in the plate. However, the reinforcing effect of the locking head on the plate may compensate, so that it is unclear whether locking reduces fatigue life.

QUESTIONS/PURPOSES

We determined whether locking screws, compression screws, and locking buttons reduce or increase the fatigue life of a plate.

METHODS

We tested fatigue life of four constructs using an eight-hole locking plate in a segmental defect model: (1) all locking screws (Locked; n = 5); (2) all compression screws (Unlocked; n = 5); (3) six compression screws with two locking buttons in the central holes (Button; n = 6); and (4) six compression screws with two open central holes (Open; n = 6).

RESULTS

The Button group had the longest fatigue life (1.3 million cycles). There was no difference between the Locked and Unlocked groups. All of the constructs failed by fracture of the plates through a screw hole adjacent to the defect.

CONCLUSIONS

Locking screws did not improve fatigue life, however a locking button increased the fatigue life of a locking plate in a segmental bone defect model.

CLINICAL RELEVANCE

Locking buttons in holes adjacent to a defect may improve durability, which is important when delayed union is a possibility.

CXCR4/SDF1 mediate hypoxia induced chondrosarcoma cell invasion through ERK signaling and increased MMP1 expression

Background

Chondrosarcoma is a disease that does not respond to conventional cytotoxic chemotherapy and expression of MMP1 is a marker for a poor prognosis. The mechanism of increased MMP1 expression in chondrosarcoma is not completely known. Our goal is to identify molecular pathways that could serve as therapeutic targets. Chondrosarcoma become hypoxic as they grow, are capable of eliciting an angiogenic response, and typically metastasize to the lungs. The present study determined the effect of hypoxia and specifically HIF-1a on expression of CXCR4 and MMP1 and their role in chondrosarcoma cell invasion.

Results

CXCR4 and its ligand, SDF1, are upregulated in primary chondrosarcoma tumors compared to normal articular cartilage, and CXCR4 was upregulated in chondrosarcoma cell line JJ compared to normal chondrocytes. Hypoxia and specifically HIF-1a increased CXCR4 and MMP1 expression in JJ cell line and chondrosarcoma invasion in vitro. The hypoxia mediated increase in MMP1 expression and chondrosarcoma invasion could be inhibited by siRNA directed at HIF-1a or CXCR4, the CXCR4 inhibitor AMD3100, as well as with ERK inhibitor U0126 and ERK siRNA.

Conclusions

Chondrosarcoma cell invasion is increased by hypoxia induced expression of CXCR4 and MMP1 and is mediated by HIF-1a and ERK. Both invasion and MMP1 can be inhibited with CXCR4 blockade, suggesting that CXCR4/SDF1 signaling may be a therapeutic target for chondrosarcoma.

HDAC4 represses vascular endothelial growth factor expression in chondrosarcoma by modulating RUNX2 activity

Chondrosarcoma is a primary bone tumor with a dismal prognosis; most patients with this disease develop fatal pulmonary metastases, suggesting the need for a better systemic treatment. Anti-angiogenesis treatment may be useful, because angiogenesis is critical for both tumor growth and metastasis. Vascular endothelial growth factor (VEGF) is the most potent pro-angiogenic factor and is regulated by pathways related to the normal physiologic response to hypoxia and genetic alterations related to the malignant phenotype. Our prior work has shown that VEGF is overexpressed in high grade chondrosarcoma and chondrosarcoma cell lines. Working on the premise that developmental pathways giving a selective growth advantage are often recapitulated in tumors, we investigated the regulation of VEGF by HDAC4 and Runx2 in chondrosarcoma. We tested the hypothesis that there is dysregulation of HDAC4/Runx2/VEGF gene expression and that decreased HDAC4 expression accounts for at least some of the increased VEGF expression seen in chondrosarcoma. We show that reduced expression of HDAC4 in chondrosarcoma cells increases expression of Runx2 leading to increased expression of VEGF and in vitro angiogenesis. Thus, both hypoxia and dysregulated expression of a developmental pathway are causes of increased VEGF expression in chondrosarcoma.

