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

Phosphaturic mesenchymal tumor, mixed connective tissue variant (PMT-MCT) causes tumor-induced osteomalacia (TIO). Most cases follow a benign clinical course, with rare occurrences of malignant transformation. We report a case of malignant PMT-MCT and review previous malignant cases to identify predictive factors for transformation. A 13-yr-old female, who presented with hypophosphatemic rickets, elevated serum intact fibroblast growth factor 23 (FGF23) levels, and a nodule in the back, received a diagnosis of TIO because of the benign PMT histopathology. After resection of the primary tumor, regular imaging analyses did not indicate any relapse. At 17 years of age, a tumor developed in the left leg and increased in size. The resected tumor showed a histopathology of pleomorphic sarcoma positive for the TP53 mutation. Despite amputation of the affected leg, the patient died due to multiple metastases at 18 years of age. A literature review revealed that 14 out of 15 reported malignant PMT-MCT tumors occurred in adults, and found no predictive factors for malignant transformation and treatment outcome. Changes in size or number of the tumors along with intact FGF23 levels have been considered as the only sign of malignant transformation. This pediatric case report and literature review indicate the need for prolonged regular monitoring for PMT-MCT.

Tyrosine kinase inhibitors (TKI) work against various types of cancer by inhibiting angiogenic signaling. Little is understood about the incidence, characteristics, and risk factors associated with thromboembolism induced by TKI in routine clinical practice. We retrospectively analyzed data derived from 29 patients with thyroid cancer or soft tissue sarcoma (STS) treated with lenvatinib (n=10) and pazopanib (n=19). Eight (arterial n=4; venous n=4) thromboembolic events developed in 6 (20%) patients. Thromboembolisms occurred during a mean of 149 (range, 42–847) days from starting TKI. The primary disease progressed in all patients with thromboembolism. The overall survival durations of patientswith and without improved thromboembolism were 572 [95% confidence interval (CI), 225– 918] and 176 (95% CI, 84–394) days, respectively, which did not significantly differ (P=0.33). Patients with and without improved thromboembolism survived after onset for 122 (95% CI, 71–173) versus 27 (95%CI, 21–42) days (P=0.049), which significantly differed. Univariate analysis and variate selection for multivariate analysis selected a history of thromboembolism as the most powerful risk factor for new thromboembolism. In summary, the frequency of thromboembolism in clinical practice was higher than that in previous clinical trials. Furthermore, a history of thromboembolism was a risk factor for the development of new thromboembolism in patients treated with TKI. Thromboembolism developed particularly as the primary disease progressed. Our findings require validation in a large-scale study.

BackgroundDenosumab is a game-changing drug for giant cell tumor of bone (GCTB); however, its clinical biomarker in terms of post-administration ossification of the tumors has not been elucidated. The aims of this study were to investigate the relationship between Wnt/β-catenin signaling and the ossification of GCTB and to evaluate whether endogenous nuclear β-catenin expression predicted denosumab-induced bone formation in GCTB. MethodsWe established cultures of patient-derived primary GCTB stromal cells (pGCTB-SCs) and assessed the osteoblastic characteristics of pGCTB-SCs using cytochemical staining, optical density method (405 nm), and immunocytochemistry. Several mRNA expressions of osteoblastic markers (ALP, collagen type Ⅰ alpha 1 (COL1A1), integrin-binding sialoprotein (IBSP), runt-related transcription factor2 (RUNX2), and bone gamma-carboxyglutamate protein (BGLAP) was also investigated using quantitative real-time PCR (qRT-PCR) analysis. The impact on nuclear β-catenin translocation (NBT) by differentiation-induction was evaluated using Western blotting and immunocytochemistry. Wnt signaling inhibitor, GGTI-286, and selective Rac1 inhibitor, NSC23766, were added with OGM to evaluate the essential role of NBT. Furthermore, the distribution of endogenous NBT and the relationship with the tumoral ossification were assessed. Its predictability for the ossification in GCTB was also evaluated using a nuclear β-catenin labeling index (NBLI) of clinical samples (n = 86) and quantitative analyses of CT images.ResultspGCTB-SCs significantly expressed the osteoblastic markers with osteogenic medium (OGM) in a time-dependent manner (P < 0.0001, vs. vehicle). NBT was upregulated within 12 hours after OGM treatment. In addition, decreasing NBT by treatment with 40μM GGTI-286 significantly abolished the osteoblastic differentiation of pGCTB-SCs (P < 0.0001, vs. OGM). The selective Rac1 inhibitor, NSC23766, also suppressed the OGM-induced osteoblastic differentiation and NBT in pGCTB-SCs. Furthermore, in GCTB clinical samples, the NBTs were significantly associated with the tumor ossification following denosumab treatment (P = 0.003 for entire and peripheral tumor, and P = 0.02 for intra-tumor of GCTB) as well as endogenous intra-tumoral ossification. ConclusionsIn summary, our findings suggest a close relationship between the NBT and the osteoblastic differentiation of GCTB. Investigations of NBTs in naïve GCTB samples will provide a promising biomarker for predicting the ossification of GCTB following denosumab treatment.

Chondrosarcoma is the second most common malignant bone tumor. It is characterized by low vascularity and an abundant extracellular matrix, which confer these tumors resistance to chemotherapy and radiotherapy. There are currently no effective treatment options for relapsed or dedifferentiated chondrosarcoma, and new targeted therapies need to be identified. Isocitrate dehydrogenase (IDH) mutations, which are detected in ~50% of chondrosarcoma patients, contribute to malignant transformation by catalyzing the production of 2-hydroxyglutarate (2-HG), a competitive inhibitor of α-ketoglutarate-dependent dioxygenases. Mutant IDH inhibitors are therefore potential novel anticancer drugs in IDH mutant tumors. Here, we examined the efficacy of the inhibition of mutant IDH1 as an antitumor approach in chondrosarcoma cells in vitro and in vivo, and investigated the association between the IDH mutation and chondrosarcoma cells. DS-1001b, a novel, orally bioavailable, selective mutant IDH1 inhibitor, impaired the proliferation of chondrosarcoma cells with IDH1 mutations in vitro and in vivo, and decreased 2-HG levels. RNA-seq analysis showed that inhibition of mutant IDH1 promoted chondrocyte differentiation in the conventional chondrosarcoma L835 cell line and caused cell cycle arrest in the dedifferentiated JJ012 cell line. Mutant IDH1-mediated modulation of SOX9 and CDKN1C expression regulated chondrosarcoma tumor progression, and DS-1001b upregulated the expression of these genes via a common mechanism involving the demethylation of H3K9me3. DS-1001b treatment reversed the epigenetic changes caused by aberrant histone modifications. The present data strongly suggest that inhibition of mutant IDH1 is a promising therapeutic approach in chondrosarcoma, particularly for the treatment of relapsed or dedifferentiated chondrosarcoma.

