Effect of Unplanned Therapy on the Prognosis of Patients with Extremity Osteosarcoma

Trends in Diagnosis and Surgical Treatment of Bone Metastases among Orthopedic Surgeons

Background: The proper diagnosis and treatment of bone metastases are essential for patient survival. However, several strategies for the treatment are practiced. Therefore, the aim of the study was to analyze what factors influence the choice of a method of treatment. Methods: An online survey was conducted within the Polish Society of Orthopedics and Traumatology. It consisted of 45 questions and was divided into four main parts: Participant Characteristics, Diagnosis and Qualification, Treatment, and Clinical Cases. Results: A total number of 104 responses were collected. The most frequently chosen methods were: Intramedullary nail (IMN) + Resection + Polymethyl methacrylate (PMMA) (30.47%) and IMN without tumor resection (42.13%), and in third place, modular endoprosthesis (17.25%). The less experienced group of orthopedic surgeons more often (47.5% vs. 39.5%) decided to perform IMN without tumor resection than the more experienced group (p = 0.046). Surgeons from district hospitals less frequently (13.7% vs. 23.1%) would decide to use modular endoprosthesis than surgeons from university hospitals (p = 0.000076). Orthopedists who performed ≥ 11 bone metastases surgeries per year would more often use modular endoprosthesis (34.8% vs. 13.2%) than those who performed ≤ 10 operations per year (p = 0.000114). Conclusion: Experience, place of work, and the number of metastasis surgeries performed during a year may influence the choice of treatment method in patients with bone metastases.

Resource-appropriate selection of osteosarcoma treatment protocols in low- and middle-income countries

Osteosarcoma is a rare malignancy; however, it is still the most common primary bone tumor in adolescents and young adults. Chemotherapy improves survival indubitably in osteosarcoma; nevertheless, the concern is the stagnant progress since the last several decades. There are a handful of active agents and unresolved issues, especially in choosing the ideal chemotherapy regimen. The oncology community is in equipoise regarding the position of high-dose methotrexate (HDMTX), mandatory or adjunct. The choice of therapy becomes widely relevant, including in low- and middle-income countries (LMIC), where HDMTX administration brings additional complexities. Research into novel non-HDMTX-based protocols adapted to the available resources is pivotal in improving disease outcomes, especially in LMIC. The current review focuses on real-world challenges in decision-making and provides a comprehensive overview of the evolution of treatment protocols in LMIC.

Extracellular Vesicles in Osteosarcoma: Antagonists or Therapeutic Agents?

Osteosarcoma (OS) is a skeletal tumor affecting mainly children and adolescents. The presence of distance metastasis is frequent and it is localized preferentially to the lung, representing the main reason for death among patients. The therapeutic approaches are based on surgery and chemotherapeutics. However, the drug resistance and the side effects associated with the chemotherapy require the identification of new therapeutic approaches. The understanding of the complex biological scenario of the osteosarcoma will open the way for the identification of new targets for its treatment. Recently, a great interest of scientific community is for extracellular vesicles (EVs), that are released in the tumor microenvironment and are important regulators of tumor proliferation and the metastatic process. At the same time, circulating extracellular vesicles can be exploited as diagnostic and prognostic biomarkers, and they can be loaded with drugs as a new therapeutic approach for osteosarcoma patients. Thus, the characterization of OS-related EVs could represent a way to convert these vesicles from antagonists for human health into therapeutic and/or diagnostic agents.

CircRNA-miRNA networks in regulating bone disease

Circular RNA (circRNA) is a class of endogenous noncoding RNA (ncRNA), presenting as a special covalent closed loop without a 5' cap or 3' tail, maintaining resistance to RNA exonuclease and keeping high stability. Although lowly expressed in most situations, circRNA makes an active difference in regulating physiological or pathological processes by modulating gene expression by regulation of transcription, protein, and miRNA functions through various mechanisms in particular tissues. Recent studies have demonstrated the roles of the miRNA-circRNA network in the development of several bone diseases such as osteoporosis, a multiple-mechanism disease resulting from defective bone quality and low bone mass, osteoarthritis, whose main pathomechanism is inflammation and articular cartilage degradation, as well as osteosarcoma, known as one of the most common bone cancers. However, the specific mechanism of how circRNA along with miRNA influences those diseases is not well documented, showing potential for the development of new therapies for those bone diseases.