11beta-hydroxysteroid dehydrogenase type 1 expression in periprosthetic osteolysis

Periprosthetic membranes contain fibroblasts, macrophages and cytokines including interleukin 1Beta (IL-1Beta) and tumor necrosis factor alpha (TNF-alpha). Glucocorticoids may play an inhibitory role in osteolysis through the upregulation of 11Beta-hydroxysteroid dehydrogenase type 1 (11Beta-HSD1) in membrane fibroblasts by IL-1Beta and TNF-alpha. This study evaluated 15 periprosthetic membranes for the presence of 11Beta-HSD1 using immunochemistry. Also, fibroblast cell cultures were exposed to IL-1Beta and TNF-alpha, and 11Beta-HSD1 gene expression was evaluated. In all membranes, 11Beta-HSD1was present, and fibroblast 11Beta-HSD1 was upregulated significantly after the addition of IL-1Beta and TNF-alpha. These findings suggest increased 11Beta-HSD1 expression in fibroblasts may be a mechanism for increasing local cortisol levels in membranes, which could potentiate the osteolytic process through inhibition of osteoblastic function.

Lysis of human chondrosarcoma cells by cytolytic T lymphocytes recognizing a MAGE-A3 antigen presented by HLA-A1 molecules

Treatment of chondrosarcomas is limited to resection because these tumors are unresponsive to standard adjuvant treatments, such as chemotherapy and radiation. We have previously shown that high-grade chondrosarcomas express unspecified members of the Melanoma Antigen (MAGE) gene family. We show here that FS human chondrosarcoma (FS) cells express MAGE-A3 gene and HLA-A1 molecules. In vitro assays show that a cytolytic T-lymphocyte clone (CTL) specific for a MAGE-A3 peptide presented by HLA-A1 specifically lysed FS chondrosarcoma cells. Addition of antigenic peptide did not increase the susceptibility of FS cells to CTL mediated lysis, suggesting that HLA-A1 expression by the chondrosarcoma cells limited their susceptibility to lysis by the anti-MAGE-A3 CTL clone. Incubation of FS cells with 50 U/mL interferon-gamma increased surface expression of HLA class-I molecules, increased their susceptibility to lysis, and had no effect on MAGE-A3 gene expression. These results suggest that immunotherapy targeted against chondrosarcoma cells is possible.

Recent advances in the basic science of chondrosarcoma

Chondrosarcoma are a heterogeneous group of tumors whose treatment is limited to surgical removal. Molecular genetic analysis of these tumors has revealed some of the abnormalities responsible for the traits of the malignant phenotype.

Pathologic neovascularization in cartilage tumors

Tumor-induced angiogenesis is necessary to sustain radial growth of tumors. Increased microvascularity has been correlated with increased metastatic potential in breast, gastrointestinal, and gynecologic tumors, but has not been well studied in cartilaginous tumors. Grade II and Grade III chondrosarcomas have increased metastatic potential compared with Grade I tumors. One reason for this may be pathologic neovascularization. The purpose of the current study was to quantify the microvessel density of cartilage tumors. Seven Grade III, 17 Grade II, and eight Grade I chondrosarcomas, and 22 benign cartilage tumors were examined. Specimens were stained with antiCD34 antibody. Microvessel densities then were determined by direct counting and estimated using the Chalkley technique. Microvessel densities for Grade III and Grade II chondrosarcomas were 45.9 and 46.2 per high-power field and for Grade I and benign tumors the microvessel densities were 9.3 and 10.3. Microvessel densities of the aggressive tumors (Grades III and II) were greater than the microvessel densities of the nonaggressive tumors (Grade I and benign). Chalkley estimates confirmed the results. Microvascularity in cartilage tumors correlates with their biologic aggressiveness and seems promising as a variable to help with histopathologic grading and as a target for new treatment modalities.

Angiogenic cytokines in cartilage tumors

Pathologic neovascularization has been described in numerous types of cancers. The angiogenic cytokines vascular endothelial growth factor and basic fibroblast growth factor are thought to be the primary inducers of angiogenesis in these tumors. Hypoxia-inducible transcription factor is a nuclear transcription factor that promotes vascular endothelial growth factor expression. Prior studies have shown pathologic neovascularization in chondrosarcoma, which correlates with pathologic grade of the tumor. Angiogenic and nonangiogenic cartilage tumors were studied for expression of vascular endothelial growth factor, basic fibroblast growth factor and hypoxia-inducible transcription factors by immunohistochemistry and Northern blot analysis. Expression of vascular endothelial growth factor and hypoxia-inducible transcription factor were increased significantly in angiogenic tumors. Fibroblast growth factor expression was similar in angiogenic and nonangiogenic specimens. This may have implications for tumor grading and surgical decision-making, and potential treatment with antiangiogenesis chemotherapeutic agents.

