Local surgery feasibility and safety after carbon ion radiotherapy for primary bone sarcomas.

BACKGROUND: It is known that several complications are caused by local surgery after radiotherapy. Clinical reports that describe the postoperative complications associated with surgery after carbon ion radiotherapy are sparse. This study aimed to elucidate local surgery feasibility after carbon ion radiotherapy specifically for primary bone sarcomas. METHODS: The medical, surgical, and irradiation records of patients who had local surgery at the area irradiated with carbon ion beams between 2004 and 2018 were reviewed retrospectively to evaluate the feasibility and indication of local surgery after CIRT. RESULTS: There were eight patients who had 10 local surgeries at the irradiated sites among the 42 carbon ion radiotherapy patients. There were seven males and one female with a median age of 50 years (range 26-73 years). The reasons for surgery were three for skin toxicity and associated infection, five for bone collapse, and associated implant failure, and two for tumor regrowth. All surgical fields included the area of more than 60 Gy (RBE) irradiated dose. All three surgical cases caused by skin toxicity and associated infection had Grade I wound complication after surgery according to the Clavien-Dindo Classification. CONCLUSION: Local surgery after CIRT appeared feasible in selected patients with primary bone sarcoma, especially for the patients with bone collapse and associated implant failure. However, infection and prescribed irradiation dose at the incision site must be carefully evaluated.

Dedifferentiation in low-grade osteosarcoma: a Japanese Musculoskeletal Oncology Group (JMOG) study.

BACKGROUND: Low-grade osteosarcomas, namely parosteal osteosarcoma (POS) and low-grade central osteosarcoma (LGCOS), occasionally dedifferentiate into high-grade malignancy, referred to as dedifferentiation in low-grade osteosarcoma (DLOS). This study aimed to elucidate the clinicopathologic features of DLOS, which are poorly described to date due to the extreme rarity of the disease. METHODS: A total of 33 patients with DLOS were included. Clinical characteristics, including the diagnostic accuracy of tumor biopsy, multimodal treatments, and clinical course, were retrospectively reviewed. Univariate analysis was performed to identify prognostic factors associated with overall survival (OS) and metastasis-free survival (MFS). RESULTS: The tumor subtypes comprised 10 cases (30.3%) of LGCOS and 23 cases (69.7%) of POS. The timing of dedifferentiation was synchronous in 25 (75.8%) and metachronous in 8 (24.2%) patients. The rates of preoperative diagnosis of DLOS were 40.0% and 65.4% for core needle biopsy and incisional biopsy, respectively. All patients underwent surgery and 25 patients received perioperative chemotherapy. Of the 13 patients who received neoadjuvant chemotherapy, 11 exhibited a poor histological response. The 5-year OS and MFS rates were 88.1% and 77.7%, respectively. Univariate analysis revealed that local recurrence was associated with poor OS (P < 0.01) and MFS (P < 0.01). Perioperative chemotherapy did not affect OS or MFS. CONCLUSIONS: The diagnostic accuracy of tumor biopsy for DLOS was lower than that for bone sarcomas, as reported previously. In contrast to conventional osteosarcomas with high chemosensitivity, both histological responses and survival analysis revealed low efficacy of chemotherapy for DLOS.

Clinical outcomes and significant factors in the survival rate after decompression surgery for patients who were non-ambulatory due to spinal metastases.