Circular RNA circPDSS1 promotes osteosarcoma progression by sponging miR-502-3p and miR-4436a

Osteosarcoma (OS) is a highly aggressive bone cancer. Patients with OS frequently develop drug resistance in clinical treatment, and the prognosis has not been improved significantly. There is an urgent need to identify novel markers and therapeutic targets. In this study, we focused on the highly expressed noncoding circular RNA circPDSS1 in OS, and studied its functional roles and downstream targets in OS cells by CCK-8, clone formation assay, transwell assays. Additionally, we performed luciferase reporter assay, RNA pull-down experiment and qRT-PCR to validate the micoRNA targets of circPDSS1. The involvement of circPDSS1 in tumorigenesis was also investigated in mouse xenografts model. The expression of circPDSS1 was significantly upregulated in OS tissues and cell lines. Patients with high circPDSS1 expression were associated with poorer progression-free survival (PFS) and overall survival (OS) as compared to those with low circPDSS1 expression. CircPDSS1 knockdown significantly inhibited the viability, clone formation ability and invasion ability of OS cells, and induced cell apoptosis, which were associated with the upregulation of proapoptotic proteins and the impairment of prosurvival signaling. Molecular mechanism study further demonstrated that circPDSS1 modulates OS cell functions by regulating the expression of miR-502-3p and miR-4436a. Our data suggest that circPDSS1 acts as a molecular sponge of miR-502-3p and miR-4436a regulates the proliferation and invasion of OS cells and promote the malignant progression of OS.

Intestinal Dysbiosis Correlates With Sirolimus-induced Metabolic Disorders in Mice

BACKGROUND

Long-time use of pharmacological immunosuppressive agents frequently leads to metabolic disorders. Most studies have focused on islet toxicity leading to posttransplantation diabetes mellitus. In contrast, the link between intestinal dysbiosis and immunosuppressive drug-induced metabolic disorders remains unclear.

METHODS

We established a mouse model of metabolic abnormality via sirolimus treatment. Fecal microbiota was examined using 16S rRNA gene MiSeq sequencing. Intestinal barrier function was assessed using fluorescein isothiocyanate-dextran assay and mucus immunostaining. Systemic inflammation was determined using a multiplexed fluorescent bead-based immunoassay.

RESULTS

Sirolimus induced dyslipidemia and glucose intolerance in mice in a dose-dependent manner. Interestingly, the clinical-mimicking dose of sirolimus altered the intestinal microbiota community, which was characterized by the enrichment of Proteobacteria, depletion of Akkermansia, and potential function shifts to those involved in lipid metabolism and the immune system. In addition, the clinical-mimicking dose of sirolimus reduced the thickness of the intestinal mucosal layer, increased the intestinal permeability, and enriched the circulating pro-inflammatory factors, including interleukin (IL)-12, IL-6, monocyte chemotactic protein 1, granulocyte-macrophage colony stimulating factor, and IL-1β. Our results showed a close association between intestinal dysbiosis, intestinal barrier failure, systemic inflammation, and metabolic disorders. Furthermore, we demonstrated that oral intervention in the gut microbiota by Lactobacillus rhamnosus HN001 protected against intestinal dysbiosis, especially by depleting the lipopolysaccharide-producing Proteobacteria, and attenuated the sirolimus-induced systemic inflammation, dyslipidemia, and insulin resistance.

CONCLUSIONS

Our study demonstrated a potentially causative role of intestinal dysbiosis in sirolimus-induced metabolic disorders, which will provide a novel therapeutic target for transplant recipients.

Standard Treatment Remains the Recommended Approach for Patients with Bone Sarcoma Who Underwent Unplanned Surgery: Report from the Japanese Musculoskeletal Oncology Group

Background

The outcomes of unplanned surgery for bone sarcomas have not been frequently discussed. However, it is important to recognize patterns, treatment, and clinical outcomes of unplanned surgeries for patients with bone sarcomas. This multicenter study aimed to characterize the clinical outcomes of patients with bone sarcomas who underwent unplanned surgeries.

