Prevalence of Metastasis at Diagnosis of Osteosarcoma: An International Comparison

Identification of potential genes associated with metastasis in osteosarcoma: an integrated bioinformatics analysis

This study aims to identify the potential genes, pathways, and tumor immune microenvironment that might be involved in the metastasis process of osteosarcoma (OS). The GEO2R tool was deployed to screen two datasets obtained from the Gene Expression Omnibus (GEO) database (GSE87624 and GSE85537). Integrated bioinformatic analyses were then performed to investigate Gene Ontology, potential pathways, protein-protein network interaction, core hub genes, genetic alterations, and immune cell infiltration. The hub gene expression levels were validated utilizing another dataset (GSE14329) and patient prognosis was validated using the GDC-TARGET OS dataset. Our analysis identified 263 differentially expressed genes (DEGs), predominantly associated with the PI3K-AKT signaling pathway. Analysis using Cytoscape based on DEGs revealed five validated core hub genes including COL6A1, MMP2, POSTN, TAGLN, and THY1. Additionally, TAGLN and THY1 have a significant association (P = 0.008) (P = 0.03) with unfavorable outcomes in osteosarcoma patients. This study unveiled that TAGLN and THY1 were associated with metastasis and poor prognosis in OS.

Identification of telomere-related gene subtypes and prognostic signatures in osteosarcoma

Background

Osteosarcoma (OS) is the prevalent primary bone cancer, with a high proclivity for local invasion and metastasis. Previous studies have indicated that telomeres are closely related to prognosis of cancer, but the significance of telomere-related features in OS remains uncertain. Thus, the goal of this work is to identified telomere-related subtypes based on the telomere-related genes (TRGs).

Methods

The data of OS was collected from TARGET and Gene Expression Omnibus databases. Firstly, we identified the subtypes mediated by TRGs in OS. Subsequently, we analyzed the immune characteristics of telomeres-related subtypes in OS. Moreover, we built a telomere-related signature via univariate and LASSO Cox regression analyses, and analyzed the correlation of telomere-related signature with TME. Finally, we analyzed the expression of hub TRGs in OS.

Results

We discovered that TRGs could distinguish OS patients into two telomeres-related subtypes (C1 and C2). The survival rate of OS patients in C2 was inferior to that of patients in C1. The scores of stromal, immune and ESTIMATES were observably increased, and tumor purity was decreased in C1 subtypes compared to C2 subtypes. Differentially expressed genes between C1 and C2 were highly enriched in immune-related pathways. Moreover, C1 and C2 subtypes had different immune characteristic. Furthermore, a telomere prognostic model including six genes (PDK2, PPARG, MORC4, SP110, TERT and MAP3K5) was established to predict the prognosis of OS patients. High-risk group was correlated with inferior prognosis of OS patients, and risk score model was correlated with TME. Finally, we discovered that expression of PDK2, PPARG, MORC4, SP110, TERT and MAP3K5 was significantly decreased in OS cells.

Conclusion

In conclusion, our study has uncovered the importance of TRGs in defining distinct subtypes of OS with different survival outcomes and immune contexts. The telomere-related signature we developed may serve as a valuable tool for prognosis prediction and could inform future therapeutic strategies targeting the TME in OS.

IGFBP5 in osteosarcoma tumorigenesis: Gene expression profile among metastatic and non-metastatic patients

Osteosarcoma (OS) is the most frequent primary malignant bone tumor among children and adolescents, with a peak of incidence in the second decade of life. The presence of metastasis at diagnosis in OS patients significantly decreases the chances of survival and new therapy approaches are needed. The IGFBP5 gene is related to osteoblasts metabolism and some studies have pointed out a role of its low expressions in OS development and metastasis. In this study, we aimed to establish an IGFBP5 gene expression profile among metastatic and non-metastatic OS patients throughout the treatment and development of the disease. Fresh-frozen tumor samples were obtained from 40 patients admitted to treatment at the Pediatric Oncology Institute (IOP/GRAACC/UNIFESP) and divided by clinical status: metastatic or non-metastatic disease. For each patient, samples before and after chemotherapy treatment were obtained, as well as metastasis and lung tissue surrounding metastasis samples from the metastatic patients. A quantitative real-time PCR was used to investigate IGFBP5 expression. Our analyses demonstrate that non-metastatic patients presented lower IGFBP5 expression in their pre-chemotherapy samples compared with metastatic patients, suggesting that low expressions of this gene could help triggering the OS tumorigenesis but that its action alone is not sufficient to activate the metastatic process. Heterogeneity in IGFBP5 expressions within groups was also seen. We observed that IGFBP5 and two MAPK genes, a downstream pathway in the IGFBP5 axis, are differentially expressed in OS samples of non-metastatic patients. Further investigation about these genes' modulations might lead to a better understanding of metastasis development in OS.

Exosome-mediated delivery of siRNA molecules in cancer therapy: triumphs and challenges

The discovery of novel and innovative therapeutic strategies for cancer treatment and management remains a major global challenge. Exosomes are endogenous nanoscale extracellular vesicles that have garnered increasing attention as innovative vehicles for advanced drug delivery and targeted therapy. The attractive physicochemical and biological properties of exosomes, including increased permeability, biocompatibility, extended half-life in circulation, reduced toxicity and immunogenicity, and multiple functionalization strategies, have made them preferred drug delivery vehicles in cancer and other diseases. Small interfering RNAs (siRNAs) are remarkably able to target any known gene: an attribute harnessed to knock down cancer-associated genes as a viable strategy in cancer management. Extensive research on exosome-mediated delivery of siRNAs for targeting diverse types of cancer has yielded promising results for anticancer therapy, with some formulations progressing through clinical trials. This review catalogs recent advances in exosome-mediated siRNA delivery in several types of cancer, including the manifold benefits and minimal drawbacks of such innovative delivery systems. Additionally, we have highlighted the potential of plant-derived exosomes as innovative drug delivery systems for cancer treatment, offering numerous advantages such as biocompatibility, scalability, and reduced toxicity compared to traditional methods. These exosomes, with their unique characteristics and potential for effective siRNA delivery, represent a significant advancement in nanomedicine and cancer therapeutics. Further exploration of their manufacturing processes and biological mechanisms could significantly advance natural medicine and enhance the efficacy of exosome-based therapies.

The Effect of Socioeconomic Status and Race/Ethnicity on the Risk of Presenting With Advanced Stage at Diagnosis in Embryonal Tumors

We evaluated whether socioeconomic status (SES), race/ethnicity, and their interaction were associated with the presentation of advanced stage at diagnosis in embryonal tumors. Children 0 to 19 years of age diagnosed with embryonal tumors between 2006 and 2018 were identified from the US Surveillance, Epidemiology, and End Results program database specialized with Census Tract SES/Rurality. SES quintile was derived from a composite index for census tracts. We performed logistic regression to estimate odds ratios (ORs) and 95% confidence intervals by SES and race/ethnicity, adjusting for sex, age, and diagnosis year. Overall, no significant associations were found between either SES or race/ethnicity and the risk of presenting with advanced stage at diagnosis, although patterns of risk reductions were observed in atypical teratoid/rhabdoid tumors and embryonal rhabdomyosarcoma with increasing SES. In the stratified analysis, decreased odds of presenting with advanced-stage embryonal rhabdomyosarcoma were observed for Hispanics with higher SES (OR: 0.24, 95% Confidence Interval: 0.08-0.75) compared with Hispanics with lower SES. Future studies incorporating individual-level SES, cancer-specific staging information, and potential demographic, clinical, epidemiological, and genetic risk factors are warranted to confirm our findings.

A Rare Outcome of a Case of Medullary Osteosarcoma of the Femur in Ghana

Introduction

Osteosarcoma is a malignant mesenchymal neoplasm in which the tumor cells produce defective and immature bone (osteoid). The risk factors for developing the disease include: Patients with hereditary retinoblastoma and germline mutations of the p53 tumor suppressor gene.

Case Report

A 32-year old male presented with pain and swelling of the left thigh of 9 months duration. The pain was progressive, excruciating, worse at night, and unresponsive to paracetamol with moderate weight loss. He had sought treatment from a traditional bonesetter 6 months before presentation and had no improvement of the symptoms.

Conclusion

In medullary osteosarcoma of the femur, where there is extracomparmental disease with no distant metastasis, clinically and radiologically, radical tumor resection with a free oncological margin increases survival of the patient up to 7 years.

Niclosamide: A career builder

My contribution to honoring Professor Kinam Park celebrates and resonates with his scholarly career in drug delivery, his commitment to encouraging the next generation(s), and his efforts to keep us focused on clinically effective formulations. To do this I take as my example, niclosamide, a small molecule protonophore that, uniquely, can "target" all cell membranes, both plasma and organelle. As such, it acts upstream of many cell pathways and so has the potential to affect many of the essential events that a cell, and particularly a diseased cell or other entities like a virus, use to stay alive and prosper. Literature shows that it has so far been discovered to positively influence (at least): cancer, bacterial and viral infection, metabolic diseases such as Type II diabetes, NASH and NAFLD, artery constriction, endometriosis, neuropathic pain, rheumatoid arthritis, sclerodermatous graft-versus-host disease, systemic sclerosis, Parkinson's, and COPD. With such a fundamental action and broad-spectrum activity, I believe that studying niclosamide in all its manifestations, discovering if and to what extent it can contribute positively to disease control (and also where it can't), formulating it as effective therapeutics, and testing them in preclinical and clinical trials is a career builder for our next generation(s). The article is divided into two parts: Part I introduces niclosamide and other proton shunts mainly in cancer and viral infections and reviews an exponentially growing literature with some concepts and physicochemical properties that lead to its proton shunt mechanism. Part II focuses on repurposing by reformulation of niclosamide. I give two examples of "carrier-free formulations", - one for cancer (as a prodrug therapeutic of niclosamide stearate for i.v. and other administration routes, exemplified by our recent work on Osteosarcoma in mice and canine patients), and the other as a niclosamide solution formulation (that could provide the basis for a preventative nasal spray and early treatment option for COVID19 and other respiratory virus infections). My goal is to excite and enthuse, encourage, and motivate all involved in the drug development and testing process in academia, institutes, and industry, to learn more about this interesting molecule and others like it. To enable such endeavors, I give many proposed ideas throughout the document, that have been stimulated and inspired by gaps in the literature, urgent needs in disease, and new studies arising from our own work. The hope is that, by reading through this document and studying the suggested topics and references, the drug delivery and development community will continue our lineage and benefit from our legacy to achieve niclosamide's potential as an effective contributor to the treatment and control of many diseases and conditions.