To evaluate the clinical outcome of combination of carbon-ion radiotherapy with separation surgery (CIRT-SS) in patients with primary spinal/paraspinal sarcoma (PSPS) and epidural spinal cord compression (ESCC). CIRT-SS was performed in 11 consecutive patients. Patients treated in the primary and salvage settings were categorized into Group A (n = 8) and Group B (n = 3), respectively. Clinical results and imaging findings were collected, with a particular focus on ESCC grade, treatment-associated adverse events (AEs), and the locoregional control (LRC) rate and overall survival (OS). The median follow-up period from the start of CIRT-SS was 25 months (7–57 months). ESCC was improved by SS in all cases. No patients exhibited radiation-induced myelopathy (RIM), but three developed Grade 3 vertebral compression fracture (VCF) during follow-up. Locoregional recurrences were observed in four patients [Group A: 1 (12.5%), Group B: 3 (100%)]. Over the entire follow-up period, three patients developed distant metastases and two patients died. The 2-year LRC rate and OS were 70% and 80%, respectively. CIRT-SS in the primary setting achieved acceptable LRC and OS without RIM in patients with PSPS and with ESCC. VCF was the most frequent AE associated with CIRT-SS.

Background Soft tissue sarcomas arise in the deep sites of the buttocks and lower extremities. Since a tourniquet is not applied during surgery for soft tissue sarcomas at such sites, excessive intraoperative blood loss may occur. Various devices, including LigaSure™ (Medtronic, Dublin, Ireland), are used as electrothermal bipolar vessel sealers. However, its clinical relevance in soft tissue sarcomas surgery remains unclear. This study aimed to assess the effectiveness of LigaSure™ in soft tissue sarcomas surgery. Methods This study included 168 patients who underwent surgeries for soft tissue sarcomas in the deep sites in the buttocks and lower extremities between January 2004 and March 2018. The primary outcome was intraoperative blood loss, and secondary outcomes were surgery duration, wound complications, perioperative haemoglobin concentrations and intraoperative blood transfusion. To reduce selection biases, propensity score matching was applied. We defined the matched cases wherein LigaSure™ was used as the ‘using group’ and the other matched cases as the ‘non-using group’. Outcomes were compared between both groups. Results From each group, 35 cases were selected using propensity score matching. The intraoperative blood loss was significantly smaller statistically in the using group (181.5 ± 240.4 ml vs. 394.7 ± 547.3 ml, respectively; P = 0.041). The duration of operation was longer in the using group (189.9 ± 97.6 min vs. 140.6 ± 75.7 min, respectively; P = 0.007). There were no significant differences in other outcomes. Conclusion By using LigaSure™ for soft tissue sarcomas occurring in the buttocks and lower extremities, we observed a trade-off between reduced intraoperative blood loss and longer operative time.

Undifferentiated pleomorphic sarcoma (UPS) is a sarcoma with a poor prognosis. A clinical trial, SARC028, revealed that treatment with anti-PD-1 drugs was effective against UPS. Studies have reported that UPS expresses PD-L1, sometimes strongly (≥ 50%). However, the mechanism of PD-L1 expression in UPS has remained unclear. CKLF-like MARVEL transmembrane domain containing 6 (CMTM6) was identified as a novel regulator of PD-L1 expression. The positive relationship between PD-L1 and CMTM6 has been reported in several studies. The aim of this study was thus to examine CMTM6 expression in UPS and evaluate the relationship between PD-L1 and CMTM6 in this disease. Fifty-one primary UPS samples were subjected to CMTM6 and PD-L1 immunostaining. CMTM6 expression was assessed using proportion and intensity scores. CMTM6 gene copy number was also evaluated using a real-time PCR-based copy number assay. We also analyzed the mRNA expression and copy number variation of PD-L1 and CMTM6 in The Cancer Genome Atlas (TCGA) data. TCGA data indicated that the mRNAs encoded by genes located around 3p22 were coexpressed with CMTM6 mRNA in UPS. Both proportion and intensity scores of CMTM6 positively correlated with strong PD-L1 expression (≥ 50%) (both p = 0.023). CMTM6 copy number gain increased CMTM6 expression. Patients with UPS with a high CMTM6 intensity score had a worse prognosis for overall survival. UPS showed variation in CMTM6 copy number and CMTM6 expression. CMTM6 expression was significantly correlated with PD-L1 expression, especially with strong PD-L1 expression.

Study Design: Retrospective diagnostic analysis. Objectives: To establish a new predictor of surgical outcome after surgery for intradural extramedullary spinal tumor (IDEMT) in the thoracic spine, we introduced shape factor (SF), a mathematical description of the morphology of the spinal cord. SF was calculated by dividing object area by the square of perimeter. Materials and Methods: Forty-three consecutive patients with IDEMT, detected by magnetic resonance imaging at the thoracic level with myelopathic signs, were included. Preoperative transverse cross-sectional area (CSA) and perimeter of the spinal cord (perimeter) at the level of maximal compression were measured. SF was calculated as 4π × CSA/(perimeter)2. The association between clinicoradiological factors and surgical outcome of IDEMT was statistically analyzed. Results: Mean CSA, perimeter, and SF were 27.8 ± 15.8 mm2, 28.8 ± 6.1 mm, and 0.385 ± 0.14, respectively. A histogram distribution revealed that perimeter and SF, but not CSA, fit the normal distribution. The patients were subdivided into 2 groups according to postoperative modified Japanese Orthopedic Association Score (mJOA). [group F (favorable): n = 32, mJOA ≥ 9; group UF (unfavorable): n = 11, mJOA < 9). Group UF had significantly lower mean CSA and SF. In univariate analysis of possible predictive factors for IDEMT surgery, greater age, lower preoperative mJOA, and lower SF were significantly associated with unfavorable outcome. In multivariate analysis, lower SF was the only significant predictor of postoperative outcome (odds ratio = 2.66, 95% CI 1.10–6.39, p = 0.0115). Conclusion: Measurements of CSA and perimeter, followed by calculation of SF, may provide valuable quantitative information for the outcome of surgery for IDEMT.

Doxorubicin is a first-line therapy for patients with unresectable advanced soft tissue sarcoma (STS). However, because of cardiotoxicities, it is not used for patients with cardiac problems. Eribulin has exhibited efficacy for advanced STS in second- or later-line treatments. In the present study, we retrospectively analyzed the efficacy and safety of first-line eribulin therapy for patients with advanced STS unable to receive doxorubicin. Six of 28 patients who received eribulin as any line treatment received eribulin as a first-line treatment. The reasons for avoiding doxorubicin were as follows: cardiac problems for four patients and advanced age for two. Median progression-free survival (PFS) of the patients who received eribulin as first-line and, second or later-line therapy were 9.7 months (95% CI: 1.0-not reached) and 3.9 months (95% CI: 2.7–5.9), which were not significantly different. The reasons for discontinuation of eribulin were disease progression and adverse events (2 fatigue and 1 neuropathy) for three patients each. No treatment-related cardiotoxicity was observed. The findings of this study indicated that eribulin exhibits meaningful efficacy for the patients with contraindications for doxorubicin as a first-line treatment without cardiac adverse events. However, appropriate safety management is necessary because older patients are typically among those intolerable of doxorubicin.