Patients and Methods

Data of 43 patients with bone sarcomas who underwent unplanned surgery between 2006 and 2017 were obtained from 23 hospitals in Japan. These included 18 cases of osteosarcoma, 9 of Ewing sarcoma, 8 of chondrosarcoma, and 6 of undifferentiated pleomorphic sarcoma. The study included 28 men and 15 women, with a mean age of 46 years. The mean follow-up duration was 59 months.

Results

The main primary tumor sites were the femur (n = 19), spine (n = 6), pelvis (n = 5), tibia (n = 3), and humerus (n = 3). The primary diagnoses were benign bone tumor (n = 24), trauma (n = 7), bone metastasis (n = 5), osteomyelitis (n = 4), degeneration (n=2), and unknown (n = 1). As unplanned surgeries, curettage, with or without bone graft, was performed in 26 patients; internal fixation was performed in 7; spinal surgery in 5; arthroplasty in 4; and arthroscopy in one. Thirty-eight patients received additional standard treatments. Thirty-four of these patients underwent surgical tumor resections, including amputation (n = 10), and the remaining 4 received radiotherapy or carbon ion radiotherapy as additional standard treatments. The 5-year disease-specific survival (DSS) rates in patients with osteosarcoma, Ewing sarcoma, and chondrosarcoma were 65.5%, 58.3%, and 72.9%, respectively. Twelve (27.9%) patients developed local recurrences (LR); among the total 43 patients studied, the 5-year DSS rates were significantly worse for those who developed LR compared to those who did not (p = 0.03). The 5-year DSS rates in patients with and without LR were 44% and 73.8%, respectively.

Conclusion

We recommend that patients who have undergone unplanned surgery be administered standard treatment, including the option of amputation because herein, LR was shown to be a risk factor for decreased DSS.

"Whoops" fixation of proximal humerus pathological fracture ended with forequarter amputation - Case report

INTRODUCTION

Even with the advancement of limb salvage surgery techniques, forequarter amputation (FQA) is still used in orthopedic oncology. Even though it might pose catastrophic sequelae on the patient's lifestyle, debilitating one's ability to perform regular tasks, FQA is still considered as a treatment of last resort for huge fungating tumors of the upper extremity.

CASE PRESENTATION

We present a case of an 18-year-old male patient, who was diagnosed in Libya with left proximal humerus fracture after a trivial trauma and underwent open reduction and internal fixation using k-wires as it was thought to be a simple fracture. Soon after, pain and swelling progressed severely and an open biopsy confirmed a diagnosis of osteosarcoma and imaging suggested metastatic disease to the lungs for which he was started on chemoradiotherapy. He was referred to our cancer center to continue his management and due to the aggressive nature of the tumor, the patient underwent palliative forequarter amputation followed by multiple lines of chemotherapy and radiotherapy, all of which failed to halt the progression of the disease. The patient was lost to follow up due to his decision to go back to Libya.

CONCLUSION

"Whoops" surgeries are fixated upon repairing fractures without looking for the alarming signs on radiographs to exclude pathological entity. As in our case, the procedure done escalated the osteosarcoma into such a massive fungating tumor due to the violation of the osteosarcoma pseudo capsule, in which the only available option is to do a palliative forequarter amputation.

Overexpression of hsa_circ_0136666 predicts poor prognosis and initiates osteosarcoma tumorigenesis through miR-593-3p/ZEB2 pathway

Background: Osteosarcoma (OS) is a type of malignant bone tumor with a growing incidence. Increasing studies indicate circular RNA (circRNA) has a vital function in tumorigenesis. Yet, how circRNA regulates OS development is not clear. In the present work, we aimed to investigate the roles of hsa_circ_0136666 in OS progression.