Osteosarcoma cells exhibit functional interactions with stromal cells, fostering a lung microenvironment conducive to the establishment of metastatic tumor cells

BACKGROUND

Osteosarcoma (OS) stands out as the most common bone tumor, with approximately 20% of the patients receiving a diagnosis of metastatic OS at their initial assessment. A significant challenge lies in the frequent existence of undetected metastases during the initial diagnosis. Mesenchymal stem cells (MSCs) possess unique abilities that facilitate tumor growth, and their interaction with OS cells is crucial for metastatic spread.

METHODS AND RESULTS

We demonstrated that, in vitro, MSCs exhibited a heightened migration response toward the secretome of non-metastatic OS cells. When challenged to a secretome derived from lungs preloaded with OS cells, MSCs exhibited greater migration toward lungs colonized with metastatic OS cells. Moreover, in vivo, MSCs displayed preferential migratory and homing behavior toward lungs colonized by metastatic OS cells. Metastatic OS cells, in turn, demonstrated an increased migratory response to the MSCs' secretome. This behavior was associated with heightened cathepsin D (CTSD) expression and the release of active metalloproteinase 2 (MMP2) by metastatic OS cells.

CONCLUSIONS

Our assessment focused on two complementary tumor capabilities crucial to metastatic spread, emphasizing the significance of inherent cell features. The findings underscore the pivotal role of signaling integration within the niche, with a complex interplay of migratory responses among established OS cells in the lungs, prometastatic OS cells in the primary tumor, and circulating MSCs. Pulmonary metastases continue to be a significant factor contributing to OS mortality. Understanding these mechanisms and identifying differentially expressed genes is essential for pinpointing markers and targets to manage metastatic spread and improve outcomes for patients with OS.

Primary Multi-Systemic Metastases in Osteosarcoma: Presentation, Treatment, and Survival of 83 Patients of the Cooperative Osteosarcoma Study Group

BACKGROUND

To evaluate patient and tumour characteristics, treatment, and their impact on survival in patients with multi-systemic metastases at initial diagnosis of high-grade osteosarcoma. Precedure: Eighty-three consecutive patients who presented with multi-systemic metastases at initial diagnosis of high-grade osteosarcoma were retrospectively reviewed. In cases of curative intent, the Cooperative Osteosarcoma Study Group recommended surgical removal of all detectable metastases in addition to complete resection of the primary tumour and chemotherapy.

RESULTS

Eighty-three eligible patients (1.8%) were identified among a total of 4605 individuals with high-grade osteosarcoma. Nine (10.8%) of these achieved complete surgical remission, of whom seven later had recurrences. The median follow-up time was 12 (range, 1-165) months for all patients. Actuarial event-free survival after 1, 2, and 5 years was 9.6 ± 3.2%, 1.4 ± 1.4%, and 1.4 ± 1.4%, and overall survival was 54.0 ± 5.6%, 23.2 ± 4.9%, and 8.7 ± 3.3%. In univariate analyses, elevated alkaline phosphatase before chemotherapy, pleural effusion, distant bones as metastatic sites, and more than one bone metastasis were negative prognostic factors. Among treatment-related factors, the microscopically complete resection of the primary tumour, a good response to first-line chemotherapy, the macroscopically complete resection of all affected tumour sites, and local treatment (surgery ± radiotherapy) of all bone metastases were associated with better outcomes. Tumour progression under first-line treatment significantly correlated with shorter survival times.

CONCLUSION

The outlook for patients with multi-systemic primary metastases from osteosarcoma remains very poor. The utmost importance of surgical resection of all tumour sites was confirmed. For unresectable bone metastases, radiotherapy might be considered. In the patient group studied, standard chemotherapy was often insufficiently effective. In the case of such advanced disease, alternative treatment options are urgently required.

Exploring the role of lncrna neat1 knockdown in regulating apoptosis across multiple cancer types: A review

Long non-coding RNAs (lncRNAs) have emerged as pivotal regulators of gene expression, contributing significantly to a diverse range of cellular processes, including apoptosis. One such lncRNA is NEAT1, which is elevated in several types of cancer and aid in cancer growth. However, recent studies have also demonstrated that the knockdown of NEAT1 can inhibit cancer cells proliferation, movement, and infiltration while enhancing apoptosis. This article explores the function of lncRNA NEAT1 knockdown in regulating apoptosis across multiple cancer types. We explore the existing understanding of NEAT1's involvement in the progression of malignant conditions, including its structure and functions. Additionally, we investigate the molecular mechanisms by which NEAT1 modulates the cell cycle, cellular proliferation, apoptosis, movement, and infiltration in diverse cancer types, including acute myeloid leukemia, breast cancer, cervical cancer, colorectal cancer, esophageal squamous cell carcinoma, glioma, non-small cell lung cancer, ovarian cancer, prostate cancer, and retinoblastoma. Furthermore, we review the recent studies investigating the therapeutic potential of NEAT1 knockdown in cancer treatment. Targeting the lncRNA NEAT1 presents a promising therapeutic approach for treating cancer. It has shown the ability to suppress cancer cell proliferation, migration, and invasion while promoting apoptosis in various cancer types.

Implementing precision oncology for sarcoma patients: the CCCLMUmolecular tumor board experience

PURPOSE

Due to poor outcomes and limited treatment options, patients with advanced bone and soft tissue sarcomas (BS/STS) may undergo comprehensive molecular profiling of tumor samples to identify possible therapeutic targets. The aim of this study was to determine the impact of routine molecular profiling in the setting of a dedicated precision oncology program in patients with BS/STS in a German large-volume sarcoma center.

METHODS

92 BS/STS patients who received comprehensive genomic profiling (CGP) and were subsequently discussed in our molecular tumor board (MTB) between 2016 and 2022 were included. Patient records were retrospectively reviewed, and the clinical impact of NGS-related findings was analyzed.

RESULTS

89.1% of patients had received at least one treatment line before NGS testing. At least one molecular alteration was found in 71 patients (82.6%). The most common alterations were mutations in TP53 (23.3% of patients), followed by PIK3CA and MDM2 mutations (9.3% each). Druggable alterations were identified, and treatment recommended in 32 patients (37.2%). Of those patients with actionable alterations, ten patients (31.2%) received personalized treatment and six patients did benefit from molecular-based therapy in terms of a progression-free survival ratio (PFSr) > 1.3.

CONCLUSION

Our single-center experience shows an increasing uptake of next-generation sequencing (NGS) and highlights current challenges of implementing precision oncology in the management of patients with BS/STS. A relevant number of patients were diagnosed with clinically actionable alterations. Our results highlight the potential benefit of NGS in patients with rare cancers and currently limited therapeutic options.

Unveiling the prognostic implications of RPLP1 upregulation in osteosarcoma

Osteosarcoma, a malignant bone tumor characterized by a high rate of metastasis and poor survival, presents a critical need for identifying novel biomarkers associated with metastasis. In this study, we conducted an extensive analysis utilizing transcriptional and clinical data sourced from databases such as GEO, TCGA, CCLE, R2, and Xena. And we discovered that Ribosomal protein LP1 (RPLP1) ranked among the top upregulated genes in relation to osteosarcoma metastasis. Notably, RPLP1 exhibited significant expression in both osteosarcoma cell lines and patient samples. Moreover, multiple osteosarcoma studies revealed a strong correlation between RPLP1 overexpression and worse metastasis-free survival as well as overall survival. Additionally, we observed a consistent association between dysregulation of RPLP1 and reduced overall survival across various tumor types. Knocking down of RPLP1 led to the down-regulation of MYL5 and functional enrichment toward cell cycle and cellular interaction. Based on these findings, we propose that RPLP1 has the potential to serve as a prognostic biomarker, indicating increased metastasis and worse survival outcomes in osteosarcoma. These insights contribute to a better understanding of the disease and may pave the way for future research and therapeutic approaches.

A TLR4 Agonist Induces Osteosarcoma Regression by Inducing an Antitumor Immune Response and Reprogramming M2 Macrophages to M1 Macrophages

Osteosarcoma (OsA) has limited treatment options and stagnant 5-year survival rates. Its immune microenvironment is characterized by a predominance of tumor-associated macrophages (TAMs), whose role in OsA progression remain unclear. Nevertheless, immunotherapies aiming to modulate macrophages activation and polarization could be of interest for OsA treatment. In this study, the antitumor effect of a liposome-encapsulated chemically detoxified lipopolysaccharide (Lipo-MP-LPS) was evaluated as a therapeutic approach for OsA. Lipo-MP-LPS is a toll-like receptor 4 (TLR4) agonist sufficiently safe and soluble to be IV administered at effective doses. Lipo-MP-LPS exhibited a significant antitumor response, with tumor regression in 50% of treated animals and delayed tumor progression in the remaining 50%. The agent inhibited tumor growth by 75%, surpassing the efficacy of other immunotherapies tested in OsA. Lipo-MP-LPS modulated OsA's immune microenvironment by favoring the transition of M2 macrophages to M1 phenotype, creating a proinflammatory milieu and facilitating T-cell recruitment and antitumor immune response. Overall, the study demonstrates the potent antitumor effect of Lipo-MP-LPS as monotherapy in an OsA immunocompetent model. Reprogramming macrophages and altering the immune microenvironment likely contribute to the observed tumor control. These findings support the concept of immunomodulatory approaches for the treatment of highly resistant tumors like OsA.