BACKGROUND: The development of effective chemotherapy regimens and molecular targeting agents are improving the overall survival rates in patients with cancer. However, patients who are non-ambulatory due to metastatic epidural spinal cord compression (MESCC) may be assessed as unable to tolerate chemotherapy secondary to poor performance status. This means that the ambulatory status of patients with cancer might be significant for survival time. METHODS: We investigated the functional outcomes and factors influencing overall survival in 31 patients who were non-ambulatory due to MESCC and underwent decompression surgery. The functional outcome was determined by the Frankel grading system. RESULT: Twenty-one patients (68%) improved by at least 1 Frankel grade; 17 patients (55%) became ambulatory postoperatively. Most of postoperatively ambulatory patients could undergo postoperative chemotherapy (14/17, 82%). On the other hand, only a few postoperatively non-ambulatory patients could undergo postoperative chemotherapy (2/15, 13%). We observed a complication rate of 35.5% with specific complications including wound infection, pneumonia, and deep vein thrombosis/pulmonary embolus. The median survival duration was 7.0 months. Factors that significantly affected the overall survival in univariate analyses were revised Tokuhashi score (RTS) ≥ 4, postoperative chemotherapy, ambulatory status, and complications (RTS ≥ 4, P < 0.05; postoperative chemotherapy, P < 0.001; ambulatory status, P < 0.001; complications, P < 0.01). CONCLUSIONS: Decompression surgery for patients who are non-ambulatory due to MESCC directly contributes to functional outcomes and may indirectly contribute to overall survival. If non-ambulatory patients who are assessed as unable to tolerate chemotherapy due to poor performance status regain the ability to walk by decompression surgery, they will have a chance to receive postoperative chemotherapy, thereby increasing their chances of prolonging survival. However, postoperative complications may shorten their survival; therefore, we should carefully consider the surgical indications. RTS is useful for judging the surgical indication.

Survival analysis of elderly patients with osteosarcoma.

BACKGROUND: Few studies have described the characteristics and prognostic factors of elderly patients with osteosarcoma. We retrospectively investigated clinico-pathological features and prognostic factors in osteosarcoma patients > 40 years old. METHODS: Patients with high-grade osteosarcoma > 40 years old who were treated at our institutions from 2000 to 2016 were recruited for this study. Information on patient, tumour, and treatment-related factors was collected and statistically analyzed. The median follow-up was 26.5 months (range, 5-139 months) for all patients. RESULTS: Fifty patients (30 males and 20 females) were included. The median age at diagnosis was 59.5 years (range, 41-81 years). The primary lesions were found in the limbs in 32 patients, trunk in 12, and craniofacial bones in six. Primary and secondary osteosarcoma occurred in 41 and 9 patients, respectively. Eight patients exhibited initial distant metastasis. Definitive surgery and chemotherapy were performed in 39 patients each. The rate of good responders after neoadjuvant chemotherapy was 38%. The five year overall survival (OS) rates for all patients and those without distant metastasis at diagnosis were 44.5% and 51.1%, respectively. Multivariate analysis showed that definitive surgery was the only significant prognostic factor in non-metastatic patients. The five year OS and disease-free survival (DFS) rates for non-metastatic patients who received definitive surgery were 64.3% and 60%, respectively. Among these patients, neoadjuvant and/or adjuvant chemotherapy significantly improved both OS and DFS. CONCLUSIONS: Complete surgical resection and intensive chemotherapy should be performed for osteosarcoma patients > 40 years old despite distinct clinicopathological characteristics from those of younger patients.

Therapeutic potential of TAS-115 via c-MET and PDGFRα signal inhibition for synovial sarcoma.