Results: hsa_circ_0136666 was shown to be upregulated in OS and correlated with advanced stage and poor prognosis. Functional investigation using CCK8, colony formation assay and Transwell assay demonstrated that hsa_circ_0136666 promoted OS proliferation, migration and invasion, but inhibited cell death. Additionally, we identified hsa_circ_0136666 was a molecular sponge for miR-593-3p to facilitate ZEB2 expression. MiR-593-3p and ZEB2 were inversely expressed in OS tissues. And hsa_circ_0136666 exerts oncogenic roles in OS relying on miR-593-3p and ZEB2.

Conclusion: Our results demonstrate the involvement of hsa_circ_0136666 in regulating OS tumorigenesis and it may be a therapeutic target.

Methods: The expression of hsa_circ_0136666 was analyzed by qRT-PCR in OS tissues and cell lines. Proliferation was measured via CCK8 and colony formation assays. Migration and invasion were determined through Transwell assay. Luciferase reporter assay was utilized to determine the interaction between hsa_circ_0136666 and miR-593-3p or between miR-593-3p and ZEB2. Animal experiment was performed to investigate the role of hsa_circ_0136666 in vivo.

Selective Activation of ZAK β Expression by 3-Hydroxy-2-Phenylchromone Inhibits Human Osteosarcoma Cells and Triggers Apoptosis via JNK Activation

Although various advancements in radical surgery and neoadjuvant chemotherapy have been developed in treating osteosarcoma (OS), their clinical prognosis remains poor. A synthetic chemical compound, 3-hydroxylflavone, that is reported to regulate ROS production is known to inhibit human bone osteosarcoma cells. However, its role and mechanism in human OS cells remains unclear. In this study, we have determined the potential of 3-Hydroxy-2-phenylchromone (3-HF) against OS using human osteosarcoma (HOS) cells. Our previous studies showed that Zipper sterile-alpha-motif kinase (ZAK), a kinase member of the MAP3K family, was involved in various cellular events such as cell proliferation and cell apoptosis, and encoded two transcriptional variants, ZAKα and β. In this study, we show that 3-HF induces the expression of ZAK and thereby enhances cellular apoptosis. Using gain of function and loss of function studies, we have demonstrated that ZAK activation by 3-HF in OS cells is confined to a ZAKβ form that presumably plays a leading role in triggering ZAKα expression, resulting in an aggravated cancer apoptosis. Our results also validate ZAKβ as the predominant form of ZAK to drive the anticancer mechanism in HOS cells.

Anti-osteosarcoma property of decorin-modified titanium surface: A novel strategy to inhibit oncogenic potential of osteosarcoma cells

Osteosarcoma is the most common bone sarcoma in adolescents. Decorin (DCN) has been proposed to be a new anti-osteosarcoma therapeutic strategy. Our previous study has loaded decorin on titanium (Ti) surface by polydopamine (DOPA) as an anchor to enhance osseointegration. In this study, we investigated the effect of decorin-coated Ti substrates (TI-DOPA-DCN) on the oncogenic potential of osteosarcoma cells SAOS-2. The substrates were placed in 24-well plates for cell culture. Cell viability was determined by Cell Counting Kit-8 (CCK8) assay. Apoptosis was evaluated by DAPI staining and Annexin V-FITC/PI double staining analysis. Cell cycle was analyzed by flow cytometry. Cell migration and invasion were evaluated by Transwell assay. For co-culture, the pre-osteogenic cells MEC3T3-E1 and osteosarcoma cells SAOS-2 were stained with cell membrane fluorescent dyes, and then mixed (1:1) for co-culture. The cells were observed under a fluorescence microscope at four time points of 24, 48, 72, and 96 h. The results showed that TI-DOPA-DCN substrate can selectively inhibit cell proliferation of osteosarcoma cells but not pre-osteoblasts. However, the cell cycle of SAOS-2 was not affected by TI-DOPA-DCN substrates. Both DAPI staining and Annexin V-FITC/PI double staining analysis revealed that TI-DOPA-DCN substrates induced apoptosis of osteosarcoma cells. Transwell assay showed that TI-DOPA-DCN substrates inhibited invasion and migration of osteosarcoma cells. Moreover, TI-DOPA-DCN substrates inhibited the growth of osteosarcoma cells but promoted that of pre-osteoblasts in the coculture system. Taken together, these findings suggested that decorin coating on Ti surface simultaneously inhibited the oncogenic potential of osteosarcoma cells but enhanced cell growth of pre-osteoblasts, which could be applied to surface modification of Ti orthopedic implant.