Multimodal evaluation of osteosarcoma choroidal metastasis

BACKGROUND

Osteosarcoma (OS) is the most common primary bone carcinoma. Adulthood most frequent intraocular malignant tumor is choroidal metastasis; however, these are rarely related to sarcomas. There are only two OS-related choroidal metastasis cases reported in the literature, both prior to 1970.

CASE PRESENTATION

A 20-year-old man with a history of tibial OS, right leg amputation, and lung and brain metastases, presented with decreased vision in his right eye (OD). Ophthalmic examination revealed a best-corrected visual acuity of hand movements and a large, posterior pole, nodular, subretinal mass, with associated fluid. B-scan revealed a heterogeneous lump, with medium/high reflectivity, and a height-to-base ratio (HBR) of 1-1.2, approximately. Computerized tomography (CT) scan showed a hyperdense and contrast-enhanced mass, while on magnetic resonance imaging (MRI) the lesion appeared T1-isointense and T2-hypointense.

CONCLUSION

Choroidal OS metastasis can appear as a pink nodule with high HBR and intralesional hyperreflective deposits. Sudden visual changes in individuals with OS-related systemic metastatic disease should be monitored closely by ophthalmology and oncology jointly.

A chimeric human/dog-DNA vaccine against CSPG4 induces immunity with therapeutic potential in comparative preclinical models of osteosarcoma

The high mortality rate of osteosarcoma (OSA) patients highlights the requirement of alternative strategies. The young age of patients, as well as the rarity and aggressiveness of the disease, limits opportunities for the robust testing of novel therapies, suggesting the need for valuable preclinical systems. Having previously shown the overexpression of the chondroitin sulfate proteoglycan (CSPG)4 in OSA, herein the functional consequences of its downmodulation in human OSA cells were evaluated in vitro, with a significant impairment of cell proliferation, migration, and osteosphere generation. The potential of a chimeric human/dog (HuDo)-CSPG4 DNA vaccine was explored in translational comparative OSA models, including human xenograft mouse models and canine patients affected by spontaneous OSA. The adoptive transfer of HuDo-CSPG4 vaccine-induced CD8+ T cells and sera in immunodeficient human OSA-bearing mice delayed tumor growth and metastasis development. HuDo-CSPG4 vaccination resulted safe and effective in inducing anti-CSPG4 immunity in OSA-affected dogs, which displayed prolonged survival as compared to controls. Finally, HuDo-CSPG4 was also able to induce a cytotoxic response in a human surrogate setting in vitro. On the basis of these results and the high predictive value of spontaneous OSA in dogs, this study paves the way for a possible translation of this approach to humans.

A meta-analysis: the clinical value of PD-1 inhibitor or protein tyrosine kinase inhibitors in the treatment of advanced osteosarcoma

Backgrounds

PD-1 inhibitors and TKIs have been used to treat advanced osteosarcoma, but there is still a lack of intuitive data for the comparison of their efficacy. We conducted a meta-analysis to evaluate their therapeutic benefits.

Methods

A systematic methodological search of five primary electronic databases was performed. Studies with a randomized design of any type about PD-1 inhibitors or TKIs for the treatment of advanced osteosarcoma were included. The primary outcomes mainly included CBR, PFS, OS and ORR, The CR, PR, SD and AEs were the secondary outcomes. The survival period (months) of patients was taken as the main analysis data. Random-effects models were used for meta-analysis.

Results

Eight immunocheckpoint inhibitors in 327 patients from 10 clinical trials were finally evaluated. For OS, TKIs [11.67 months (95% CI, 9.32-14.01)] show more obvious advantages than PD-1 inhibitors [6.37 months (95% CI, 3.96-8.78)]. For PFS, TKIs [4.79 months (95% CI, 3.33-6.24)] are longer than PD-1 inhibitors [1.46 months (95% CI, 1.23-1.69)]. Although there was no fatal event, attention should still be paid, especially during the combined application of PD-1 inhibitors with TKIs since their obvious AEs.

Conclusions

The findings of this study suggest that patients with advanced osteosarcoma, TKIs may be more beneficial than PD-1 inhibitors. TKIs combined with PD-1 inhibitors has a bright future in the treatment of advanced osteosarcoma, but we should always pay attention to the strong side effects.

Exosome-like Nanovesicles Derived from the Mucilage of Pinctada Martensii Exhibit Antitumor Activity against 143B Osteosarcoma Cells

Osteosarcoma is prone to metastasis and has a low long-term survival rate. The drug treatment of osteosarcoma, side effects of treatment drugs, and prognosis of patients with lung metastasis continue to present significant challenges, and the efficacy of drugs used in the treatment of osteosarcoma remains low. The development of new therapeutic drugs is urgently needed. In this study, we successfully isolated Pinctada martensii mucilage exosome-like nanovesicles (PMMENs). Our findings demonstrated that PMMENs inhibited the viability and proliferation of 143B cells, induced apoptosis, and inhibited cell proliferation by suppressing the activation of the ERK1/2 and Wnt signaling pathways. Furthermore, PMMENs inhibited cell migration and invasion by downregulating N-cadherin, vimentin, and matrix metalloprotease-2 protein expression levels. Transcriptomic and metabolomic analyses revealed that differential genes were co-enriched with differential metabolites in cancer signaling pathways. These results suggest that PMMENs may exert anti-tumor activity by targeting the ERK1/2 and Wnt signaling pathways. Moreover, tumor xenograft model experiments showed that PMMENs can inhibit the growth of osteosarcoma in mice. Thus, PMMENs may be a potential anti-osteosarcoma drug.

Tumor-associated macrophages induce inflammation and drug resistance in a mechanically tunable engineered model of osteosarcoma

The tumor microenvironment is a complex and dynamic ecosystem composed of various physical cues and biochemical signals that facilitate cancer progression, and tumor-associated macrophages are especially of interest as a treatable target due to their diverse pro-tumorigenic functions. Engineered three-dimensional models of tumors more effectively mimic the tumor microenvironment than monolayer cultures and can serve as a platform for investigating specific aspects of tumor biology within a controlled setting. To study the combinatorial effects of tumor-associated macrophages and microenvironment mechanical properties on osteosarcoma, we co-cultured human osteosarcoma cells with macrophages within biomaterials-based bone tumor niches with tunable stiffness. In the first 24 h of direct interaction between the two cell types, macrophages induced an inflammatory environment consisting of high concentrations of tumor necrosis factor alpha (TNFα) and interleukin (IL)-6 within moderately stiff scaffolds. Expression of Yes-associated protein (YAP), but not its homolog, transcriptional activator with PDZ-binding motif (TAZ), in osteosarcoma cells was significantly higher than in macrophages, and co-culture of the two cells slightly upregulated YAP in both cells, although not to a significant degree. Resistance to doxorubicin treatment in osteosarcoma cells was correlated with inflammation in the microenvironment, and signal transducer and activator of transcription 3 (STAT3) inhibition diminished the inflammation-related differences in drug resistance but ultimately did not improve the efficacy of doxorubicin. This work highlights that the biochemical cues conferred by tumor-associated macrophages in osteosarcoma are highly variable, and signals derived from the immune system should be considered in the development and testing of novel drugs for cancer.

Silencing circular RNA hsa_circABCC1 inhibits osteosarcoma progression through down-regulating HDAC4 via sponging miR-591

BACKGROUND

Circular RNA (circRNA) has been shown to play an important regulatory role in the development of various cancers, including osteosarcoma (OS). However, the role of circRNA ABCC1 (circABCC1) in OS was still poorly understood. The aim of our study was to investigate the role of circABCC1 in OS progression and its potential molecular mechanisms.

METHODS

The expression of circABCC1, microRNA-591 (miR-591) and histone deacetylase 4 (HDAC4) in OS tissues or cells was detected by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot (WB) analyses. In vitro experiments, the viability, proliferation, apoptosis, migration, invasion and autophagy of U2OS and HOS cells were assessed in vitro using cell counting kit-8 (CCK-8) assay, 5-ethynyl-29-deoxyuridine (EdU) assay, flow cytometry (FCM) assay, transwell migration and invasion assays (transwell) and WB assay, respectively. Interactions between circABCC1 and miR-591, miR-591 and HDAC4 were confirmed using a dual luciferase reporter gene assay system. The oncogenic role of circABCC1 in OS in vivo was examined by establishing a tumor xenograft model.

RESULTS

CircABCC1 was significantly elevated in OS tissues (about 3.1-folds) and cells (U2OS (about 2.1-folds) and HOS (about 2.8-folds)) compared with the control (p < .05). Silencing of circABCC1 significantly reduced the viability and proliferation, promoted apoptosis, impaired migration and invasion, and increased autophagy of U2OS and HOS cells (p < .05). In addition, miR-591 was confirmed to be a target of circABCC1, exerting an opposite effect to circABCC1 (p < .05). MiR-591 attenuation in U2OS and HOS cells was able to reply to the inhibition of cell proliferation, migration and invasion as well as promotion of cell apoptosis and autophagy mediated by silencing circABCC1 (p < .05). HDAC4 was verified to be the target gene of miR-591 in U2OS and HOS cells and was regulated by the circABCC1/miR-591 axis (p < .05), and restoration of HDAC4 levels in U2OS and HOS cells was able to restore the altered cellular function caused by silencing circABCC1 (p < .05). In addition, knockdown of circABCC1 attenuated tumor growth in vivo (p < .05).