PTEN mutation is rare in chondrosarcoma

Chondrosarcoma is the second most common primary malignant neoplasm of bone in adults, but the major genetic events involved in the progression of this often-fatal cancer remain to be elucidated. Loss of heterozygosity of chromosome 10q has been reported in 67% of chondrosarcoma. The tumor suppressor gene PTEN is located on chromosome 10q, specifically 10q23, raising the possibility that the loss of PTEN function is responsible for some chondrosarcomas. The authors examined 40 chondrosarcoma tumors and tumor-derived cell lines for alterations in PTEN. Only one mutation resulting in a truncated PTEN protein was detected, which was in a metastasized extraskeletal myxoid chondrosarcoma. Thus, mutated PTEN is an uncommon event in the development of chondrosarcoma. The high frequency of loss of heterozygosity on 10q suggests the presence of additional tumor suppressor genes at these loci.

Cancer/testis antigen CSAGE is concurrently expressed with MAGE in chondrosarcoma

Differential display-polymerase chain reaction was used to compare gene expression between human chondrosarcoma cell lines and normal cartilage. A new gene, CSAGE, has been cloned and belongs to a gene family that includes the taxol resistance associated gene (TRAG)-3. CSAGE, like TRAG-3, does not confer resistance to taxol when transfected in vitro. Both genes have alternatively spliced variants. CSAGE and TRAG-3 are expressed in chondrosarcoma, melanoma, and cartilage and testis, but not in other normal tissues. TRAG-3 has been reported to be a cancer/testis antigen. Our results suggest that CSAGE belongs to the growing list of cancer/testis antigens as well. In all of the CSAGE positive samples, the melanoma antigen gene family was also expressed. This is the first report on the expression of cancer/testis antigens in chondrosarcoma.

Gadolinium inhibits thymidine incorporation and induces apoptosis in chondrocytes

Magnetic resonance arthrography. a procedure where contrast agents containing gadolinium are administered intra-articularly, has become a useful tool in musculoskeletal diagnosis. Although considered safe for systemic use, toxicities in some tissues have been identified for both free gadolinium ion and the gadolinium chelates used as contrast. In this study, the effects of short-term exposure of articular chondrocytes to gadolinium contrast were examined by assaying for proteoglycan synthesis, cell proliferation, and apoptosis. Bovine chondrocytes were grown in monolayer culture and exposed to gadodiamide for 16 h. Proteoglycan synthesis was measured through incorporation of radiolabeled sulfate. Uptake of radiolabeled thymidine assessed cell proliferation. Apoptosis was detected using the TUNEL assay, where DNA strand breaks characteristic of apoptosis are labeled with fluorescent nucleotide. Proteoglycan synthesis was stimulated by lower dose exposure to gadodiamide. At higher doses, proteoglycan synthesis returned to baseline. Cell proliferation decreased following exposure to gadodiamide in a dose-dependent manner. Chondrocyte apoptosis was induced in a dose-dependent manner. Further work is needed to determine if these in vitro effects are present in the intact joint.

The role of preoperative chemotherapy in the treatment of infantile fibrosarcoma

Infantile fibrosarcoma (IFS) is a rare tumor most often affecting the extremities of infants and young children. Unlike its adult counterpart, IFS has a low potential for metastatic spread, and surgical extirpation alone has therefore resulted in an excellent prognosis. The amputation rate, however, exceeds 50%. The dramatic response in 2 recent cases to preoperative chemotherapy, given in an attempt to avoid amputation, prompted this report and a review of the literature.