BACKGROUND: The prognosis of synovial sarcoma (SS), an aggressive soft tissue sarcoma, remains poor. We previously reported that c-MET or platelet-derived growth factor receptor α (PDGFRα) signalling pathway is related to SS progression based upon the findings of phospho-receptor tyrosine kinase (RTK) arrays. TAS-115 is a novel c-MET/ vascular endothelial growth factor receptor-targeting tyrosine kinase inhibitor that has been shown to inhibit multiple RTKs. Here we aimed to investigate the therapeutic potential of TAS-115 against SS. METHODS: We first evaluated which signalling pathway was relevant to the viability of three human SS cell lines: Yamato-SS, SYO-1 and HS-SY-II. Next, we assessed the anticancer activity and mechanism of action of TAS-115 in these SS cell lines. Finally, we compared the ability of TAS-115 to inhibit c-MET and PDGFRα phosphorylation with that of pazopanib. RESULTS: We classified the SS cell lines as c-MET-dependent or PDGFRα-dependent based upon the differences in the signalling pathway relevant for growth and/or survival. We also found that c-MET and PDGFRα were the primary activators of both phosphatidylinositol 3-kinase/AKT and mitogen-activated protein kinase pathways in c-MET-dependent and PDGFRα-dependent SS cells, respectively. TAS-115 treatment blocked the phosphorylation of PDGFRα as well as that of c-MET and their downstream effectors, leading to marked growth inhibition in both types of SS cell lines in in vitro and in vivo studies. Furthermore, PDGFRα phosphorylation, on at least four representative autophosphorylation sites, was impeded by TAS-115 equivalently to pazopanib. CONCLUSIONS: These experimental results have demonstrated the significance of c-MET and PDGFRα signalling for growth and/or survival of SS tumours. TAS-115 monotherapy may benefit SS patients whose tumours are dependent upon either c-MET or PDGFRα signalling by functioning as a multiple tyrosine kinase inhibitor to suppress c-MET as well as PDGFRα pathways.

Functional and therapeutic relevance of hepatocyte growth factor/c-MET signaling in synovial sarcoma.

Synovial sarcoma (SS) is an aggressive soft tissue sarcoma with a poor prognosis and, thus, novel therapeutic strategies for SS are urgently required. In the present study, we investigated the functional and therapeutic relevance of hepatocyte growth factor (HGF)/c-MET signaling in SS. Both HGF and c-MET were highly expressed in Yamato-SS cells, resulting in activation of c-MET and its downstream AKT and extracellular signal-regulated kinase signaling pathways, whereas c-MET was expressed but not activated in SYO-1 or HS-SY-II cells. c-MET-activated Yamato-SS cells showed higher anchorage-independent growth ability and less sensitivity to chemotherapeutic agents than did c-MET-inactivated SYO-1 or HS-SY-II cells. INC280, a selective c-MET inhibitor, inhibited growth of Yamato-SS cells both in vitro and in vivo but not that of SYO-1 or HS-SY-II cells. INC280 induced cell cycle arrest and apoptosis, and blocked phosphorylation of c-MET and its downstream effectors in Yamato-SS cells. Co-expression of HGF and c-MET in SS clinical samples correlated with a poor prognosis in patients with SS. Taken together, activation of HGF/c-MET signaling in an autocrine fashion leads to an aggressive phenotype in SS and targeting of this signaling exerts superior antitumor effects on c-MET-activated SS. HGF/c-MET expression status is a potential biomarker for identification of SS patients with a worse prognosis who can benefit from c-MET inhibitors.

Combined targeting of mTOR and c-MET signaling pathways for effective management of epithelioid sarcoma.

BACKGROUND: Epithelioid sarcoma (EpS) is a high-grade malignant soft-tissue sarcoma characterized by local recurrences and distant metastases. Effective treatments for EpS have not been established and thus novel therapeutic approaches against EpS are urgently required. mTOR inhibitors exert antitumor effects on several malignancies but AKT reactivation by mTOR inhibition attenuates the antitumor effects of mTOR inhibitors. This reactivation is receptor tyrosine kinase (RTK)-dependent due to a release of negative feedback inhibition. We found that c-MET was the most highly activated RTK in two human EpS cell lines, Asra-EPS and VAESBJ. Here we investigated the functional and therapeutic relevance of mTOR and/or c-MET signaling pathways in EpS both in vitro and in vivo. METHODS: We first examined the effects of an mTOR inhibitor, RAD001 (everolimus), on cell proliferation, cell cycle, AKT/mTOR signaling, and xenograft tumor growth in EpS cell lines. Next, we determined whether RAD001-induced AKT reactivation was blocked by silencing of c-MET or treatment with a selective c-MET inhibitor, INC280. Finally, we evaluated the antitumor effects of RAD001 combined with INC280 on EpS cell lines compared with either single agent or control in vitro and in vivo. RESULTS: Constitutive AKT phosphorylation was observed in Asra-EPS and VAESBJ cells. RAD001 suppressed EpS cell growth by inducing cell cycle arrest but enhanced AKT phosphorylation, which resulted in intrinsic resistance to mTOR inhibitors. In both EpS cell lines, RAD001-induced AKT phosphorylation was dependent on c-MET signaling. INC280 inhibited phosphorylation of c-MET and its downstream molecules, and decreased RAD001-induced phosphorylation of both AKT and ERK in EpS. Compared with a single agent or control, the combination of RAD001 and INC280 exerted superior antitumor effects on the growth of EpS cell lines in vitro and in vivo. CONCLUSIONS: Targeting of mTOR and c-MET signaling pathways significantly abrogates the growth of EpS in preclinical models and may be a promising therapeutic approach for patients with EpS.