CONCLUSION

Silencing of circABCC1 inhibits osteosarcoma progression by attenuating HDAC4 expression through sponging miR-591.

Regulation of the Epithelial to Mesenchymal Transition in Osteosarcoma

The epithelial to mesenchymal transition (EMT) is a cellular process that has been linked to the promotion of aggressive cellular features in many cancer types. It is characterized by the loss of the epithelial cell phenotype and a shift to a more mesenchymal phenotype and is accompanied by an associated change in cell markers. EMT is highly complex and regulated via multiple signaling pathways. While the importance of EMT is classically described for carcinomas-cancers of epithelial origin-it has also been clearly demonstrated in non-epithelial cancers, including osteosarcoma (OS), a primary bone cancer predominantly affecting children and young adults. Recent studies examining EMT in OS have highlighted regulatory roles for multiple proteins, non-coding nucleic acids, and components of the tumor micro-environment. This review serves to summarize these experimental findings, identify key families of regulatory molecules, and identify potential therapeutic targets specific to the EMT process in OS.

An Update on Circular RNA in Pediatric Cancers

Circular RNAs (circRNAs) are a class of single-stranded closed noncoding RNA molecules which are formed as a result of reverse splicing of mRNAs. Despite their relative abundance, only recently there appeared an increased interest in the understanding of their regulatory importance. Among their most relevant characteristics are high stability, abundance and evolutionary conservation among species. CircRNAs are implicated in several cellular functions, ranging from miRNA and protein sponges to transcriptional modulation and splicing. Additionally, circRNAs' aberrant expression in pathological conditions is bringing to light their possible use as diagnostic and prognostic biomarkers. Their use as indicator molecules of pathological changes is also supported by their peculiar covalent closed cyclic structure which bestows resistance to RNases. Their regulatory role in cancer pathogenesis and metastasis is supported by studies involving human tumors that have investigated different expression profiles of these molecules. As endogenous competitive RNA, circRNAs can regulate tumor proliferation and invasion and they arouse great consideration as potential therapeutic biomarkers and targets for cancer. In this review, we describe the most recent findings on circRNAs in the most common pediatric solid cancers (such as brain tumors, neuroblastomas, and sarcomas) and in more rare ones (such as Wilms tumors, hepatoblastomas, and retinoblastomas).

The clinical utility of dysregulated microRNA expression in paediatric solid tumours

MicroRNAs (miRNAs) are short, non-protein-coding genes that regulate the expression of numerous protein-coding genes. Their expression is dysregulated in cancer, where they may function as oncogenes or tumour suppressor genes. As miRNAs are highly resistant to degradation, they are ideal biomarker candidates to improve the diagnosis and clinical management of cancer, including prognostication. Furthermore, miRNAs dysregulated in malignancy represent potential therapeutic targets. The use of miRNAs for these purposes is a particularly attractive option to explore for paediatric malignancies, where the mutational burden is typically low, in contrast to cancers affecting adult patients. As childhood cancers are rare, it has taken time to accumulate the necessary body of evidence showing the potential for miRNAs to improve clinical management across this group of tumours. Here, we review the current literature regarding the potential clinical utility of miRNAs in paediatric solid tumours, which is now both timely and justified. Exploring such avenues is warranted to improve the management and outcomes of children affected by cancer.

The Combination of Anlotinib and Gemcitabine/Docetaxel in Patients with Metastatic Osteosarcoma Who Have Failed Standard Chemotherapy

Purpose

The options for the second-line treatment of metastatic osteosarcoma are still limited. Anlotinib is a multi-kinase inhibitor which has shown promising efficacy and good tolerability in various cancer types. This retrospective study was conducted to evaluate the efficacy and safety of anlotinib combined with gemcitabine/docetaxel (GD) in patients with metastatic osteosarcoma who have failed first-line chemotherapy.

Patients and Methods

The data of patients who received anlotinib combined with GD or GD were collected. The primary endpoint was progression-free survival. Secondary endpoints included objective response rate and safety.

Results

From July 2013 to November 2020, a total of 32 patients were enrolled, 13 received anlotinib combined with GD and 19 received GD. Median PFS was 9.0 months (95% CI 6.7-39.1) in the combination group and 5.0 months (95% CI 1.2-6.7) in the chemotherapy group. ORR were 38.4% and 15.8%, DCR were 69.2% and 38.1% in the combination and chemotherapy group, respectively. The most common adverse events included fatigue (78.9% in the combination group vs 69.2% in the chemotherapy group), hypertension (46.2% vs 10.5%), diarrhea (38.5% vs 21.1%), hypothyroidism (38.5% vs 15.8%), neutropenia (23.1% vs 36.8%) and AST elevation (30.8% vs 21.1%). The most common grade 3 or worse adverse events included hand-foot reaction (7.7% vs 5.3%), hypothyroidism (15.4% vs 0), neutropenia (0 vs 10.5%).

Conclusion

The combination of anlotinib and GD showed favorable efficacy with manageable toxicities compared with GD in the second-line treatment for metastatic osteosarcoma. This combination therapy deserves further investigations in patients with osteosarcoma.

Malignant bone tumors around the knee: A single-center experience

Aim: This study aimed to determine the frequency of malignant bone tumors (primary and metastatic) seen around the knee in our region, the patients’ type and demographic characteristics, and the treatments’ outcomes. Material and Method: A retrospective analysis of the patients who were diagnosed and treated with histopathologically malignant tumors in the knee region in our hospital between 2004-2021 was performed from the hospital database. Patients’ complaints, demographic information, and diagnostic and imaging findings were examined. In addition, tumor types, tumor localization, and treatments applied were analyzed. Results: Malignant bone tumor was detected in 88 (35.7%) of 246 patients included in the study. The patients were 48 women and 40 men, with a mean age of 39.72±21.8 (6-76 years). A total of 88 patients were divided into the pediatric group (&lt;18 years; n=39) and the adult group (≥18 years; n=49). The most common tumors were osteosarcoma in 54 (61.3%) and metastatic tumors in 22 (25%) patients. The most common localization of tumors was the distal femur with a rate of 75%. Metastasis was detected in 12 (18.2%) of 66 patients treated and followed up for primary malignant bone tumors. Limb sparing surgery was performed in 70 (79.5%), and various levels of amputation were performed in 14 (15.9%). Palliative radiotherapy was applied to two patients with metastatic lesions, while two patients who were in the neoadjuvant chemotherapy period died. The 5-year overall survival was 63.7%. Pediatric and adult age groups did not differ significantly in terms of survival (p=0.74), gender (p=0.585), and metastasis development (p=0.53). Conclusion: The knee is a region that requires attention regarding bone tumors around it. As malignant bone tumors are rarely seen around the knee, a misdiagnosis may be made, and appropriate treatment may be delayed. Although the first diagnosis to come to mind for patients presenting with knee pain is trauma and growing pains, it must not be forgotten that a tumor could be the cause.

Precision Medicine Highlights Dysregulation of the CDK4/6 Cell Cycle Regulatory Pathway in Pediatric, Adolescents and Young Adult Sarcomas

Simple Summary

This review provides an overview of clinical features and current therapies in children, adolescents, and young adults (AYA) with sarcoma. It highlights the basic and clinical findings on the cyclin-dependent kinases 4 and 6 (CDK4/6) cell cycle regulatory pathway in the context of the precision medicine-based molecular profiles of the three most common types of pediatric and AYA sarcomas—osteosarcoma (OS), rhabdomyosarcoma (RMS), and Ewing sarcoma (EWS).

Abstract

Despite improved therapeutic and clinical outcomes for patients with localized diseases, outcomes for pediatric and AYA sarcoma patients with high-grade or aggressive disease are still relatively poor. With advancements in next generation sequencing (NGS), precision medicine now provides a strategy to improve outcomes in patients with aggressive disease by identifying biomarkers of therapeutic sensitivity or resistance. The integration of NGS into clinical decision making not only increases the accuracy of diagnosis and prognosis, but also has the potential to identify effective and less toxic therapies for pediatric and AYA sarcomas. Genome and transcriptome profiling have detected dysregulation of the CDK4/6 cell cycle regulatory pathway in subpopulations of pediatric and AYA OS, RMS, and EWS. In these patients, the inhibition of CDK4/6 represents a promising precision medicine-guided therapy. There is a critical need, however, to identify novel and promising combination therapies to fight the development of resistance to CDK4/6 inhibition. In this review, we offer rationale and perspective on the promise and challenges of this therapeutic approach.

Long Noncoding RNA LINC00467: Role in Various Human Cancers

Intricate genetic mutations promote the progression of different cancer types. Long noncoding RNAs (lncRNAs) have been widely demonstrated to participate in the genomic activities of various human cancers. Long intergenic non-coding RNA 467 (LINC00467) is an upregulated lncRNA in diverse diseases, especially in several types of cancers. Functional experiments of LINC00467 revealed that LINC00467 overexpression enhanced cell chemoresistance, proliferation, migration, and invasion in several types of cancers. Moreover, overexpressed LINC00467 was associated with a poor clinical prognosis. The present evidence suggests that LINC00467 may serve as a promising prognostic indicator and become a novel cancer therapeutic target. In this review, we introduce the biologic functions of lncRNAs and describe the molecular mechanism and clinical significance of LINC00467 in detail.