Tumor prostheses for the lower limb following resection of musculoskeletal tumors is useful limb salvage management, however, as compared with routine total joint replacement, an increased incidence of deep periprosthetic infection of tumor prosthesis has been observed. The risk factors for periprosthetic infection of tumor prosthesis remain unclear. This study examines the risk factors and outcomes of periprosthetic infection. This was a retrospective observational study including 121 patients (67 males and 54 females) who underwent tumor prosthesis of the lower limb after resection of musculoskeletal tumors between 1 January 2000 and 30 November 2018. Among a total of 121 tumor prostheses, 7 were total femurs, 47 were proximal femurs, 47 were distal femurs, and 20 were proximal tibias. The incidence of postoperative infection and its risk factors were analyzed. Forty-five patients (37%) had osteosarcoma, 36 patients (30%) had bone metastasis, and 10 patients (8%) had soft-tissue tumors invading the bone. The mean operating time was 229 min, and the mean follow-up duration was 5.9 years. Deep periprosthetic infection was noted in 14 patients (12%). In the multivariate analysis, the risk factors for postoperative infection were identified as being male (hazard ratio [HR], 11.2316, p = 0.0100), soft-tissue tumor (HR, 52.2443, p = 0.0003), long operation (HR, 1.0056, p = 0.0184), and radiotherapy (HR, 6.5683, p = 0.0476). The incidence of periprosthetic infection in our institution was similar to that of previous reports. Patients undergoing tumor prosthesis of the lower limb who were male, had a soft-tissue tumor, were predicted to have a long operation, and who underwent radiation, had an increased possibility of postoperative infection.

Introduction To investigate the clinical outcome and prognostic factors of malignant spinal dumbbell tumors (m-SDTs). Methods We retrospectively reviewed the clinical outcome of 22 consecutive cases of m-SDTs and analyzed the prognostic factors associated with worse outcome. Results Nineteen of the 22 cases were managed with surgery (86%), and gross total resection (GTR) was achieved in four cases (21%). The duration of overall survival (OS) ranged from 3 to 140 months, with a median survival time of 15.3 months. The 5 year OS rate was 55.6%. In multivariate analysis, histological subtype (high-grade malignant peripheral nerve sheath tumor) (hazard ratio [HR] 14.9, p = 0.0191), GTR (HR 0.07, p = 0.0343), and presence of local recurrences (HR 11.2, p = 0.0479) were significant and independent predictors of OS. Conclusions On the basis of clinical data, we propose that GTR and prevention of local recurrence may improve the clinical outcome of m-SDTs.

Osteosarcoma is an aggressive mesenchymal malignancy of the bone. Patient-derived models are essential tools for elucidating the molecular mechanisms associated with poor prognosis and the development of novel anticancer drugs. This study described the establishment of a patient-derived cancer model of osteosarcoma. Primary osteosarcoma tumor tissues were obtained from an osteosarcoma patient and inoculated in the skin of immunodeficient mice, followed by transplantation to other mice upon growth. Cells were maintained in monolayer cultures, and the capability of spheroid formation was assessed by seeding the cells on culture dishes. The invasion ability of cells was monitored by Matrigel assay, and genomic and proteomic backgrounds were examined by mass spectrometry. A cell line was established from patient-derived tumors and showed similar histology to that of the primary tumor tissue. Additionally, these cells formed spheroids on low-attachment tissue-culture dishes and exhibited invasive capabilities, and we confirmed that the genomic backgrounds were similar between patient-derived xenograft tumors and the cell line. Furthermore, the proteome of the patient-derived tumors and the cells exhibited similar, but not identical, patterns to that of the original tumor tissue. Our results indicated that this patient-derived xenograft model and cell line would be useful resources for osteosarcoma research.

Synovial sarcoma (SS) is a malignant soft tissue neoplasm harboring SS18-SSX fusion gene and is histologically characterized by spindle cells and epithelial components. Some investigations have demonstrated that desmoplastic reaction (DR) is an independent prognostic factor of cancers. However, it remains unknown whether DR is of predictive value for the prognosis of synovial sarcoma patients. Here, we reviewed the clinical and histological findings of 88 patients with SS. We defined DR as hyalinized collagenous structures and classified the degree of DR as follows: none, mild, moderate, and severe. Overall, 23 SS cases (24%) showed moderate or severe DR histologically. Statistically, the cases with moderate or severe degree of DR showed poorer prognosis than those with no or mild DR (local recurrence: P = 0.0059, distant metastasis: P = 0.0002, tumor death: P = 0.0382). The findings of the study suggest that the DR of synovial sarcoma could be an important prognostic factor.

Pazopanib, trabectedin, and eribulin are administered for the treatment of soft tissue sarcomas (STSs), however, there is little consensus on which agent should be preferentially used in a clinical setting. This study assessed whether peripheral immune-related markers served as a useful reference when selecting pazopanib, trabectedin, or eribulin. This study included 63 patients who were administered pazopanib, trabectedin, or eribulin for advanced STSs between March 2015 and December 2020. Patients were divided into three groups based on the first drug administered among these three drugs. Differences in overall survival (OS) or progression-free survival (PFS) among the three groups were analyzed. OS showed no significant differences among the drugs administered first. For patients with low neutrophil-to-lymphocyte ratio (NLR), the OS of patients administered pazopanib as the first choice was shorter than the others (hazard ratio [HR] = 9.53, 95% confidence interval [CI] = 1.94–18.13, p = 0.0018). In the low platelet-to-lymphocyte ratio (PLR) subgroup, the OS of the patients administered eribulin for the first choice was longer than that of the others (HR = 0.32, 95%CI = 0.10–0.98, p = 0.046). Therefore, NLR and PLR might be used as prognostic indicators to dictate whether STS patients receive pazopanib, trabectedin, or eribulin.

Purpose While radiotherapy is generally an acceptable treatment for metastatic spinal cord compression, surgical intervention is controversial due to the invasiveness and diversity of diseases in the patients being considered. The ideal treatment, therefore, depends on the situation, and the most acute treatment possible is necessary in patients presenting with myelopathy. We compared the neurological outcomes between radiotherapy and surgery in patients with metastatic spinal cord compression presenting with myelopathy. Methods A total 54 patients with metastatic spinal cord compression presenting with myelopathy treated in our institution between 2006 and 2016 were analyzed retrospectively. Twenty patients were selected by radiotherapy alone (radiation group), and 36 patients were selected by decompression and stabilization surgery with or without radiotherapy (surgery group). The neurological outcomes and complications were compared between the two treatment groups. Results Seven patients initially in the radiation group underwent surgery because of a substantial decline in their motor strength during radiotherapy. One of the remaining 13 patients (8%) in the radiation group and 30 of the 34 patients (88%) in the surgery group showed improvement in their neurological symptoms (P

Despite advances in our understanding of the underlying molecular drivers of sarcomas, few treatments are available with proven benefit for advanced metastatic sarcomas. Immunotherapy has value in this setting for some types of cancers, but sarcomas, with their multiplicity of rare types, have not been characterized in detail for their expression of targetable immune biomarkers. This study provides the most systematic evaluation to date of tumor-infiltrating lymphocytes and immune checkpoint biomarker expression in sarcomas. We examined by morphology and immunohistochemistry 1072 sarcoma specimens representing 22 types, in addition to 236 benign bone and soft-tissue tumors. Genomically-complex sarcoma types-those driven by mutations and/or copy-number alterations-had much higher numbers of tumor-infiltrating lymphocytes than translocation-associated sarcomas. Prior exposure to radiotherapy was associated with increased immune infiltrates. Higher lymphocytic infiltration was associated with better overall survival among the non-translocation-associated sarcomas. Expression of PD-1 and CD56 were associated with worse overall survival. LAG-3 and TIM-3, two emerging immune checkpoints, were frequently expressed in most sarcoma types. Indeed, most cases positive for PD-(L)1 coexpressed one or both of these novel biomarkers, providing a potential rationale in support for trials targeting LAG-3 and/or TIM-3 in conjunction with PD-1 inhibition.