The circular RNA circ-ITCH acts as a tumour suppressor in osteosarcoma via regulating miR-22

Background: Osteosarcoma (OS) is the most prevailing primary bone tumour and the third prevalent tumour in children and adolescents. Despite advanced treatments, the survival rate of OS has not been effectively improved. Here, we intended to investigate the functional impacts of circ-ITCH on OS. Methods: Circ-ITCH expression in OS tissues and cells was evaluated utilizing qRT-PCR. Viability and proliferation of MG63 and Saos-2 cells were determined by utilizing CCK-8 assay and BrdU assay. Transwell assay was utilized to investigate migration and invasion. Western blot was utilized to distinguish apoptosis and metastasis-related proteins expression. Sequentially, the above-mentioned parameters were reassessed when up-regulating miR-22. Results: Circ-ITCH was low expressed in OS tissues and cells. Overexpressing circ-ITCH facilitated apoptosis and repressed viability, proliferation, migration and invasion in MG63 and Saos-2 cells. MiR-22 expression was reduced by overexpressing circ-ITCH. The decline of viability, proliferation, migration and invasion made by overexpressing circ-ITCH was alleviated by up-regulating miR-22. Conclusively, circ-ITCH suppressed PTEN/PI3K/AKT and SP-1 pathways via down-regulating miR-22. Conclusion: Circ-ITCH took effects on apoptosis, viability, proliferation, migration and invasion through restraining PTEN/PI3K/AKT and SP-1 pathways via down-regulating miR-22 in MG63 and Saos-2 cells. Highlights Low expression of circ-ITCH is observed in osteosarcoma tissues and cell lines; Overexpression circ-ITCH suppresses miR-22 expression; Circ-ITCH promotes proliferation and represses apoptosis by up-regulating miR-22; Circ-ITCH promotes migration and invasion by up-regulating miR-22; Circ-ITCH activates PTEN/PI3K/AKT and SP-1 pathways by up-regulating miR-22.

Fisetin activates Hippo pathway and JNK/ERK/AP-1 signaling to inhibit proliferation and induce apoptosis of human osteosarcoma cells via ZAK overexpression

Osteosarcoma (OS) is a tumor entity that can cause a large number of cancer-related deaths. Although chemotherapy can decrease proliferation and increase apoptosis of human OS cells, the clinical prognosis remains poor. Fisetin is a flavonol found in fruits and vegetables and is reported to inhibit cell growth in numerous cancers. But the molecular mechanism underlying fisetin in human OS cells is not clear. It is known that sterile-alpha motif and leucine zipper containing kinase (ZAK), a kinase in the MAP3K family, is involved in various cell processes, including proliferation and apoptosis. In our lab, we have demonstrated that overexpression of ZAK can induce apoptosis in human OS cells. In the previous studies, MAP4K, the upstream of MAP3K, can act in parallel to MST1/2 to activate LATS1/2 in the Hippo pathway. Turning on the Hippo pathway can decrease proliferation and otherwise cause cell apoptosis in cancer cells. In this study, we found that fisetin can upregulate ZAK expression to induce the Hippo pathway and mediate the activation of JNK/ERK, the downstream of ZAK, to trigger cell apoptosis via AP-1 dependent manner in human OS cells. These findings reveal a novel molecular mechanism underlying fisetin effect on human OS cells.

Treatment-Related Prognostic Factors in Managing Osteosarcoma around the Knee with Limb Salvage Surgery: A Lesson from a Long-Term Follow-Up Study

Purpose

The aim of this study was to assess the treatment-related factors associated with local recurrence and overall survival of patients with osteosarcoma treated with limb-salvage surgery.

Patients and Methods

Treatment-related factors were analyzed to evaluate their effects on local recurrence-free survival (LRFS) and overall survival (OS) in 182 patients from 2004 to 2013.