Osteosarcoma-Specific Genes as a Diagnostic Tool and Clinical Predictor of Tumor Progression

Simple Summary

The standard method for the diagnosis and monitoring of osteosarcoma is biopsy and tumor imaging, which causes discomfort to patients and is difficult to repeat. A blood sample can be used as a non-invasive method for monitoring tumor material. Vimentin and ezrin show clinical significance in samples obtained from OS patients but need circulating tumor cell purification, since they are expressed in leukocytes. Due to the low-temperature storage of the samples, it proved impossible to perform purification to remove the contamination. We propose that novel or OS-specific biomarkers using differential gene expression from the Gene Expression Omnibus (GEO) database is a promising approach for developing diagnostic and tumor progression strategies. Seven genes from the database showed significant expression in OS cell lines/primary cells compared to a normal blood donor, together with ezrin and VIM. The expression of the five candidate genes together with ezrin and vimentin were quantified by qRT-PCR and analyzed using a mathematical model with high efficiency to discriminate between OS patients and normal samples, resulting in the selection of three candidate genes: COL5A2 (one of the five from the database) as well as ezrin and VIM. Our study demonstrates that these genes in retrospective samples could serve as tools of OS detection and predictors of disease progression.

Abstract

A liquid biopsy is currently an interesting tool for measuring tumor material with the advantage of being non-invasive. The overexpression of vimentin and ezrin genes was associated with epithelial-mesenchymal transition (EMT), a key process in metastasis and progression in osteosarcoma (OS). In this study, we identified other OS-specific genes by calculating differential gene expression using the Gene Expression Omnibus (GEO) database, confirmed by using quantitative reverse transcription-PCR (qRT-PCR) to detect OS-specific genes, including VIM and ezrin in the buffy coat, which were obtained from the whole blood of OS patients and healthy donors. Furthermore, the diagnostic model for OS detection was generated by utilizing binary logistic regression with a multivariable fractional polynomial (MFP) algorithm. The model incorporating VIM, ezrin, and COL5A2 genes exhibited outstanding discriminative ability, as determined by the receiver operating characteristic curve (AUC = 0.9805, 95% CI 0.9603, 1.000). At the probability cut-off value of 0.3366, the sensitivity and the specificity of the model for detecting OS were 98.63% (95% CI 90.5, 99.7) and 94.94% (95% CI 87.5, 98.6), respectively. Bioinformatic analysis and qRT-PCR, in our study, identified three candidate genes that are potential diagnostic and prognostic genes for OS.

Discovery of 2-Amino-3-cyanothiophene Derivatives as Potent STAT3 Inhibitors for the Treatment of Osteosarcoma Growth and Metastasis

Osteosarcoma is one of the most common malignant bone tumors. However, the treatment and clinical outcomes of osteosarcoma have hardly changed over the past three decades due to the comprehensive heterogeneity and higher rate of mutation of osteosarcoma. Recent studies have shown that STAT3 has the potential to suppress the proliferation and metastasis of osteosarcoma. In this study, a novel class of 2-amino-3-cyanothiophene derivatives were designed and synthesized to inhibit osteosarcoma by targeting STAT3. Representative compound 6f showed potent antiproliferative effects against osteosarcoma cells, directly bound to the STAT3 SH2 domain with a K_D of 0.46 μM, and inhibited the phosphorylation of STAT3 Y705 in a dose-dependent manner. Furthermore, compound 6f promoted osteosarcoma cell apoptosis in vitro and significantly suppressed the growth and metastasis of osteosarcoma in vivo. These findings demonstrate that targeting STAT3 may be a feasible therapeutic strategy for the treatment of metastatic osteosarcoma.

Risk and Prognostic Factors for Different Organ Metastasis in Primary Osteosarcoma: A Large Population-Based Analysis

OBJECTIVE

Based on a large public cohort, we aimed to investigate the prevalence of distant metastases in patients with osteosarcoma, to evaluate the survival of patients with different metastases and to reveal the related risk and prognostic factors for distant metastases.

METHODS

The information of osteosarcoma patients with or without distant metastases was retrospectively extracted from the Surveillance, Epidemiology, and End Result database from January 2010 to December 2015. Patients were excluded if they were diagnosed at autopsy or via death certification. The Kaplan-Meier method was used to calculate the overall survival in the entire cohort and across patients with metastases to different organs. The related prognostic factors were investigated by univariate and multivariate Cox proportional hazard regression analysis. The logistic regression method was used to reveal the risk factors for the development of different metastases. The effects of different variables on the survival and prevalence of distant metastases were compared using subgroup analysis. Variables with P < 0.05 in the univariate regression analysis were further examined using multivariate regression analysis.

RESULTS

In total, 1470 osteosarcoma patients (mean age 30 ± 22 years) were included, among which 278 patients (18.9%) were initially diagnosed with distant metastasis. The median follow-up duration was 33.0 (30.2-35.8) months. The lung was the most common metastatic site (83.8%), followed by the bone (21.9%), liver (2.9%), and brain (2.2%). A total of 232 patients (83.5%) presented only one distant metastatic site, while the other 46 patients showed two or more metastatic sites. A lower proportion of metastasis was observed in patients aged from 25 to 59 years [odds ratio (OR) = 0.59; 95% confidence interval (CI): 0.37-0.95]. More metastases were noted in patients with T2/T1 (OR = 1.91; 95% CI: 1.28-2.84), T3/T1 (OR = 4.48; 95% CI: 1.78-11.30) and N1/N0 stages (OR = 6.66; 95% CI: 2.68-16.56). The 1-, 3-, and 5-year overall survival rates for metastatic patients were 57.3% (95% CI: 50.8%-63.8%), 25.3% (95% CI: 18.8%-31.9%), and 18.1% (95% CI: 10.2%-26.0%), respectively. Metastatic patients older than 25 years were prone to have poor survival and a relatively better prognosis (hazard ratio = 0.41; 95% CI: 0.25-0.69) was noticed among those who underwent surgery on the primary site. Different metastatic organs have homogeneous and heterogeneous risk and prognostic factors.

CONCLUSION

The high incidence of initial distant metastasis in osteosarcoma and the inconsistent predictive factors should be given more attention in the clinical management of patients with osteosarcoma.

Recent and Ongoing Research into Metastatic Osteosarcoma Treatments

The survival rate for metastatic osteosarcoma has not improved for several decades, since the introduction and refinement of chemotherapy as a treatment in addition to surgery. Over two thirds of metastatic osteosarcoma patients, many of whom are children or adolescents, fail to exhibit durable responses and succumb to their disease. Concerted efforts have been made to increase survival rates through identification of candidate therapies via animal studies and early phase trials of novel treatments, but unfortunately, this work has produced negligible improvements to the survival rate for metastatic osteosarcoma patients. This review summarizes data from clinical trials of metastatic osteosarcoma therapies as well as pre-clinical studies that report efficacy of novel drugs against metastatic osteosarcoma in vivo. Considerations regarding the design of animal studies and clinical trials to improve survival outcomes for metastatic osteosarcoma patients are also discussed.

Non-Private Health Insurance Predicts Advanced Stage at Presentation and Amputation in Lower Extremity High Grade Bone Sarcoma: A National Cancer Database Study : Amputation Predicts Survival: An Effect Most Pronounced in Pediatric and AYA Age Group

INTRODUCTION

Advances in diagnostic and treatment modalities for high grade bone sarcomas (HGBS) of lower extremity (LE) have enabled limb salvage resections as a feasible first-line surgical option. However, amputations are still performed. Impact of amputation on survival and predictive factors for amputation and the stage at presentation for HGBS of LE remain unknown.

METHODS

National Cancer Database was used to extract 5781 cases of high-grade bone sarcoma of the LE from 2004 to 2017. Kaplan-Meier and Cox regression were used to determine the impact of amputation on survival. Chi square test and logistic regression were used to assess the correlation of predictive factors with amputation and stage at presentation.

RESULTS

Amputation [hazard ratio (HR) 1.516; 95% confidence interval (CI) 1.259-1.826; p < 0.001] and advanced stage (HR 0.248; 95% CI 0.176-0.351; p < 0.001) were independent predictors of poor overall survival. The impact of amputation on survival was most pronounced for pediatric and adolescents and young adults (AYA) age groups (18% decrease in 10-year survival). Amputation was more likely to be performed among those with nonprivate insurance (HR 1.736; 95% CI 1.191-2.531; p = 0.004), a finding that was mirrored for advanced stage at presentation (HR 0.611; 95% CI 0.414-0.902; p = 0.013).

DISCUSSION

Amputation is an independent predictor of poor outcomes among patients with HGBS of LE. The impact of amputation on survival is the highest for the pediatric and AYA age group. Nonprivate insurance is associated with increased likelihood of amputation and an advanced stage at presentation among patients with high-grade bone sarcoma of the LE. This is the largest study highlighting insurance-related disparities in this cohort.

Circle RNA circCSPP1 promotes human osteosarcoma cell proliferation and increases glucose metabolism by suppressing miR-200c maturation

INTRODUCTION

MiR-200c plays a central role in glucose metabolism in cancer cells. However, its upstream regulators in this process are unknown. CircRNA CSPP1 (circCSPP1) was predicted to bind to premature miR-200c, an oncogenic miRNA. Therefore, we explored their interaction in osteosarcoma (OS).

METHODS

Differential circCSPP1 and miR-200c expression in OS was analyzed using RT-qPCR. Glucose metabolism was analyzed by glucose uptake assay. Subcellular circCSPP1 location in OS cells was detected using cellular fractionation assay. The direct interaction between circCSPP1 and miR-200c was explored using RNA-RNA pull-down assay. The role of circCSPP1 in miR-200c maturation was investigated by analyzing both mature and premature miR-200c levels in OS cells with circCSPP1 overexpression.