Multidrug resistance-1 and p-glycoprotein in human chondrosarcoma cell lines: expression correlates with decreased intracellular doxorubicin and in vitro chemoresistance

We report on two chondrosarcoma cell lines, FS and AQ, that may be used as models of multidrug resistance in chondrosarcoma. Multidrug resistance-1 expression was assayed with reverse transcription-polymerase chain reaction. Immunostaining for the multidrug resistance-1 product, P-glycoprotein, was performed with the monoclonal antibody C494. Intracellular levels of doxorubicin were measured by fluorescent emission at 590 nm after 1 hour of incubation with the agent and again after 1, 2, and 4-hour washout periods. Chemosensitivity was assayed by staining micropellet cultures of AQ and FS cells with fluorescein acetate before and after the cells were exposed to varying doses of doxorubicin for 48 hours. Cytotoxicity was assessed by comparison of computer-processed images before and after treatment. The FS cell line was positive for multidrug resistance-1 expression, stained heavily for P-glycoprotein, and had significantly lower intracellular levels of doxorubicin than the AQ cell line, which was negative for multidrug resistance-1 and P-glycoprotein. Chemosensitivity testing showed that the FS cell line was significantly more resistant to doxorubicin than was the AQ cell line at all doses tested. Our results show that multidrug resistance-1 expression in a human chondrosarcoma cell line results in resistance to doxorubicin in vitro.

Chemotherapy and P-glycoprotein expression in chondrosarcoma

Chondrosarcomas are alleged to be resistant to chemotherapy. A retrospective review of our experience primarily with dedifferentiated chondrosarcomas treated with chemotherapy was performed to reevaluate the efficacy of chemotherapy for this tumor. There were 18 patients: 14 stage IIB and four stage III. Seventeen patients had dedifferentiated chondrosarcoma. The median age at diagnosis was 57 years. Fourteen of the patients underwent wide excision of the tumor, two underwent amputation, and two had no surgery. The femur and the pelvis were the most common locations of the primary tumor. Chemotherapy for 11 of the patients consisted of cisplatin and doxorubicin. Survival was analyzed with the Kaplan-Meier method; the median survival was 12 months. The hypothesis that chondrosarcomas express P-glycoprotein was tested. Expression of P-glycoprotein was evaluated by immunostaining with use of the C494 and C219 antibodies on 41 benign and malignant cartilage tumors, six of which were from the patients in the chemotherapy group. Immunostaining revealed that 37 of 41 cartilage tumors expressed P-glycoprotein. The rate of survival of patients with high-grade chondrosarcoma treated with chemotherapy is poor. P-glycoprotein expression is common in benign and malignant cartilage lesions. The lack of response to chemotherapy may be related to the expression of P-glycoprotein.

Long bone surface osteomas: imaging features that may help avoid unnecessary biopsies

OBJECTIVE

Our purpose is to show that a combination of imaging techniques and periodic radiologic follow-up offers an alternative to biopsy in certain patients with long bone surface osteomas.

CONCLUSION

Asymptomatic lesions that are consistent with osteoma on a combination of imaging studies can be followed up clinically and radiographically, allowing patients to avoid unnecessary biopsies.

p53 mutations in chondrosarcoma

Chondrosarcoma is a primary bone tumor that has several different grades and variants. We evaluated 48 chondrosarcomas for p53 overexpression and p53 mutations. p53 expression was evaluated with immunohistochemistry using monoclonal antibodies PAb421, PAb1801, and PAb240. p53 mutations were identified with single-strand conformational polymorphism (SSCP) and DNA sequencing in selected cases. Immunohistochemistry revealed nuclear staining with PAb421 and PAb1801 in the spindle cell portion of one dedifferentiated chondrosarcoma. SSCP analysis was abnormal only in the case with positive immunostaining and localized the mutation to exons 7 and 8. DNA sequence analysis identified a point mutation of G to C in codon 276, resulting in an amino acid substitution of proline for alanine. This point mutation has been reported previously in other tumors but not in chondrosarcoma. Assimilation of our results with previous studies suggests that p53 mutations are present in a minority of chondrosarcomas but when present, are in higher grade chondrosarcomas and their variants.

Sarcoma of bone

Multiagent chemotherapy and limb salvage surgery are two major advances which have occurred over the last twenty years in the treatment of primary bone sarcoma. Limb salvage as an alternative to amputation results in improved quality of life without a compromise in cure. The complications of limb salvage continue to decrease while the durability of the reconstructions continues to improve. Chemotherapy has dramatically improved long-term survival, particularly in children.