Mesoporous hydrogel electrodes with flexible frameworks exhibiting enhanced mass transport for the oxygen evolution reaction.

Mesoporous hydrogel electrodes with unique flexible mesopores surrounded by CoOOH nanosheets were prepared via the electrochemical deposition of hybrid cobalt hydroxide nanosheets, exhibiting high oxygen evolution reaction activity at a high current density owing to the enhanced mass transport of oxygen molecules.

Targeting the Clear Cell Sarcoma Oncogenic Driver Fusion Gene EWSR1::ATF1 by HDAC Inhibition.

Clear cell sarcoma (CCS), a rare but extremely aggressive malignancy with no effective therapy, is characterized by the expression of the oncogenic driver fusion gene EWSR1::ATF1. In this study, we performed a high-throughput drug screening, finding that the histone deacetylase inhibitor vorinostat exerted an antiproliferation effect with the reduced expression of EWSR1::ATF1. We expected the reduced expression of EWSR1::ATF1 to be due to the alteration of chromatin accessibility; however, assay for transposase-accessible chromatin using sequencing and a cleavage under targets and release using nuclease assay revealed that chromatin structure was only slightly altered, despite histone deacetylation at the EWSR1::ATF1 promoter region. Alternatively, we found that vorinostat treatment reduced the level of BRD4, a member of the bromodomain and extraterminal motif protein family, at the EWSR1::ATF1 promoter region. Furthermore, the BRD4 inhibitor JQ1 downregulated EWSR1::ATF1 according to Western blotting and qPCR analyses. In addition, motif analysis revealed that vorinostat treatment suppressed the transcriptional factor SOX10, which directly regulates EWSR1::ATF1 expression and is involved in CCS proliferation. Importantly, we demonstrate that a combination therapy of vorinostat and JQ1 synergistically enhances antiproliferation effect and EWSR1::ATF1 suppression. These results highlight a novel fusion gene suppression mechanism achieved using epigenetic modification agents and provide a potential therapeutic target for fusion gene-related tumors. Significance: This study reveals the epigenetic and transcriptional suppression mechanism of the fusion oncogene EWSR1::ATF1 in clear cell sarcoma by histone deacetylase inhibitor treatment as well as identifying SOX10 as a transcription factor that regulates EWSR1::ATF1 expression.

Principles of Self-Repairing Ability of Tripodal Ligand-Stabilized Hybrid Cobalt Hydroxide Nanosheets for Alkaline Water Electrolysis.

Self-repairing catalysts are promising new materials for achieving long lifetime of alkaline water electrolyzers powered by renewable energy. Catalytic nanoparticles dispersed in an electrolyte were deposited on the anode to repair a catalyst layer by electrolysis. A hybrid cobalt hydroxide nanosheet modified with tris(hydroxymethyl)aminomethane on the surface (Co-ns) was used as a catalyst. Assuming a pseudo-first-order process, the rate constant of an electrochemical deposition was linearly correlated with the electrode potential during electrolysis. Thus, it is expected that the repair of the catalyst is automatically controlled by changes in the oxygen evolution reaction (OER) overpotential. The essential step of the electrochemical deposition was the anodic oxidation of Co2+ to Co3+ . Surface modification of Co-ns protects Co2+ against the autooxidation of Co2+ caused by the dissolved oxygen. The redox properties and organic modification of Co-ns make them well-suited for the self-repairing of anode catalysts.