RESULTS

CircCSPP1 and premature miR-200c levels were increased while mature miR-200c level was decreased in OS. CircCSPP1 was detected in both the nuclear and cytoplasm fractions of OS cells. CircCSPP1 directly interacted with premature miR-200c. CircCSPP1 overexpression increased premature miR-200c level, glucose uptake, and cell proliferation, but decreased mature miR-200c level. MiR-200c overexpression suppressed the role of circCSPP1 in OS cells.

CONCLUSIONS

CircCSPP1 promotes OS cell proliferation and increases glucose metabolism by suppressing miR-200c maturation.

Skip metastases in high-grade intramedullary appendicular osteosarcoma: an indicator of more aggressive disease?

OBJECTIVE

To determine whether skip metastases (SM) in high-grade appendicular osteosarcoma (HG-OS) are an indicator of more aggressive disease.

MATERIALS AND METHOD

Retrospective review of patients with histologically confirmed diagnosis HG-OS of the long bones from 2007 to 2020, who had whole-bone MRI to identify SM. Data collected included patient age/gender, bone involved, the presence of SM, the presence of lung metastases from chest CT, the presence of distant bone metastases from whole-body bone scintigraphy or whole-body MRI, and chemotherapy response from resection specimen histology. The presence of lung or bone metastases and chemotherapy response were compared between patients without and with SM.

RESULTS

The study included 241 patients (146 males; 95 females: mean age 18.2 years; range 4-73 years). Based on whole-bone MRI, 202 (83.8%) patients had no SM and 39 (16.2%) patients had a SM. Of patients without a SM, lung metastases were identified in 44 (22%) and distant bone metastases in 6 (3%) cases, while 80 (43%) had a good chemotherapy response and 105 (57%) had a poor chemotherapy response. Of patients with a SM, lung metastases were identified in 22 (58%) and distant bone metastases in 8 (21%) cases, while 11 (32%) had a good chemotherapy response and 23 (68%) had a poor chemotherapy response. The presence of SM was significantly associated with both lung metastases (p < 0.001) and skeletal metastases (p < 0.001), but not with chemotherapy response (p = 0.24). Patients with SM also had poorer survival (p < 0.001).

CONCLUSIONS

The presence of SM in appendicular HG-OS suggests more aggressive disease.

Large Scale Identification of Osteosarcoma Pathogenic Genes by Multiple Extreme Learning Machine

At present, the main treatment methods of osteosarcoma are chemotherapy and surgery. Its 5-year survival rate has not been significantly improved in the past decades. Osteosarcoma has extremely complex multigenomic heterogeneity and lacks universally applicable signal blocking targets. Osteosarcoma is often found in adolescents or children under the age of 20, so it is very important to explore its genetic pathogenic factors. We used known osteosarcoma-related genes and computer algorithms to find more osteosarcoma pathogenic genes, laying the foundation for the treatment of osteosarcoma immune microenvironment-related treatments, so as to carry out further explorations on these genes. It is a traditional method to identify osteosarcoma related genes by collecting clinical samples, measuring gene expressions by RNA-seq technology and comparing differentially expressed gene. The high cost and time consumption make it difficult to carry out research on a large scale. In this paper, we developed a novel method “RELM” which fuses multiple extreme learning machines (ELM) to identify osteosarcoma pathogenic genes. The AUC and AUPR of RELM are 0.91 and 0.88, respectively, in 10-cross validation, which illustrates the reliability of RELM.

LncRNA KASRT Serves as a Potential Treatment Target by Regulating SRSF1-Related KLF6 Alternative Splicing and the P21/CCND1 Pathway in Osteosarcoma: An In Vitro and In Vivo Study

Purpose

Long non-coding RNA KLF6 alternative splicing regulating transcript (lnc-KASRT) locates within the intronic region of SRSF1, possessing the potential to regulate KLF6 alternative splicing to promote carcinogenicity. Then, the current in vitro and in vivo study aimed to investigate the effect of lnc-KASRT on regulating tumor malignant behaviors, and the implication of its interaction with KLF6 alternative splicing in osteosarcoma.

Methods

Lnc-KASRT overexpression or knockdown plasmid was transfected into U-2OS and Saos-2 cells. Then, KLF6-SV1 knockdown plasmid with or without lnc-KASRT overexpression plasmid was transfected into these cells for compensative experiments. In vivo, lnc-KASRT overexpression or knockdown Saos-2 cells were injected in mice for tumor xenograft construction.

Results

Lnc-KASRT expression was increased in most osteosarcoma cell lines compared to control cell line. Lnc-KASRT overexpression promoted cell viability, mobility, and anti-apoptotic marker expression, while reducing apoptosis rate and pro-apoptotic marker expression; meanwhile, it regulated SRSF1, KLF6 alternative splicing (increased KLF6-splice variant 1 (KLF6-SV1), decreased KLF6-wild type (KLF6-WT)), and followed P21/CCND1 pathway in U-2OS/Saos-2 cells. The lnc-KASRT knockdown exhibited opposite trends. Subsequent compensative experiments disclosed that KLF6-SV1 knockdown attenuated most of the tumor-promoting effects of lnc-KASRT overexpression in U-2OS/Saos-2 cells. In vivo experiments further validated that lnc-KASRT enhanced tumor growth and reduced tumor apoptosis; meanwhile, it also increased tumor KLF6-SV1, MMP-1, and MMP-9 expressions but decreased tumor SRSF1 and KLF6-WT expressions in xenograft mice.

Conclusion

Lnc-KASRT serves as a potential treatment target via regulating SRSF1-related KLF6 alternative splicing and following P21/CCND1 pathway in osteosarcoma.

miR-877 inhibits the proliferation, migration, and invasion of osteosarcoma cells by targeting gamma-glutamylcyclotransferase

Gamma-glutamylcyclotransferase (GGCT) can promote the progression of osteosarcoma (OS). MicroRNAs also play significant roles in regulating the progression of OS. This study was designed to investigate whether miR-877 exerts its function in OS by targeting GGCT. The proliferation of OS cells (Saos-2 and U2OS) was detected by MTT and colony formation assays. The migration and invasion of OS cells were detected by transwell assays. The expressions of miRNAs and GGCT were detected by quantitative real-time PCR and Western blot. The luciferase reporter assay was performed to assess whether miR-877 could target GGCT. miR-877 was down-regulated both in OS tissues and OS cell lines (Saos-2 and U2OS). The overexpression of miR-877 inhibited the proliferation, migration, and invasion of OS cell lines, while the knockdown of miR-877 could negate effects. The expression of GGCT was increased in Saos-2 and U2OS cells. miR-877 could target GGCT, and the mRNA level of GGCT in Saos-2 and U2OS cells was decreased by the overexpression of miR-877. miR-877 overexpression inhibited the migration and invasion and suppressed the proliferation of Saos-2 and U2OS cells, and the overexpression of GGCT reversed this effects. The knockdown of miR-877 promoted the migration and invasion and facilitated the proliferation of Saos-2 and U2OS cells, and the silence of GGCT abolished this effects. Our findings suggested that miR-877 could inhibit the proliferation, migration, and invasion of OS cells by targeting GGCT.

Targeting the VEGF Pathway in Osteosarcoma

Osteosarcoma is the most common primary tumor of the bones affecting mainly young adults. Despite the advances in the field of systemic anticancer therapy, the prognosis of relapsed of metastatic osteosarcoma patients remain dismal with very short survival. However, the better understanding of the pathophysiology of this subtype of sarcoma has led to the identification of new targeted agents with significant activity. In fact, increased angiogenesis plays a major role in the tumor growth and survival of osteosarcoma patients. Several targeted agents have demonstrated a significant anti-tumor activity including multi-kinase inhibitors. In this review, we will discuss the pathophysiology, rationale, and role of targeting angiogenesis via the VEGF pathway in patients with osteosarcoma with emphasis on the published clinical trials and future directions.

Interleukin-4 Receptor Inhibition Targeting Metastasis Independent of Macrophages

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma occurring in children and carries a dismal prognosis when metastatic disease is detected. Our previous work has suggested the cytokine receptor IL4Rα may play a role in contributing to metastasis in the alveolar subtype of rhabdomyosarcoma (aRMS), and thus could present a therapeutic target. The IL4 signaling axis has been characterized in various adult cancers as well; however, pediatric trials often follow similar adult trials and the role of the IL4Rα receptor has not been explored in the context of a mediator of metastasis in adult disease. Here, we demonstrate that the impact of IL4Rα blockade in an orthotopic allograft model of aRMS is not mediated by a macrophage response. We further examine the effect of IL4 blockade in adult colon, breast, and prostate cancers and find that inhibition of IL4Rα signaling modulates in vitro cell viability of HCT-116 colon carcinoma cells; however, this finding did not translate to an autocrine-related in vivo difference in tumor burden or lung metastasis. Our results suggest that if humanized IL4 mouse host strains are not available (or not ideal due to the need for immunosuppressing the host innate immune response for xenograft systems), then genetically-engineered mice and mouse allograft studies may be the best indicator of therapeutic targeting efficacy.

Staging and Classification of Primary Musculoskeletal Bone and Soft Tissue Tumors Based on the 2020 WHO Update, From the AJR Special Series on Cancer Staging

Staging of primary musculoskeletal bone and soft tissue tumors is most commonly performed using the AJCC and the Enneking or Musculoskeletal Tumor Society (MSTS) staging systems. Radiologic imaging is integral in achieving adequate musculoskeletal neoplastic staging by defining lesion extent and identifying regional lymph node involvement and distant metastatic disease. Additional important features in surgical planning, though not distinct components of the staging systems, include cortical involvement, joint invasion, and neurovascular encasement; these features are optimally evaluated by MRI. In 2020, the WHO updated the classification of primary musculoskeletal tumors of soft tissue and bone. The update reflects the continued explosion in identification of novel gene alterations in many bone and soft tissue neoplasms. This has resulted in newly designated lesions, reclassification of lesion categories, and improved specificity of diagnosis. While radiologists do not need to have a comprehensive knowledge of the pathologic details, a broad working understanding of the most recent update is important to aid accurate and timely diagnosis given that histologic grading is a component of all staging systems. By approaching primary musculoskeletal neoplasms through a multidisciplinary approach with colleagues in pathology, orthopedic oncology, radiation oncology, and medical oncology, radiologists may promote improved diagnosis, treatment, and outcomes.