Myxoid liposarcomas (MLSs) are genetically defined by the presence of DDIT3 gene fusions and most commonly arise in the extremities of young adults. Whether MLSs develop primarily in the retroperitoneum is controversial, and a recent retrospective study found no molecularly confirmed examples. Because MLSs tend to metastasize to deep soft tissues, purported examples of primary retroperitoneal lesions might represent distant metastasis, most commonly from extremities. In addition, well-differentiated or dedifferentiated liposarcomas, which are characterized by MDM2 amplifications, may exhibit prominent myxoid changes and mimic MLSs. Here, we document 5 cases of MLSs that originated in the retroperitoneum that were identified through critical clinicopathologic reevaluation. These cases accounted for 2.3% of 214 primary retroperitoneal liposarcomas and 3.2% of 156 MLSs in our database. They occurred in 3 men and 2 women with a median age of 32 years. All tumors were localized to the retroperitoneum at presentation, and no patient developed extra-abdominal recurrences during the clinical course (median, 50 mo). All 5 cases exhibited at least focal classic histologic findings. All harbored DDIT3 gene rearrangements, and none harbored MDM2 amplifications according to fluorescence in situ hybridization. This study demonstrates that primary MLSs can occur in the retroperitoneum, albeit rarely, and can be accurately diagnosed through combined clinicopathologic and molecular analysis.

Leiomyosarcoma (LMS) of soft tissue is a sarcoma with smooth-muscle differentiation, and conventional chemotherapy does not improve its outcome. The application of novel antitumor agents and precise prognostication has been demanded. The expression of the protein Forkhead box M1 (FOXM1), a member of the FOX family, is considered an independent predictor of poor survival in many cancers and sarcomas. However, the expression status of FOXM1 in LMS is poorly understood. The purposes of this study were to examine the correlation between the expression of FOXM1 and clinicopathologic or prognostic factors and to clarify the efficacy of FOXM1 target therapy in LMS. We evaluated the immunohistochemical expressions of FOXM1 using 123 LMS tumor specimens. Univariate and multivariate survival analyses revealed that FOXM1 expression was associated with poor prognosis in LMS. An in vitro study was then carried out to examine the antitumor effect of a FOXM1 inhibitor (thiostrepton) and siRNA on a novel LMS cell line, TC616. We also assessed the efficacy of the combined use of doxorubicin and thiostrepton. Thiostrepton showed dose-dependent antitumor activity and TC616 cells treated with the combination of thiostrepton and doxorubicin showed lower proliferation compared to those treated with either drug individually. FOXM1 interruption by siRNA decreased cell proliferation and increased chemosensitivity. In conclusion, FOXM1 has potential to be a therapeutic target for LMS.

Eribulin is a new drug to treat soft tissue sarcoma (STS) that exerts antitumor activity by binding to microtubules. The prognosis of STS is poor, and eribulin is expected to improve the treatment outcome. We observed several cases that exhibited resistance to eribulin and developed an eribulin-resistant leiomyosarcoma cell line to investigate the mechanism of resistance. The IC50 of eribulin was 125 times higher in the resistant cell line than in the parental cell line, and eribulin did not induce G2/M arrest in resistant cells. The resistant cell line showed increased expression of MDR1 transcript, but protein levels and functional analysis results were similar to the parental cell line. We found that class III β-tubulin (TUBB3) was overexpressed in the resistant cell line, and siRNA knockdown of TUBB3 partially recovered sensitivity to eribulin. TUBB3 expression in clinical samples varied, suggesting that TUBB3 has the potential to be a biomarker for selection of anticancer drugs and may be a target for overcoming resistance to eribulin.

Myositis ossificans (MO) is a rare benign cause of heterotopic bone formation in soft tissue that most commonly affects young adults, typically following trauma. We report the case of an 11-year-old girl who developed MO mimicking osteosarcoma in her right shoulder. Plain radiography and computed tomography showed poorly defined flocculated densities in the soft tissue and a periosteal reaction along the proximal humerus. On magnetic resonance imaging, the mass displayed an ill-defined margin and inhomogeneous signal change. Histologically, the mass had a pseudosarcomatous appearance. Based on these findings, the patient was initially misdiagnosed with osteosarcoma at another hospital. The diagnosis was difficult because the patient was 11 years old and had no trauma history, with atypical radiographic changes and a predilection for the site of origin for osteosarcomas. We finally made the correct diagnosis of MO by carefully reviewing and reflecting on the pathological differences between stages.

Phosphaturic mesenchymal tumour, mixed connective tissue variant (PMT-MCT), is a tumour of uncertain differentiation, characterised by 'smudgy/grungy' calcification and vitamin D-resistant phosphaturic osteomalacia. Fibroblast growth factor (FGF)23 is recognised as a reliable marker of PMT-MCT, but quantitative evaluation has never been performed. We reviewed cases of tumour-associated osteomalacia or histologically definitive PMT-MCT without osteomalacia using histological, immunohistochemical and genetic methods and evaluated the diagnostic significance of these findings.A total of 19 tumours from 14 cases diagnosed previously as PMT-MCT were retrieved, on which immunohistochemical staining, reverse transcription-polymerase chain reaction (RT-PCR) and fluorescence in-situ hybridisation (FISH) analysis were performed. Histologically, fibrous capsule, calcification and giant cell reaction tended to be observed in soft-tissue PMT-MCT, while PMT-MCT of bone and multiple PMT-MCT showed an infiltrative growth pattern. The immunohistochemical results were as follows: the tumour cells were positive for FGF23 (nine of 12, 75%), FGFR1 (11 of 11, 100%), CD56 (12 of 14, 85.7%) and E26 oncogene homologue (ERG) (5 of 13, 38.4%). The sole malignant tumour was positive for p53. FGF23 mRNA was detected in seven of 14 formalin-fixed paraffin-embedded (FFPE) specimens and all five frozen specimens by RT-PCR. The level of FGF23 mRNA, which was determined by real-time PCR, varied among the phosphaturic cases. Two of 17 tumours were positive for FGFR1 gene rearrangement.It was considered that PMT-MCT is a histopathological entity with or without phosphaturia, with varying levels of FGF23 mRNA, and with or without fibronectin 1 (FN1)-FGFR1 fusion gene. The authors propose that the histology of PMT-MCT differs depending on its location, such as bone or soft tissue, which could complicate the differential diagnosis.