Treatment of femoral Ewing's sarcoma

BACKGROUND

The treatment of Ewing's sarcoma consists of chemotherapy for systemic and local disease. However, the role of radiation therapy, and/or surgical resection for definitive local treatment has yet to be determined.

METHODS

A retrospective review of 32 patients (24 males and 8 females) treated for femoral Ewing's sarcoma between 1970 and 1985 was performed. Patients were divided into 3 treatment groups: chemotherapy and radiotherapy (CR) (10); chemotherapy and surgery (CS) (9); and chemotherapy, surgery, and radiotherapy (CSR) (13). Patients in the CR group received a mean of 5320 centigray (cGy) of radiation and patients in the CSR group received a mean of 3590 cGy. Multiagent cyclophosphamide/doxorubicin based chemotherapy was used in all cases. Surgery consisted of wide resection or amputation.

RESULTS

Patients in the CR group had a higher risk of local recurrence than patients in the CS and CSR groups (P=0.02, log rank). The combination of local recurrences and treatment complications necessitated surgery for 7 of 10 CR patients, whereas 1 of 9 and 4 of 13 in the CS and CSR groups required additional surgery. The median survival for the entire group was 39 months. Minimum follow-up for surviving patients was 45 months. Five-year survival consisted of 1 of 10 patients in the CR group, 2 of 9 in the CS group, and 7 of 13 in the CSR group. There were no statistically significant differences among the three survival curves. Tumor location within the femur was a significant prognostic variable. Distal femoral location had a survival advantage compared with proximal and mid-femur locations (P = 0.049, log rank).

CONCLUSIONS

Femoral Ewing's sarcoma remains a disease with a poor prognosis. Radiation alone for local treatment results in a high rate of local recurrence and complications. Our current local treatment strategy for femoral Ewing's sarcoma includes surgery in all and adjuvant radiotherapy in many of the patients.

Soft-tissue sarcomas of the hand and wrist

Treatment of soft-tissue sarcomas of the hand cause the ultimate confrontation between oncologic outcome and function. The management of hand sarcomas is based on knowledge of the specific biology and location of each tumor. This article reviews the multimodality management of soft-tissue sarcomas of the hand and wrist.

Treatment of soft-tissue sarcomas of the hand

We studied the clinical features, radiographic and pathological findings, treatment, and results for twenty-three patients who had been managed for a soft-tissue sarcoma of the hand between 1982 and 1990. The ages of the patients ranged from sixteen to seventy-six years (median age, thirty-one years). The most common clinical finding was a small, painless soft-tissue mass. Twenty of the tumors were high-grade, and eighteen were less than five centimeters in diameter. The most common diagnosis was synovial sarcoma, which was identified in eight patients. Leiomyosarcoma, rhabdomyosarcoma, and malignant fibrous histiocytoma developed in three patients each; epithelioid sarcoma, in two patients; and angiosarcoma, liposarcoma, neuroectodermal tumor, and clear-cell sarcoma, in one patient each. Curative wide excision or amputation was attempted in twenty-two patients; the margins were positive for tumor cells in eight, and local recurrence was seen in nine. Of the twenty-three patients, fourteen had survived, without evidence of disease, after a median duration of follow-up of forty-nine months, and nine had died of disease. The median rate of survival did not differ significantly on the basis of the size or grade of the tumor or the use of adjuvant treatment. However, the rate of survival of the patients who had a soft-tissue sarcoma of the hand that was less than five centimeters in diameter was significantly lower (p = 0.0008) than that of 152 patients who had a similar tumor at another site in an extremity.(ABSTRACT TRUNCATED AT 250 WORDS)