The regulatory effect of has-circ-0001146/miR-26a-5p/MNAT1 network on the proliferation and invasion of osteosarcoma

Osteosarcoma is a malignant bone tumour with the lowest survival rates out of all paediatric cancers and is primarily diagnosed in children and adolescents. MNAT1 is a subunit in the cyclin-dependent kinase-activating kinase complex. Abnormal up-regulation of MNAT1 has been associated with the poor prognosis of multiple cancers. Bioinformatics analysis showed that has-circ-0001146 and miR-26a-5p were involved in the regulation of MNAT1 in osteosarcoma. The present study investigated the regulatory effects of has-circ-0001146 and miR-26a-5p on MNAT1 expression using luciferase reporter and RNA-pull down assays. The effects of the has-circ-0001146/miR26a-5p/Mnat1 network on the proliferation and invasion of osteosarcoma were evaluated by cell viability, apoptosis, migration, and invasion assays. Osteosarcoma tissues showed higher MNAT1 and has-circ-0001146 expression than adjacent normal tissues, although the expression of MNAT1 was not significantly up-regulated in sarcomas according to TCGA databases. As indicated by luciferase reporter and RNA-pull down assays, miR-26a-5p was able to bind to both has-circ-0001146 and MNAT1 mRNA. The depletion of has-circ-0001146 as well as the increase of miR-26a-5p decreased MNAT1 expression in osteosarcoma cells, while the reduction of miR-26a-5p was associated with increased MNAT1 expression. These data suggested that has-circ-0001146 promoted MNAT1 expression by competitively binding to miR-26a-5p with MNAT1 mRNA. The depletion of has-circ-0001146 or MNAT1 or the increase of miR-26a-5p inhibited osteosarcoma cell viability and invasion, and increased apoptosis. Reduction of miR-26a-5p conversely promoted osteosarcoma cell viability and invasion. The present study confirmed that has-circ-0001146 blocked miR-26a-5p targeting MNAT1 in osteosarcoma cells, thereby promoting the malignant behaviours of osteosarcoma cells.

The relationship between the expression of Ki-67 and the prognosis of osteosarcoma

Background

A number of studies have linked positive Ki-67 expression with the prognosis of osteosarcoma (OS) patients. However, the results have been conflicting. To address this controversy, we conducted an analysis using a meta-analysis and a TCGA dataset to estimate the value of Ki-67 expression in the prognosis of OS.

Methods

A comprehensive search for relevant papers was conducted using NCBI PubMed, Embase, Springer, ISI Web of Knowledge, the Cochrane Library, and CNKI regardless of the publication year. The associations between Ki-67 expression and the clinical features and main prognostic outcomes of OS were measured. The TCGA dataset was also analyzed. The pooled odds ratio (OR) and its 95% confidential intervals (CIs) were utilized for statistical analysis.

Results

Overall, a total of 12 studies with 500 cases were included, and the results indicated that the expression of Ki-67 was significantly associated with Enneking stage (OR = 6.88, 95% CI: 2.92–16.22, p < 0.05), distant metastasis (OR = 3.04, 95% CI: 1.51–6.12, p < 0.05) and overall survival (OR = 8.82, 95% CI: 4.68–16.65, p < 0.05) in OS patients. Additionally, we observed no significant heterogeneity among all retrieved studies. Associations between Ki-67 expression and overall survival and disease-free survival of sarcoma were confirmed using the TCGA and Kaplan-Meier plotter datasets.

Conclusion

The present study strongly suggests that positive Ki-67 expression was associated with Enneking stage, distant metastasis, and overall survival of OS, and it may be used as a potential biomarker to predict prognosis and guide clinical therapy for OS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-07880-y.

The lncRNA NEAT1 promotes the epithelial-mesenchymal transition and metastasis of osteosarcoma cells by sponging miR-483 to upregulate STAT3 expression

Background

Osteosarcoma is one of the most prevalent primary bone tumours in adolescents. Accumulating evidence shows that aberrant expression of the long non-coding RNA (lncRNA) NEAT1 and microRNA-483 (miR-483) contribute to the epithelial-mesenchymal transition (EMT), invasion and metastasis of tumour cells. However, the potential regulatory effects of NEAT1 and miR-483 on the EMT of osteosarcoma remain elusive.

Methods

The expression of the NEAT1, miR-483, signal transducer and activator of transcription-1 (STAT1), STAT3, and EMT-associated markers was measured using qRT-PCR or western blotting. NEAT1 overexpression or knockdown was induced by lentivirus-mediated transfection. A luciferase reporter assay was employed to confirm the association between NEAT1/miR-483 and miR-483/STAT3. RNA immunoprecipitation (RIP) was also performed to verify the NEAT1 and miR-483 interaction. Wound healing and transwell assays were implemented to assess the migration and invasion of U2OS cells. Unilateral subcutaneous injection of U2OS into nude mice was performed to investigate tumour metastasis in vivo.

Results

The expression of miR-483 was downregulated in both osteosarcoma cell lines and osteosarcoma tissues. The overexpression of miR-483 suppressed the migration, invasion, and expression of EMT-associated proteins in U2OS cells, while simultaneous overexpression of STAT3 partially relieved this suppression. Mechanistically, miR-483 specifically targeted the 3′ untranslated region (3′UTR) of STAT3 and repressed its expression. However, NEAT1 sponged miR-438, increased STAT3 expression, and repressed STAT1 expression, subsequently increasing the EMT of osteosarcoma cells. The knockdown of NEAT1 in transplanted U2OS cells impaired the liver and lung metastases of osteosarcoma in nude mice. Moreover, NEAT1 silencing inhibited the mesenchymal- epithelial transition (MET) of osteosarcoma at metastasis sites.

Conclusions

The lncRNA NEAT1/miR-483/STAT3 axis plays a crucial role in regulating the metastasis of osteosarcoma and potentially represents one appealing therapeutic target for osteosarcoma treatment in the future.

High expression of ABCG2 is associated with chemotherapy resistance of osteosarcoma

Objectives

Previous studies showed overexpression of ABCG2 in a variety of tumor tissues, which could potentially indicate the probability of chemotherapy resistance. This study aimed to reveal the role of ABCG2 in the development of chemotherapy resistance and the prognosis of osteosarcoma (OS).

Methods

Sixty-eight OS patients were included in this study. Tumor tissues were collected for each patient during surgery. DOX-resistant OS cell lines were induced by consecutive exposure of gradually increasing concentration of DOX to the parental cell lines. Lentivirus was used for the knockdown of ABCG2 in OS cells. Cells were treated with the gradient concentration of DOX, and the viability was assessed by CCK8 assay. Total RNA was isolated from the tumor tissues or tumor cells, and the expression of ABCG2 was analyzed by qPCR. The relationship between ABCG2 expression and clinicopathological characteristics of the patients was analyzed using Student’s t test or the Chi-square test. The overall survival time was calculated by the Kaplan-Meier method and analyzed by the log-rank test. p < 0.05 was considered statistically significant.

Results

DOX-resistant OS cells were successfully established through continuous exposure to DOX. Forty-eight hours after DOX exposure, the IC 50 value of DOX-resistant HOS cells and DOX-resistant U2OS was 3.5 μM and 3.25 μM, respectively. By contrast, those of the untreated HOS and U2OS cells were 1.15 μM and 0.93 μM, respectively (p < 0.01). The mRNA expression level of ABCG2 was significantly increased in DOX-resistant cell lines. The CCK-8 assay showed that the DOX-resistant HOS cells and DOX-resistant U2OS cells transfected with ShABCG2 were more sensitive to the DOX treatment than those transfected with ShCtrl. Analysis of gene expression in OS tissues showed remarkably higher expression of ABCG2 as compared with adjacent normal tissues (p < 0.01). Patients with high expression level of ABCG2 had obviously decreased overall survival time than the patients with normal expression (p < 0.01).

Conclusions

ABCG2 expression level was significantly associated with the resistance to chemotherapy and the overall survival of OS patients. ABCG2 may be a promising therapeutic target for OS patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02204-z.

Neurophysiological Mechanisms Related to Pain Management in Bone Tumors

BACKGROUND

Primary and metastatic bone tumor incidence has increased in the previous years. Pain is a common symptom and is one of the most important related factors to the decrease of quality of life in patients with bone tumor. Different pain management strategies are not completely effective and many patients afflicted by cancer pain cannot be controlled properly. In this sense, we need to elucidate the neurophysiology of cancer-induced pain, contemplating other components such as inflammation, neuropathies and cognitive components regarding bone tumors, and thus pave the way for novel therapeutic approaches in this field.

AIM

This study aims to identify the neurophysiology of the mechanisms related to pain management in bone tumors.

METHODS

Advanced searches were performed in scientific databases: PubMed, ProQuest, EBSCO, and the Science Citation index to get information about the neurophysiology mechanisms related to pain management in bone tumors.

RESULTS

The central and peripheral mechanisms that promote bone cancer pain are poorly understood. Studies have shown that bone cancer could be related to neurochemicals produced by tumor and inflammatory cells, coupled with peripheral sensitization due to nerve compression and injury caused by tumor growth. The activity of mesolimbic dopaminergic neurons, substance P, cysteine/ glutamate antiporter, and other neurochemical dynamics brings us putative strategies to suggest better and efficient treatments against pain in cancer patients.