Impact of Surgery and Chemotherapy on Metastatic Extrauterine Leiomyosarcoma.

Background: Few studies have described the characteristics and prognostic factors of patients with metastatic extrauterine leiomyosarcoma (euLMS). Therefore, we retrospectively investigated the clinicopathological features, clinical outcomes, and prognostic factors of patients with euLMS. Methods: We recruited 61 patients with metastatic euLMS treated from 2006 to 2020 and collected and statistically analyzed information on patient-, tumor-, and treatment-related factors. The median follow-up period was 21.1 months. Results: Sixty-one patients with euLMS and a median age of 59 years were included. Furthermore, their five-year overall survival (OS) rate was 38.3%. Univariate analysis revealed that primary tumor size >10 cm, synchronous metastasis, initial metastatic sites >1, and no metastasectomy with curative intent were significantly associated with poor OS rate. Multivariate analysis identified primary tumor size >10 cm as an independent prognostic factor for poor OS. Among 24 patients who received metastasectomy with curative intent, the interval from the initial diagnosis to development of metastasis ≤6 months was significantly correlated with unfavorable OS. Among 37 patients who did not receive metastasectomy, chemotherapy after metastasis development was significantly related to better OS. Conclusions: Complete metastasectomy should be considered for metastatic euLMS treatment. Moreover, chemotherapy could prolong survival in patients with metastasis who are ineligible for metastasectomy.

Clinical Outcomes and Prognostic Factors for Patients with Malignant Peripheral Nerve Sheath Tumour.

INTRODUCTION: Few studies have described the characteristics and prognostic factors of patients with malignant peripheral nerve sheath tumour (MPNST). In this study, we retrospectively investigated the clinicopathological features, clinical outcomes, and prognostic factors of these patients. Patients and Methods. We recruited patients with MPNST who were treated at our institutions from 1991 to 2020. We collected and statistically analysed information on patient-, tumour-, and treatment-related factors. The median follow-up period was 61 months (range, 1-335.8 months). RESULTS: A total of 60 patients (31 males, 29 females) with a median age of 55 years (range, 8-84 years) at initial diagnosis were included. The median tumour size was 7 cm (range, 1.6-30 cm) in the greatest dimension. The 5-year overall survival (OS) rate of all patients was 69.5%. Univariate analysis revealed that large-sized tumour, metastasis at diagnosis, and no surgery of the primary tumour were significantly associated with patients with worse OS. Multivariate analysis identified surgery of the primary tumour as an independent prognostic factor for improved OS. Among patients with localised disease at diagnosis who underwent surgery of the primary tumour at our institutions, the 5-year OS, local recurrence-free survival (LRFS), and metastasis-free survival (MFS) rates were 81.1%, 78.2%, and 70.3%, respectively. Univariate analysis revealed that positive surgical margin was significantly correlated with unfavourable OS and LRFS, and high grade was a poor prognostic indicator for MFS. CONCLUSION: Complete surgical resection with negative surgical margins is necessary for a successful MPNST treatment. Multidisciplinary management of MPNST with aggressive features is important for optimising patient outcomes.

18F-Fluorodeoxyglucose Positron Emission Tomography Is Useful in the Evaluation of Prognosis in Retroperitoneal Sarcoma.