The expression of platelet-derived growth-factor gene in Dupuytren contracture

Dupuytren contracture is a disease of the palmar fascia characterized by nodular fibroblastic proliferation; its etiology and pathogenesis are poorly understood. Growth factors are polypeptides that regulate cell growth and differentiation and extracellular matrix production. Platelet-derived growth factor is known to cause fibroblastic proliferation, and it may be involved in the pathogenesis of Dupuytren contracture. The purpose of this study was to determine if the gene for the B chain of platelet-derived growth factor is expressed in Dupuytren contracture. Tissue from patients who had Dupuytren disease was examined immunohistochemically with the 5B5 antibody, which is a marker for fibroblasts. Polymerase chain reaction, gel electrophoresis, Southern blotting, and in situ hybridization were also used to study gene expression in the tissue as well as in normal fascia, A172 cells, and MRC5 cells. Total cellular RNA was extracted from tissue and cells. Polymerase chain reaction was done with oligonucleotide primers complementary to a portion of the platelet-derived growth-factor-B and platelet-derived growth-factor-receptor genes. The platelet-derived growth-factor-B gene was expressed in all six specimens from the patients who had Dupuytren contracture as well as in the A172 cells, but not in the normal fascia lata or the MRC5 cells. These results were confirmed with Southern blotting of the products of the reaction with a platelet-derived growth-factor-B probe. The gene for the platelet-derived growth-factor receptor was expressed by all tissues and cells studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Platelet-derived growth factor in fibrous musculoskeletal disorders: a study of pathologic tissue sections and in vitro primary cell cultures

Despite the great variability in the clinical behavior of fibrous lesions of the musculoskeletal system, they are composed of cytologically similar fibrocytes. Receptors for estrogen or progesterone, or both, are present in some of these lesions and some increase their rate of growth during periods of high levels of sex steroid hormones. The platelet-derived growth factor-B (PDGF-B) proto-oncogene encodes the B chain of PDGF, a mitogen for fibrocytes. Tissue from aggressive fibromatosis, fibrous dysplasia, plantar fibromatosis, and recurrent plantar fibromatosis was analyzed with use of the polymerase chain reaction and in situ hybridization for the expression of PDGF-B and PDGF beta receptor. Cell culture was used to determine if estrogen and progesterone stimulation modulated the expression of PDGF-B. Aggressive fibromatosis, fibrous dysplasia, and recurrent plantar fibromatosis expressed PDGF-B; plantar fibromatosis, normal plantar fascia, normal fascia lata, and mature scar did not. All of the tissues expressed PDGF beta receptor. The level of expression in aggressive fibromatosis and fibrous dysplasia was four times that in the recurrent plantar fibromatosis. Estrogen and progesterone stimulation in aggressive fibromatosis resulted in an increase in the level of expression. Therefore, the detection of PDGF-B may be an adjunct in the pathologic identification of locally invasive lesions. Its production may be a common mechanism leading to a fibroproliferative response through deregulation of the control of growth by both paracrine and autocrine mechanisms.

Tumors of the elbow and forearm

The trend in the treatment of bone and soft tissue sarcomas of the extremities has been away from radical surgery and toward conservative, limb-sparing surgery, a trend that is present throughout other subdisciplines of surgical oncology. Organ-sparing and limb-sparing surgery has been combined with the use of adjuvants to give equivalent local control and in some cases improved survival. This article summarizes the current staging and treatment of bone and soft tissue tumors of the extremities and discusses some of the features that are unique to the elbow and forearm.

Allograft reconstruction after proximal tibial resection for bone tumors. An analysis of function and outcome comparing allograft and prosthetic reconstructions

Seventeen patients (age, 12-63 years; median, 22 years) treated with proximal tibial allografts were identified. Nine cases were intercalary and eight were osteoarticular allografts. Complications, number of operations, and oncologic and functional results were reviewed. The functional results of the allografts were compared with a prior cohort of patients who had endoprosthesis at the same institution by the same surgeons. There were 14 malignant tumors, two benign aggressive tumors, and one sclerosing osteomyelitis mimicking osteosarcoma. Twelve of 17 patients had complications, the most common being fracture, deformity, and infection. Six patients required more than one procedure, and three had amputations after allograft reconstruction. The ultimate function was excellent in three patients, good in seven, fair in six, and poor in one. There were 14 patients with endoprosthetic reconstruction. Wound problems followed by prosthetic loosening were the most common complications. Of the eight patients requiring a second procedure, three had an amputation. Three had excellent, seven good, and four fair functional results at the final evaluation. No patient in either group had a local recurrence. Allograft provides an alternative to endoprosthetic reconstruction; however, the high incidence of complications makes the outcome unpredictable. Allograft or prosthetic reconstruction provides better functional results than amputation without sacrificing oncologic results.