A 35-year-old Japanese man presented with a 1-month history of limited flexion and radiating pain in the left middle and ring fingers. A physical examination revealed a hard nodular mass in his left palm. Magnetic resonance imaging showed a 2 × 1.5 × 1 cm mass of low intensity on T1-weighted images and high intensity on T2-weighted images and gadolinium enhancement. The tumor was marginally resected, adhering to the flexor digitorum profundus of both the third and fourth fingers. The histological diagnosis was fibroma of tendon sheath. After the surgery, the range of motion and hand function were improved. No recurrence has been observed. Fibroma of tendon sheath usually arises on the fingers and hands with strong attachment to the tendon or tendon sheath. The tumor in the present case probably limited the range of flexion of the fingers by obstruction of the transverse carpal ligament.

Dermatofibrosarcoma protuberans (DFSP) is a cutaneous mesenchymal tumor of intermediate malignancy and fibroblastic/myofibroblastic differentiation. Fibrosarcomatous (FS) component is a high-grade component of DFSP. The detailed oncogenic difference between DFSP and FS components is not clear. We thus investigated the Akt-mTOR pathway in both components. We used 65 tumor samples obtained from 65 patients. The phosphorylation of Akt-mTOR pathway proteins (Akt, mTOR, 4EBP1, and S6RP) and PDGFRα/β was assessed by immunohistochemical staining, the results of which were confirmed by Western blotting. The immunohistochemical results were as follows: in ordinary DFSP components, p-PDGFRα-positive tumors were 41.9% (18/43 cases), p-PDGFRβ 55.8% (24/43 cases), p-Akt 51.2% (22/43 cases), p-mTOR 39.5% (17/43 cases), p-4EBP1 46.5% (20/43 cases), and p-S6RP 41.8% (18/43 cases); in DFSP components of FS-DFSP, 52.6% (10/19 cases), 47.4% (9/19 cases), 52.6% (10/19 cases), 36.8% (7/19 cases), 52.6% (10/19 cases), and 52.6% (10/19 cases); and in FS components, 45.5% (10/22 cases), 36.4% (8/22 cases), 72.7% (16/22 cases), 54.5% (12/22 cases), 72.7% (16/22 cases), and 68.2% (15/22 cases), respectively. There were significant positive correlations of the phosphorylation of most of the Akt-mTOR pathway proteins (p-Akt, p-mTOR, p-4EBP1, and p-S6RP) with each other (P < .05). Phospho-PDGFRβ was well correlated with the phosphorylation of Akt-mTOR pathway proteins in DFSP components of ordinary and FS-DFSPs, but these correlations were weaker in FS components. This study suggested the association of activation of Akt-mTOR pathway proteins and PDGFR with the progression of DFSP to FS. The Akt-mTOR pathway is thus a potential therapeutic target in imatinib-resistant DFSP/FS.

Background Malignant peripheral nerve sheath tumor (MPNST) is a rare soft tissue sarcoma with poor prognosis. Hypoxia-inducible factor 1 (HIF-1) plays a crucial role in the cellular response to hypoxia and regulates the expression of multiple genes involved in tumor progression in various cancers. However, the importance of the expression of HIF-1α in MPNSTs is unclear. Methods The expression of HIF-1α was examined immunohistochemically in 82 MPNST specimens. Cell culture assays of human MPNST cells under normoxic and hypoxic conditions were used to evaluate the impact of anti-HIF-1α–specific siRNA inhibition on cell survival. A screening kit was employed to identify small molecules that inhibited HIF-1α. Results The nuclear expression of HIF-1α was positive in 75.6% of MPNST samples (62/82 cases). Positivity for HIF-1α was a significant poor prognostic factor both in univariate (P = 0.048) and multivariate (P ≤ 0.0001) analyses. HIF-1α knockdown abrogated MPNST cell growth, inducing apoptosis. Finally, chetomin, an inhibitor of HIF-1α, effectively inhibited the growth of MPNST cells and induced their apoptosis. Conclusion Inhibition of HIF-1α signaling is a potential treatment option for MPNSTs.

Background and Purpose. Carbon-ion radiotherapy (C-ion RT) was effective therapy for inoperable spinal and paraspinal sarcomas. However, a significant adverse event following radiotherapies is vertebral compression fractures (VCFs). In this study, we investigated the incidence of and risk factors for post-C-ion RT VCFs in patients with spinal or paraspinal sarcomas. Material and Methods. Thirty consecutive patients with spinal or paraspinal sarcomas treated with C-ion RT were retrospectively reviewed. Various clinical parameters and the Spinal Instability Neoplastic Score (SINS) were used to evaluate the risk factors for post-C-ion RT VCFs. Results. The overall incidence of VCFs was 23% (median time: 7 months). Patients with VCFs showed a markedly higher SINS score (median value, 9 points) than those without VCF (5 points). The area under the receiver operating characteristic curve for the SINS score was 0.88, and the optimum SINS cut-off score was 8 points. The cumulative incidence of VCFs at 1 year was 9% for patients with a SINS score under 8 points, versus 80% for those with a SINS score of 8 points or higher (p<0.0001). Conclusions. In patients with a SINS score of 8 points or higher, referral to a spine surgeon for stabilization and multidisciplinary discussion is appropriate.

Background and Purpose. Primary malignant spine/spinal tumors (PMSTs) are rare and life-threatening diseases. In this study, we demonstrated the advantage of volume-based 18F-FDG PET/CT metabolic parameter, metabolic tumor volume (MTV), for assessing the aggressiveness of PMSTs. Materials and Methods. We retrospectively reviewed 27 patients with PMSTs and calculated SUVmax, MTV, and total lesion glycolysis (TLG) to compare their accuracy in predicting progression-free survival (PFS) and overall survival (OS) by receiver operating characteristic (ROC) curve analysis. Univariate and multivariate analyses were used to compare the reliability of the metabolic parameters and various clinical factors. Results. MTV exhibited greater accuracy than SUVmax or TLG. The cut-off values for PFS and OS derived from the AUC data were MTV 45 ml and 83 ml and TLG 250 SUV⁎ml and 257 SUV⁎ml, respectively. MTV above cut-off value, but not TLG, was identified as significant prognostic factor for PFS by log-lank test (p=0.04). In addition, MTV was the only significant predictive factors for PFS and OS in the multivariate analysis. Conclusions. MTV was a more accurate predictor of PFS and OS in PMSTs compared to TLG or SUVmax and helped decision-making for guiding rational treatment options.