Background: Retroperitoneal sarcomas are rare neoplasms that occur in the retroperitoneum. Complete surgical resection is the only effective treatment option. The prediction of prognosis by histological diagnosis has not yet been established. The purpose of this study was to identify the usefulness of [18-F] fluorodeoxyglucose (FDG) positron emission tomography (PET) imaging for validating the prognosis of retroperitoneal sarcoma (RPS) established by histological diagnosis. Methods: We retrospectively reviewed 201 patients with RPS treated at the Osaka International Cancer Institute between 2010 and 2021. We extracted the clinical data, including standardized uptake values (SUVs), evaluated with FDG-PET, and statistically analyzed the data. Results: The median age of patients was 64 years (range, 31-85 years). A total of 101 (50.2%) patients were men, and 100 (49.8%) were women. Surgical resection was performed in 155 (77.1%) patients. On histological analysis, 75 (37.3%), 52 (25.9%), and 29 (14.4%) patients were diagnosed with dedifferentiated liposarcoma, well-differentiated liposarcoma, and leiomyosarcoma, respectively. The median survival time for patients with high maximum SUV (SUVmax) (≥4) or low SUVmax (<4) was 275.8 months and 79.5 months, respectively. Furthermore, among the patients with dedifferentiated liposarcoma, the overall survival rate for patients with high SUVmax (≥4) was significantly lower than that of those with low SUVmax (<4). Conclusions: The present study demonstrated that SUVmax calculated with FDG-PET was useful as a prognostic factor in RPS, especially in dedifferentiated liposarcoma and Grade2 RPS. To devise a treatment strategy for RPS, SUVmax during FDG-PET scan may be considered for clinical assessment.

TAS-115 inhibits PDGFRα/AXL/FLT-3 signaling and suppresses lung metastasis of osteosarcoma.

Osteosarcoma is the most common malignant bone tumor in adolescence and childhood. Metastatic osteosarcoma has a poor prognosis with an overall 5-year survival rate of approximately 20%. TAS-115 is a novel multiple receptor tyrosine kinase inhibitor that is currently undergoing clinical trials. Using the mouse highly lung-metastatic osteosarcoma cell line, LM8, we showed that TAS-115 suppressed the growth of subcutaneous grafted tumor and lung metastasis of osteosarcoma at least partially through the inhibition of platelet-derived growth factor receptor alpha, AXL, and Fms-like tyrosine kinase 3 phosphorylation. We also show that these signaling pathways are activated in various human osteosarcoma cell lines and are involved in proliferation. Our results suggest that TAS-115 may have potential for development into a novel treatment for metastatic osteosarcoma.

Eribulin Suppresses Clear Cell Sarcoma Growth by Inhibiting Cell Proliferation and Inducing Melanocytic Differentiation Both Directly and Via Vascular Remodeling.

Clear cell sarcoma (CCS) is a rare but chemotherapy-resistant and often fatal high-grade soft-tissue sarcoma (STS) characterized by melanocytic differentiation under control of microphthalmia-associated transcription factor (MITF). Eribulin mesilate (eribulin) is a mechanistically unique microtubule inhibitor commonly used for STS treatment, particularly liposarcoma and leiomyosarcoma. In this study, we examined the antitumor efficacy of eribulin on four human CCS cell lines and two mouse xenograft models. Eribulin inhibited CCS cell proliferation by inducing cell-cycle arrest and apoptosis, shrunk CCS xenograft tumors, and increased tumor vessel density. Eribulin induced MITF protein upregulation and stimulated tumor cell melanocytic differentiation through ERK1/2 inactivation (a MITF negative regulator) in vitro and in vivo Moreover, tumor reoxygenation, probably caused by eribulin-induced vascular remodeling, attenuated cell growth and inhibited ERK1/2 activity, thereby upregulating MITF expression and promoting melanocytic differentiation. Finally, downregulation of MITF protein levels modestly debilitated the antiproliferative effect of eribulin on CCS cells. Taken together, eribulin suppresses CCS through inhibition of cell proliferation and promotion of tumor differentiation by acting both directly on tumor cells and indirectly through tumor reoxygenation.

Author Correction: Establishment of a novel human CIC-DUX4 sarcoma cell line, Kitra-SRS, with autocrine IGF-1R activation and metastatic potential to the lungs.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Establishment of a novel human CIC-DUX4 sarcoma cell line, Kitra-SRS, with autocrine IGF-1R activation and metastatic potential to the lungs.