Management of extremity soft-tissue sarcomas

Management of extremity soft-tissue sarcomas requires accurate clinical staging, pathologic diagnosis, surgical resection with a wide margin, and adjuvant radiation therapy for high-grade lesions. Brachytherapy offers a clean benefit in local control for large (> 5 cm) high-grade sarcomas. The role of radiation therapy for small high-grade and all low-grade soft-tissue sarcomas still is being evaluated. Survival is function of histologic grade, age of patient, size and location of the tumor, metastases, and adequacy of the surgical resection. Efficacy of chemotherapy has yet to be proven.

Crankshaft phenomenon in congenital scoliosis: a preliminary report

To determine whether or not the crankshaft phenomenon occurs after spinal fusion in patients with congenital scoliosis, we reviewed 23 curves in 21 patients who were operated on before age 10 years. Operative procedures consisted of various kinds of posterior fusions as well as anterior and posterior hemiepiphyseodeses. Seven of the 23 curves progressed greater than or equal to 10 degrees during the course of follow-up, and six of the seven demonstrated increased rotation and were believed to demonstrate the crankshaft phenomenon. No spines rotated without curve progression. The only statistically predictive factor was length of follow-up. No curve that underwent anterior and posterior hemiepiphyseodeses demonstrated the crankshaft phenomenon. Although the crankshaft phenomenon can occur in young patients operatively treated for congenital scoliosis, apparently it can be prevented by anterior fusion.

Defects of early fracture-healing in experimental diabetes

Diabetes has been implicated as a cause of impaired fracture-healing. To test this hypothesis, we tested the tensile strength of femora from normal rats and from untreated and insulin-treated diabetic rats two weeks after the production of a closed fracture. One week before the fracture, diabetes was induced by administration of streptozotocin (sixty-five milligrams per kilogram of body weight). The concentration of serum glucose increased from 6.1 +/- 0.3 millimoles per liter (110 +/- 5 milligrams per deciliter) in the control animals to 31.1 +/- 0.8 millimoles per liter (560 +/- 15 milligrams per deciliter) in the untreated diabetic animals. After two weeks of healing, fracture callus from the untreated diabetic animals had a 29 per cent decrease in tensile strength and a 50 per cent decrease in stiffness compared with the controls. Treatment of the diabetic animals with insulin resulted in a mean concentration of serum glucose of 14.4 +/- 0.6 millimoles per liter (260 +/- 10 milligrams per deciliter) and restored the tensile strength and stiffness of the callus to a value that was not statistically different from that of the controls. Between the fourth and eleventh days of healing, there was a 50 to 55 per cent decrease in the collagen content of the callus of the untreated diabetic animals compared with the controls. In addition, on the fourth day of healing, DNA content, an indicator of cellularity of the callus, was decreased 40 per cent in the untreated diabetic group. Between the fourth and eleventh days of healing, the collagen-to-DNA ratio, which was determined as an indicator of net collagen synthesis per cell, was decreased 15 to 50 per cent in callus from the untreated diabetic animals.

Excitability and oscillatory afterpotentials in isolated sheep cardiac Purkinje fibers

Oscillatory afterpotentials, or late afterdepolarizations, are one mechanism postulated to cause cardiac arrhythmias and possibly conduction disturbances. We studied excitability by determining strength-interval curves in Purkinje fibers under normal conditions and during the presence of oscillatory afterpotentials induced by cardiac glycoside toxicity. During exposure to acetylstrophanthidin (0.10-0.15 mg/l), the mean resting potential depolarized 5.6 mV and oscillatory afterpotentials of 3-17 mV appeared. Current threshold for evoking action potentials was reduced below control level (e.g., increased excitability) throughout electrical diastole. Associated with oscillatory afterpotentials was a marked biphasic variation in current threshold giving strength-interval curves a characteristic biphasic shape. During the rising phase of the oscillatory afterpotentials, excitability reached a maximum, whereas the minimum increase in excitability occurred during the falling phase of oscillatory afterpotentials. This biphasic change in excitability remained correlated with the oscillatory afterpotentials at different cycle lengths. Results show that during acetylstrophanthidin toxicity excitability is increased throughout electrical diastole, and characteristic time-dependent changes in excitability occur during oscillatory afterpotentials. Time-dependent changes in excitability were detected with both intra- and extracellular stimulation techniques.