BACKGROUND Solitary fibrous tumors (SFTs) are soft tissue tumors of intermediate malignancy that rarely metastasize. Although unresectable SFTs are reported to have a poor prognosis, to the authors' knowledge there is currently no effective therapy. Molecular target therapy is a promising approach for patients with unresectable tumors, but knowledge of the molecular biology of SFTs is currently insufficient to support such therapy. The current study investigated the activation of receptor tyrosine kinases (RTKs) and the Akt-mammalian target of rapamycin (Akt-mTOR) pathway in SFTs as therapeutic targets. METHODS The phosphorylation statuses of Akt-mTOR pathway proteins (p-Akt, p-mTOR, phosphorylated 4E-binding protein [p-4EBP1], and phosphorylated S6 ribosomal protein [p-S6RP]) and RTKs (phosphorylated platelet-derived growth factor receptor-α [p-PDGFRα], p-PDGFRβ, p-c-met, and phosphorylated insulin-like growth factor-1 receptor-β [p-IGF-1Rβ]) were assessed by immunohistochemistry in 66 samples of SFTs, and the data were compared with clinicopathological and histopathological findings. The expression of phosphorylated proteins was assessed by Western blot analysis in 6 frozen samples. RESULTS The immunohistochemical results were as follows: p-Akt, 56.0% (nuclear and cytoplasmic staining); p-mTOR, 69.6% (nuclear and cytoplasmic staining); p-4EBP1, 80.3% (nuclear and cytoplasmic staining); p-S6RP, 69.6% (cytoplasmic staining); p-PDGFRα, 39.0% (cytoplasmic staining); p-PDGFRβ, 52.0% (cytoplasmic staining); p-c-met, 37.8% (nuclear staining) and 19.6% (cytoplasmic staining); and p-IGF-1Rβ, 16.6% (nuclear staining). Phosphorylation of the Akt-mTOR pathway proteins was correlated with one another except for p-Akt with S6RP. p-PDGFRβ and p-IGF-1Rβ were correlated with p-Akt. Moreover, significant relationships were noted between disease-free survival or overall survival and the presence of hypoglycemia, necrosis, cystic and myxoid degeneration, and atypical findings. CONCLUSIONS The Akt/mTOR pathway was activated in approximately 50% of the cases of SFTs and was associated with RTKs, which were phosphorylated at different rates. Thus, the Akt-mTOR pathway may be involved in the tumorigenesis of SFTs. Cancer 2014;120:864–876. © 2013 American Cancer Society.

Malignant peripheral nerve sheath tumor is a malignant tumor showing nerve sheath differentiation. Approximately one-half of malignant peripheral nerve sheath tumors arise from a benign peripheral nerve sheath tumor, which is commonly a neurofibroma in patients with neurofibromatosis type 1. Malignant peripheral nerve sheath tumor arising in a sporadic schwannoma of soft tissue is extremely rare. In this condition, malignant cells usually show epithelioid morphology, meeting the diagnostic criteria for epithelioid malignant peripheral nerve sheath tumor. Here, we present an extraordinary case of spindle cell-type malignant peripheral nerve sheath tumor arising in a schwannoma on the back of a 58-year-old woman without neurofibromatosis. The malignant component showed hypercellular spindle cell proliferation with high mitotic activities; in contrast, the benign component showed hypocellular spindle cell proliferation in a palisading pattern and with Verocay bodies. Immunohistochemical S-100 protein staining showed a clear contrast between the malignant (negative) and benign (positive) components, which was useful for differentiating cellular schwannoma. Recognizing this rare condition is helpful in the pathologic diagnosis of schwannoma showing cellular proliferation in part.

BACKGROUND The Akt/mammalian target of rapamycin (mTOR) pathway, downstream from phosphatidylinositol 3-kinase (PI3K), mediates cell survival and proliferation. Although this pathway reportedly contributes to the progression of synovial sarcoma, its prognostic impact has not been clarified. METHODS The authors analyzed clinicopathologic data and phosphorylation status of Akt (a serine/threonine kinase also known as protein kinase B), mTOR, the eukaryotic translation initiation factor 4E binding protein (4E-BP1), and the S6 ribosomal protein by immunohistochemical analysis of 120 formalin-fixed, paraffin-embedded samples and by Western blot analysis of 24 frozen samples from 112 patients with synovial sarcoma. RESULTS Akt, mTOR, 4E-BP1, and S6 were activated in 76.5%, 67.6%, 59.6%, and 42.6% of samples, respectively. Immunohistochemically positive phosphorylated (p) mTOR (pmTOR) and p4E-BP1 results were correlated with higher mitotic activity, and positive p4E-BP1 results were correlated with greater necrosis. No mutations around the hot spots in the PI3K catalytic subunit α (PI3KCA) and Akt1 genes were observed. In multivariate analysis of clinicopathologic parameters, frequent mitosis was a risk factor for shorter overall survival; and male sex, visceral location, larger tumor size, and frequent mitosis were identified as risk factors for shorter event-free survival. Positive pmTOR and p4E-BP1 results were correlated significantly with shorter overall survival, and positive p4E-BP1 results were correlated with shorter event-free survival in univariate analysis. Positive pAkt results were associated significantly with shorter event-free survival in multivariate analysis. CONCLUSIONS In this study, the Akt/mTOR pathway was activated and was associated with worse clinical and pathologic behavior in patients with synovial sarcoma. The authors propose that this pathway may have potential as a therapeutic target. Cancer 2013;119:3504–3513.. © 2013 American Cancer Society.

Aims We aimed to elucidate the clinicopathological and immunohistochemical features of leiomyosarcoma (LMS) of the gastrointestinal (GI) tract. Methods and results We encountered seven cases of GI-LMS in the colon (n = 4), rectum (n = 1), jejunum (n = 1) and stomach (n = 1). They ranged from 1 to 25 cm (median, 8.5 cm) in size and had high mitotic counts (median 38 per 50 high-power fields). Morphologically, the tumours were composed mainly of spindle cells with eosinophilic cytoplasm and various degrees of nuclear atypia and pleomorphism. Immunohistochemically, the tumours were positive for α-smooth muscle actin (86%), muscle-specific actin (71%), desmin (86%), calponin (71%), h-caldesmon (57%) and smoothelin (71%). All were negative for KIT, CD34, protein kinase C theta and DOG1. Local recurrence and distant metastasis occurred in one and three patients, respectively. We then reviewed 55 cases of GI-LMS from the era following the recognition of gastrointestinal stromal tumours. Among 29 of 55 cases for whom follow-up information was available, the estimated 5-year overall survival rate was 51.6%; tumour size ≥5 cm was correlated significantly with shorter overall survival time (P = 0.0016), while mitotic count (≥50 or ≥100 per 50 high-power fields) proved to be no prognostic factor. Conclusions GI-LMSs have distinctive clinicopathological and immunohistochemical features and exhibit aggressive biological behaviour.

Bone infarct-associated sarcoma is a rare sarcoma, accounting for less than 1% of all bone sarcomas. Its histology usually reflects a high-grade sarcoma, such as malignant fibrous histiocytoma of bone or conventional osteosarcoma. Low-grade sarcoma arising from bone infarct has not been described well in the literature. Here, we present a 17-year follow-up of a female patient with bone infarct in her right humerus, from which a low-grade central osteosarcoma developed during follow-up. A histologic diagnosis of low-grade central osteosarcoma was confirmed by immunohistochemical expression of MDM2 and CDK4. She underwent a wide resection surgery. As of 4 years after surgery, she has remained free of any evidence of recurrence or metastasis. Here, we present clinical and pathologic findings of our case in detail and discuss the differential diagnoses of this extremely rare condition.