Approximately 60-70% of EWSR1-negative small blue round cell sarcomas harbour a rearrangement of CIC, most commonly CIC-DUX4. CIC-DUX4 sarcoma (CDS) is an aggressive and often fatal high-grade sarcoma appearing predominantly in children and young adults. Although cell lines and their xenograft models are essential tools for basic research and development of antitumour drugs, few cell lines currently exist for CDS. We successfully established a novel human CDS cell line designated Kitra-SRS and developed orthotopic tumour xenografts in nude mice. The CIC-DUX4 fusion gene in Kitra-SRS cells was generated by t(12;19) complex chromosomal rearrangements with an insertion of a chromosome segment including a DUX4 pseudogene component. Kitra-SRS xenografts were histologically similar to the original tumour and exhibited metastatic potential to the lungs. Kitra-SRS cells displayed autocrine activation of the insulin-like growth factor 1 (IGF-1)/IGF-1 receptor (IGF-1R) pathway. Accordingly, treatment with the IGF-1R inhibitor, linsitinib, attenuated Kitra-SRS cell growth and IGF-1-induced activation of IGF-1R/AKT signalling both in vitro and in vivo. Furthermore, upon screening 1134 FDA-approved drugs, the responses of Kitra-SRS cells to anticancer drugs appeared to reflect those of the primary tumour. Our model will be a useful modality for investigating the molecular pathology and therapy of CDS.

Endoprosthetic Reconstruction for a Displaced Atypical Femoral Fracture in a Cancer Patient with Poor Prognosis.

Zoledronate or denosumab treatment is beneficial for cancer patients with bone metastasis. However, each agent may trigger atypical femoral fractures. Incomplete atypical femoral fractures can be successfully treated with prophylactic intramedullary nailing. On the other hand, intramedullary nailing for displaced atypical femoral fractures occasionally causes problems with regard to bone healing, resulting in long-term treatment. In cancer patients with poor prognosis who experience atypical femoral fractures, improvement in activities of daily living should be the priority. Thus, we performed endoprosthetic reconstruction for a displaced atypical femoral fracture in a breast cancer patient with poor prognosis to enable walking in the early stage after the operation. Two weeks after the operation, she could successfully walk. The postoperative Musculoskeletal Tumor Society score was 47%, and it had improved to almost the preoperative level before injury (50%). In conclusion, endoprosthetic reconstruction for displaced atypical femoral fractures may be a first-line treatment approach to acquire early postoperative walking ability for improving activities of daily living in cancer patients with poor prognosis.

Trabectedin is a promising antitumor agent potentially inducing melanocytic differentiation for clear cell sarcoma.

Clear cell sarcoma is an aggressive soft tissue sarcoma and highly resistant to conventional chemotherapy and radiation therapy. This devastating disease is defined by EWSR1-ATF1 fusion gene resulting from chromosomal translocation t(12;22)(q13;q12) and characterized by melanocytic differentiation. A marine-derived antineoplastic agent, trabectedin, inhibits the growth of myxoid liposarcoma and Ewing sarcoma by causing adipogenic differentiation and neural differentiation, respectively. In this study, we examined the antitumor effects and mechanism of action of trabectedin on human clear cell sarcoma cell lines. We showed that trabectedin decreased the cell proliferation of five clear cell sarcoma cell lines in a dose-dependent manner in vitro and reduced tumor growth of two mouse xenograft models. Flow cytometry and immunoblot analyses in vitro and immunohistochemical analysis in vivo revealed that trabectedin-induced G2/M cell cycle arrest and apoptosis. Furthermore, trabectedin increased the expression of melanocytic differentiation markers along with downregulation of ERK activity in vitro and the rate of melanin-positive cells in vivo. These results suggest that trabectedin has potent antitumor activity against clear cell sarcoma cells by inducing cell cycle arrest, apoptosis, and, in part, by promoting melanocytic differentiation through inactivation of ERK signaling. Our present study indicates that trabectedin is a promising differentiation-inducing agent for clear cell sarcoma.