CONCLUSION

Cancer-induced bone pain could include neuropathic and inflammatory pain, but with different modifications to the periphery tissue, nerves and neurochemical changes in different neurological levels. In this sense, we explore opportunity areas in pharmacological and nonpharmacological pain management, according to pain-involved mechanisms in this study.

A Multi-Objective Approach for Anti-Osteosarcoma Cancer Agents Discovery through Drug Repurposing

Osteosarcoma is the most common type of primary malignant bone tumor. Although nowadays 5-year survival rates can reach up to 60–70%, acute complications and late effects of osteosarcoma therapy are two of the limiting factors in treatments. We developed a multi-objective algorithm for the repurposing of new anti-osteosarcoma drugs, based on the modeling of molecules with described activity for HOS, MG63, SAOS2, and U2OS cell lines in the ChEMBL database. Several predictive models were obtained for each cell line and those with accuracy greater than 0.8 were integrated into a desirability function for the final multi-objective model. An exhaustive exploration of model combinations was carried out to obtain the best multi-objective model in virtual screening. For the top 1% of the screened list, the final model showed a BEDROC = 0.562, EF = 27.6, and AUC = 0.653. The repositioning was performed on 2218 molecules described in DrugBank. Within the top-ranked drugs, we found: temsirolimus, paclitaxel, sirolimus, everolimus, and cabazitaxel, which are antineoplastic drugs described in clinical trials for cancer in general. Interestingly, we found several broad-spectrum antibiotics and antiretroviral agents. This powerful model predicts several drugs that should be studied in depth to find new chemotherapy regimens and to propose new strategies for osteosarcoma treatment.

MiR-1224-5p Activates Autophagy, Cell Invasion and Inhibits Epithelial-to-Mesenchymal Transition in Osteosarcoma Cells by Directly Targeting PLK1 Through PI3K/AKT/mTOR Signaling Pathway

Background

Osteosarcoma (OS) is one of the most common malignant bone tumors with a poor overall prognosis. MiR-1224-5p plays an important role in cancer, but its function and mechanism in OS have not been studied.

Materials and Methods

The expression of miR-1224-5p and PLK1 was detected by qRT-PCR in OS cells, adjacent tissues, and cell lines. Dual-luciferase reporter gene assay was used to verify the interaction between miR-1224-5p and PLK1. The expression of miR-1224-5p and PLK1 was intervened by transfection with miR-1224-5p mimic, NC mimic, pc-NC and PLK1, respectively. MTT, colony formation assay, Transwell and flow cytometry were used to observe the cell proliferation, invasion and apoptosis. Western blot was used to detect the expression levels of PLK1, PI3K/AKT/mTOR signaling pathway-related proteins, autophagy-related proteins, and epithelial-mesenchymal transition (EMT)-related proteins in the cells.

Results

We found that miR-1224-5p was down-regulated and PLK1 expression was up-regulated in OS tissues and cells. On the other hand, it is further confirmed that PLK1 was a target gene of miR-1224-5p. Overexpression of miR-1224-5p inhibited the proliferation, invasion while promoted the apoptosis of OS cells, whereas overexpression of PLK1 promoted the proliferation, invasion and inhibited the apoptosis of OS cells. In the miR-1224-5p group (overexpression of miR-1224-5p), PI3K, AKT, and mTOR protein phosphorylation levels were significantly reduced, while autophagic activity was significantly activated, and the degree of EMT was significantly reduced. But the results in the PLK1 group (overexpression of PLK1) were the opposite. In addition, overexpression of miR-1224-5p reversed the effect of PLK1 upregulation on OS cells.

Conclusion

MiR-1224-5p targets PLK1 to inhibit PI3K/AKT/mTOR signaling pathway, thus mediating the proliferation, invasion, apoptosis, autophagy and EMT in OS cells.

Popliteal lymph nodes in patients with osteosarcoma: are they metastatic?

PURPOSE

To evaluate the prevalence, imaging appearance, and significance of popliteal lymph nodes (PLN) on magnetic resonance imaging (MRI) in patients with distal femoral or proximal tibial osteosarcoma (OS).

METHOD AND MATERIALS

This study included consecutive patients with OS presenting from May 2016 to March 2018. Inclusion criteria were patients with distal femoral or proximal tibial OS with MRI and pathology at our institution. On MRI, two radiologists recorded primary tumor features (size, location, signal, extra-compartmental extension), and PLN characteristics (mean size, presence/absence of fatty hilum, mineralization, PET/bone scintigraphy avidity, contrast enhancement, and diffusion restriction). Tumor histology, stage, and clinical follow-up were recorded. Descriptive statistics were provided.

RESULTS

Sixteen patients with OS (age 20 ± 10 (range10-40) years, 10/16 male) were included. Although 81% (13/16) of the patients had PLNs at presentation (size range 0.3-3.6 cm), fewer patients had extra-compartmental spread: intra-articular extension 50% (8/16), skip lesions 19% (3/16), lung metastases 31% (5/16), and osseous metastases 12% (2/16). Four (25% (4/16)) patients had PLN ≥ 1 cm; two were histologically proven reactive. One was presumed metastatic due to rapid development, mineralization, and FDG-avidity on PET/CT. The other ≥ 1 cm PLNs along with all twelve (75% (12/16)) that were < 1 cm in mean diameter were presumed non-metastatic with documented stability for at least 12 months of follow-up.

CONCLUSION

PLNs are frequently visible on MRI in patients with OS but are rarely (prevalence = 6%) metastatic. Features on MRI which may suggest metastatic PLNs include large size > 1 cm and loss of a fatty hilum.

Current Treatment Considerations for Osteosarcoma Metastatic at Presentation

Approximately one-fourth of osteosarcoma patients have metastases at presentation. The best treatment options for these patients include chemotherapy, surgery, and radiotherapy; however, the optimal scheme has not yet been defined. Standard chemotherapy for osteosarcoma metastatic at presentation is based on high-dose methotrexate, doxorubicin, and cisplatin (the MAP regimen), with the possible addition of ifosfamide. Surgical treatment continues to be fundamental; complete surgical resection of all sites of disease (primary and metastatic) remains essential for survival. In patients whose tumors do not respond to neoadjuvant chemotherapy, early surgical resection of the primary tumor with limb-salvage surgery or amputation and multiple metastasectomies, if feasible, after the completion of adjuvant chemotherapy is a reasonable option, as the reduction of the tumor volume could probably increase the effect of chemotherapy. Advanced radiotherapy techniques, such as carbon ion radiotherapy and stereotactic radiosurgery, and molecular targeted chemo-therapy with drugs such as pazopanib or apatinib have improved the dismal prognosis, especially for patients who are medically inoperable or who refuse surgery. Given that the presence of metastatic disease at diagnosis of a patient with osteosarcoma is a poor prognostic factor, a multidisciplinary approach by surgeons, medical oncologists, and radiotherapists is important. [Orthopedics. 2020;43(5):e345-e358.].

Associations of Socioeconomic Status, Public vs Private Insurance, and Race/Ethnicity With Metastatic Sarcoma at Diagnosis

IMPORTANCE

Approximately 10% to 30% of patients with sarcoma present with detectable metastases at diagnosis. However, the extent to which presentation with metastases is due to delayed diagnosis vs other factors remains unclear.

OBJECTIVE

To evaluate whether socioeconomic status, insurance status, or race/ethnicity were associated with the presence of metastases at diagnosis of sarcoma.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study used data from the population-based Surveillance, Epidemiology, and End Results program. Adult and pediatric patients with an initial diagnosis of soft-tissue and bone sarcoma between 2001 and 2015 were stratified by age group (pediatric, <20 years; adult, 20-65 years; older adult, >65 years) and sarcoma subtype. Statistical analyses were performed between August 2019 and January 2020.

EXPOSURES

Surveillance, Epidemiology, and End Results Census tract-level socioeconomic status index, insurance status, and race/ethnicity.

MAIN OUTCOMES AND MEASURES

The odds of presenting with metastases at diagnosis were calculated.

RESULTS

A total of 47 337 patients with first primary malignant sarcoma were included (24 343 male patients [51.4%]), with 29 975 non-Hispanic White patients (63.3%), 5673 non-Hispanic Black patients (12.0%), 7504 Hispanic patients (15.8%), and 4185 American Indian-Alaskan Native and Asian Pacific Islander patients (8.8%). Liposarcoma in adults was the only subtype and age group combination that demonstrated a significant trend in incidence across socioeconomic status levels (odds ratio, 0.85; 99% CI, 0.76-0.96; P = .001). However, compared with having non-Medicaid insurance, having Medicaid or no insurance in adults was associated with an increased odds of metastases at diagnosis for 6 of the 8 sarcoma subtypes evaluated; osteosarcoma and Ewing sarcoma were the only 2 subtypes in adults for which metastases were not associated with insurance status. In addition, there was an increased risk of presenting with metastases among non-Hispanic Black adults diagnosed with leiomyosarcoma (odds ratio, 1.87; 99% CI, 1.41-2.48) and unclassified sarcomas (odds ratio, 1.65; 99% CI, 1.01-2.67) compared with non-Hispanic White adults that was independent of socioeconomic and insurance status.

CONCLUSIONS AND RELEVANCE

These findings suggest that delayed access to care is associated with advanced stage at diagnosis for several soft-tissue sarcoma subtypes in adults, whereas other factors may be associated with the metastatic progression of osteosarcoma and Ewing sarcoma, as well as the racial disparities observed with metastatic leiomyosarcoma and unclassified sarcomas.