Fibrocartilaginous mesenchymoma (FCM) of the bone is a rare tumor, with only 21 reported cases since 1984. It usually occurs in the long bones of children and adolescents, but in this case, the tumor arose in the pubic bone. The pathological diagnosis of FCM can be challenging, and the treatment should be a wide resection because of its locally aggressive behavior. Histologically, our tumor was composed of a lobular proliferation of spindle cells juxtaposed to the cartilaginous tissue, lacking cytological atypia. Enchondral ossification was observed at the periphery of the cartilaginous nodules, and hypertrophic chondrocytes was recognized, reminiscent of an epiphyseal plate. Intralesional resection followed by phenol and ethanol cauterization was performed in place of the usual wide resection. We report a case of FCM arising in a rare anatomical site, the pubic bone, successfully treated by intralesional resection. One year after the surgery, the patient is free of disease.

We recognized immunoreactivity for the α subset of inhibin and synaptophysin in synovial sarcomas with granular cell features. Histologic findings of 90 cases of synovial sarcoma were reviewed. Two (2.2%) of the 90 cases had granular cell features, showing sheet or nested proliferation of characteristic epithelioid cells with abundant eosinophilic and granular cytoplasm, in addition to the typical spindle cell component. The 2 cases were both female (aged 86 and 76 years). The tumors were located in the foot and the retroperitoneum and measured 3.5 and 14 cm in maximum diameter. Reverse transcriptase polymerase chain reaction analysis revealed SS18-SSX1 transcripts in both cases. SS18 gene rearrangement was detected in granular cells as well as spindle cells by chromogenic in situ hybridization. Immunohistochemistry found the granular cells to be positive for inhibin-α in both cases and for synaptophysin in 1 case, whereas spindle cells were not. Thirty-six cases (20 monophasic fibrous, 11 biphasic, and 5 poorly differentiated synovial sarcomas) were additionally examined for comparison; they showed no immunoreactivity for inhibin-α or synaptophysin. This is the first report of immunoreactivity for inhibin-α and synaptophysin in synovial sarcoma. These immunohistochemical findings might be characteristic of synovial sarcomas with granular cell features.

Purpose: p14ARF, p15INK4b, and p16INK4a are tumor suppressor genes that are located closely at 9p21 and are often coinactivated by genetic or epigenetic alterations. Malignant peripheral nerve sheath tumor (MPNST) is a rare sarcoma with poor prognosis. However, the prognostic implications of inactivation of p14ARF, p15INK4b, and p16INK4a in MPNSTs have not been adequately investigated. Here we carried out a genetic, epigenetic, and expression analysis of p14ARF, p15INK4b, and p16INK4a, and clarified the prognostic significance of their inactivation in MPNSTs. Experimental Design: p14ARF, p15INK4b, and p16INK4a protein expressions were assessed by immunohistochemistry in 129 formalin-fixed samples of MPNST including 85 primary tumors. Thirty-nine samples, for which frozen material was available, were also investigated by Western blotting and quantitative reverse transcription PCR (RT-PCR) to detect p14ARF, p15INK4b, and p16INK4a protein and mRNA expression, and by multiplex real-time PCR, PCR single strand conformation polymorphism and methylation-specific PCR to detect p14ARF, p15INK4b, and p16INK4a gene alterations. Results: Immunohistochemically decreased expressions of p14ARF, p15INK4b, and p16INK4a were observed in 48%, 54%, and 49% of primary MPNSTs, respectively, and were significantly correlated with their concordant mRNA levels. As for gene alterations, homozygous deletion of CDKN2A was detected in one third of the cases. Inactivation of p14ARF and p16INK4a was associated with poor prognosis by both univariate and multivariate analyses. Furthermore, cases with inactivation of all p14ARF, p15INK4b, and p16INK4a genes showed the worst prognosis in a combined prognostic assessment. Conclusion: A comprehensive analysis of p14ARF, p15INK4b, and p16INK4a inactivation status provides useful prognostic information in MPNSTs. Clin Cancer Res; 17(11); 3771–82. ©2011 AACR.

Dedifferentiated liposarcoma is defi ned as a malignant adipocytic neoplasm showing a transition from welldifferentiated liposarcoma to nonlipogenic sarcoma. In most cases the nonlipogenic component presents with high-grade morphology, although the concept of lowgrade dedifferentiation has increasingly been recognized in recent years. Radiologically, especially with magnetic resonance imaging (MRI), a typical presentation of dedifferentiated liposarcoma is the coexistence of fatty and nonfatty components, so a radiological diagnosis of ordinary (high-grade) dedifferentiated liposarcoma is not diffi cult in most cases. On the other hand, the radiological fi ndings of low-grade dedifferentiated cases have not been investigated at all. Dedifferentiated component of (high-grade) dedifferentiated liposarcoma usually presents low intensity on T1weighted images and heterogeneous high intensity on T2-weighted images. However, we experienced a case where the dedifferentiated component showed low to intermediate intensity on both T1and T2-weighted MR images. In this report, we present a case of lowgrade dedifferentiated liposarcoma of the neck with emphasis on the correlation between MRI and pathological fi ndings. We also discuss the importance of recognizing the radiological fi ndings of such a case.

腰椎後方椎体間固定術（PLIF）の合併症としての脊椎炎の早期診断に MRI が有用であるか検討した．当科で PLIF を施行した18例（21椎間）について，術後2週から3週で MRI 矢状断像を撮影して評価を行った．非感染例においても高率に椎体の信号変化・終板の不整像を示し，PLIF 後の脊椎炎の診断においては術後早期の MRI は信頼性が低く，臨床経過から総合的に判断する必要があると思われた．

A 10-year-old boy diagnosed with unresectable giant cell tumor of bone in the sacrum was treated with a bone modifying agent denosumab. Administration of denosumab showed excellent clinical response without any major complications, and the tumor was surgically removed afterwards. However, 4 months after discontinuing denosumab, the patient developed severe hypercalcemia (15.2 mg/dl). There was a sharp surge in the levels of bone resorption markers, indicating that disregulated overt bone resorption after the discontinuation of denosumab led to hypercalcemia. The patient was treated with bisphosphonate and barely recovered from the life-threatening conditions. This case shows that a robust rebound of bone resorption may occur following cessation of denosumab and suggests that hypercalcemia is an underappreciated side effect of denosumab therapy in children.

Alveolar soft part sarcoma (ASPS) is a rare soft tissue tumor characterized by pseudoalveolar growths associated with abundant sinusoidal vessels. It has a high proclivity to blood-borne metastasis, but the exact mechanism of spread has not been widely discussed, and detailed histological analysis of vascular involvement is still lacking. In this study, we histologically analyzed 32 surgically resected ASPSs, with particular attention to the mode of vascular involvement. Among 188 instances of unequivocal vascular involvement, 184 (98%) were in the form of variously sized cohesive clusters that were completely enveloped by endothelial cells, confirmed by CD31 immunostaining. Discohesive intravascular tumor cells without endothelial wrapping were rare (2%). The clinical relevance of vascular involvement was supported by survival analysis where the average number of vascular involvements per slide was an independent risk factor for shorter progression-free survival. Our findings suggest that ASPSs do not actively break through the vascular walls to initiate the metastatic process. They instead suggest that ASPSs almost exclusively follow the recently postulated "invasion-independent mechanism" for entry into circulation, in which cancer cells are shed into vessels, while being completely enveloped by endothelial cells, and are subsequently entrapped at recipient organs. Because the latter mechanism is reportedly dependent on tumor angiogenesis and vascular remodeling, our data provide a morphological rationale for the use of anti-angiogenic therapy to treat ASPSs.

e22544Background: Sarcoma clinical guidelines often emphasize the evaluation of patients by an expert multidisciplinary team, and thus in many countries, care is centralized to treatment centers. However, there are no standard guidelines for referrals of sarcoma patients in Japan, and the overall picture of where and by whom they are treated has never been systematically investigated. Methods: We used hospital-based cancer registry and health claims data of sarcoma patients diagnosed in Japan in 2012 and 2013. We analyzed the distribution of patients across hospitals and the extent of centralization of care across treatment modality and cancer topography. Results: We identified 1032 bone and 7257 soft-tissue sarcoma (STS) patients who were newly diagnosed in 2012 and 2013. Bone sarcomas occurred in the limbs in 55% of the patients, with 73% treated by orthopedic surgeons. Care was weakly centralized to 9 high-volume hospitals ( > 10 new cases per year) and 120 hospitals with 1-9 new cases. Care was greatl...

Purpose: Malignant peripheral nerve sheath tumor (MPNST) is a rare soft tissue sarcoma with poor prognosis. MPNSTs occur frequently in patients with neurofibromatosis type 1 (NF1), in which NF1 gene deficiency leads to Ras hyperactivation. Ras activation causes the subsequent activation of the AKT/mTOR and Raf/MEK/ERK pathways and regulates cellular functions. However, the activation profiles of the AKT/mTOR and MAPK pathways in MPNSTs are poorly understood. The purposes of this study are to examine the correlation between the activation of these pathways and clinicopathologic or prognostic factors and to identify candidate target molecules in MPNST. Moreover, we assessed the antitumor effects of the inhibitor of candidate target. Experimental Design: Immunohistochemistry was conducted to evaluate the activation profiles of AKT/mTOR and MAPK pathways using 135 tumor specimens. Immunohistochemical expressions were confirmed by Western blotting. Then, an in vitro study was conducted to examine the antitumor effect of the mTOR inhibitor on MPNST cell lines. Results: Phosphorylated-AKT (p-AKT), p-mTOR, p-S6RP, p-p70S6K, p-4E-BP1, p-MEK1/2, and p-ERK1/2 expressions were positive in 58.2%, 47.3%, 53.8%, 57.1%, 62.6%, 93.4%, and 81.3% of primary MPNSTs, respectively. Positivity for each factor showed no difference between NF1-related and sporadic MPNSTs. Univariate prognostic analysis revealed that p-AKT, p-mTOR, and p-S6RP expressions were associated with poor prognosis. Furthermore, activation of each p-mTOR and p-S6RP was an independent poor prognostic factor by multivariate analysis. mTOR inhibition by Everolimus showed antitumor activity on MPNST cell lines in vitro. Conclusion: mTOR inhibition is a potential treatment option for both NF1-related and sporadic MPNSTs. Clin Cancer Res; 19(2); 450–61. ©2012 AACR.

Signal transducer and activator of transcription (STAT) 3 mediates a broad range of biological processes, including cell survival and proliferation, and STAT3 has generally been regarded as a pro-oncogenic transcription factor. We investigated the phosphorylation status of STAT3 and the protein expression of the suppressor of cytokine signaling 3 (SOCS3) by immunohistochemistry in 145 formalin-fixed, paraffin-embedded samples of soft tissue leiomyosarcoma (LMS), including 129 primary tumors. Eight benign soft tissue smooth muscle tumors were also examined. Thirteen frozen LMS samples, which were paired with normal tissue samples, were assessed by Western blot analysis for the phosphorylation of STAT3 and SOCS3 expression. Immunohistochemical study showed that the phosphorylation of STAT3 was not a major event in LMS (37%). Moreover, phosphorylated STAT3 (pSTAT3) expression was significantly correlated with a better prognosis. Overexpression of SOCS3 was recognized in 52% of the cases and negatively correlated with pSTAT3 expression. Among the benign tumors, 63 and 25% were positive for pSTAT3 and SOCS3, respectively. Immunoblotting detected pSTAT3 in all tumor samples, but at lower levels than in non-neoplastic tissue. SOCS3 was detected in 92% (12 out of 13) of tumor tissues, but in none of the normal tissues. Contrary to the previous investigations of many other malignant tumors, STAT3 was inactivated in most LMS cases, likely owing to SOCS3 overexpression. STAT3 might not contribute to the progression of soft tissue LMS, and the phosphorylation status of STAT3 has the potential to be a favorable prognostic marker of LMS.

BACKGROUND: The Akt/mammalian target of rapamycin (mTOR) pathway mediates cell survival and proliferation and contributes to tumor progression. Soft tissue leiomyosarcoma continues to show poor prognosis, and little is known about its mechanisms of tumor progression. Here the authors investigated the significance of activation of the Akt/mTOR pathway in soft tissue leiomyosarcomas. METHODS: The phosphorylation status of Akt, mTOR, S6, and the eukaryotic translation initiation factor 4E-binding protein (4E-BP1) and the protein expression of phosphatase and tensin homologue (PTEN) were assessed by immunohistochemistry in 145 formalin-fixed paraffin-embedded samples of soft tissue leiomyosarcoma including 129 primary tumors. The expression of phosphorylated Akt and mTOR in comparison with their total forms was assessed by Western blot analysis in 13 frozen samples, which were paired with normal tissue samples. Moreover, 39 frozen tumor samples were analyzed for PIK3CA and AKT1 gene mutation. RESULTS: Immunohistochemically, phosphorylated forms of Akt, mTOR, S6, and 4E-BP1 were positive in 78.3%, 72.6%, 74.5%, and 70.5% of the samples, respectively. These results were correlated with each other, and associated with higher mitotic activity and adverse prognosis. Decreased expression of PTEN was recognized in only 19.7% and had no statistically significant correlation with Akt or other molecules. Immunoblotting showed a high degree of Akt and mTOR phosphorylation in tumor samples compared with that in non-neoplastic tissue. Mutational analysis failed to reveal any PIK3CA or AKT1 mutations around the hot spots. CONCLUSIONS: The Akt/mTOR pathway was activated in most cases of soft tissue leiomyosarcoma and associated with worse clinical behavior and aggressive pathological findings. Cancer 2011;. © 2011 American Cancer Society.