Results

The mean length of follow-up was 73.4 ± 34.7 months (median, 68 months; range, 12-173 months), and 63 patients died by the end of the follow-up. The 5-year and 10-year overall survival rates were 68.6 ± 6.6% and 59.4 ± 10.6%, respectively. Univariate analysis showed that treatment-related prognostic factors for overall survival were prolonged symptom intervals >=60 days, biopsy/tumor resection performed by different centers, previous medical history, incomplete preoperative chemotherapy (<8 weeks), and prolonged postoperative interval >21 days. In the multivariate analysis, biopsy/tumor resection performed by different centers, incomplete implementation of planned new adjuvant chemotherapy, and delayed resumption of postoperative chemotherapy (>21 days) were risk factors for poor prognosis; biopsy/tumor resection performed by different centers and tumor necrosis <90% were independent predictors of local recurrence.

Conclusion

For localized osteosarcoma treated with limb-salvage surgery, it is necessary to optimize timely standard chemotherapy and to resume postoperative chemotherapy to improve survival rates. Biopsies should be performed at experienced institutions in cases of developing local recurrence.

Upregulation of circular RNA circ_0000502 predicts unfavorable prognosis in osteosarcoma and facilitates cell progression via sponging miR-1238

Growing evidence suggests that circular RNAs (circRNAs) play a significant role in regulating cancer initiation and metastasis. Osteosarcoma (OS) is a sophisticated disease with various genes activated or silenced. In this study, we defined a novel cancer-related circRNA, circ_0000502 in OS progression. qRT-PCR was conducted to detect its expression level in OS tissue samples and cell lines. In addition, the clinical significance of circ_0000502 was investigated. Afterwards, gain-of-function and loss-of-function in vitro assays were performed to detect the cell growth, apoptosis, migration, and invasion altered by circ_0000502 by CCK-8, clone-forming, flow cytometry, and transwell experiments. Xenograft study was performed to validate the in vitro data. The luciferase reporter assay was used to explore the mechanism of circ_0000502. Circ_0000502 was identified upregulated in both OS tissue specimens and cells. In addition, its expression predicts clinical severity and unfavorable prognosis in the 63 recruited patients with OS. Circ_0000502 facilitated cell proliferation, migration, and invasion in OS cells and inhibited cell apoptosis. The animal study further confirmed the in vitro results. For mechanism exploration, circ_0000502 could directly sponge microRNA (miR)-1238, and the oncogenic functions of circ_0000502 is partially dependent on its regulation of miR-1238 proved by rescue assays. In summary, this study might help to develop rational predictive and therapeutic target for patients with OS.

Circular RNA circNASP modulates the malignant behaviors in osteosarcoma via miR-1253/FOXF1 pathway

Increasing evidences demonstrate that circular RNAs (circRNAs) serve as essential regulators in various human diseases, including cancer. However, the study on circRNA function in osteosarcoma (OS) is just emerging. In the present study, we screened out a novel circRNA termed circNASP which was significantly upregulated in OS tissues compared to adjacent normal tissues. We found that circNASP knockdown dramatically inhibited the proliferation, cell cycle progression and invasion of OS cells. Moreover, we showed that circNASP expression was positively correlated with tumor size and metastasis in OS patients. In terms of mechanism, we found that circNASP acts as a sponge of miR-1253 targeting FOXF1 in OS cells. By inhibiting miR-1253 availability, circNASP promoted FOXF1 expression. Rescue assays indicated that inhibition of miR-1253 could significantly reverse the effects of circNASP knockdown on OS cell proliferation and invasion while restoration of FOXF1 rescued the proliferation and invasion of OS cells transfected with miR-1253 mimics. Taken together, our findings demonstrated that circNASP contributes to malignant behaviors of OS cells by miR-1253/FOXF1 pathway, which suggested circNASP/miR-1253/FOXF1axis might be a potential therapeutic target.

Circular RNA hsa_circ_0001564 regulates osteosarcoma proliferation and apoptosis by acting miRNA sponge

Circular RNAs (circRNAs) is a novel type of non-coding RNAs generated from back splicing, which has been verified to mediate multiple tumorigenesis. However, the role of circRNA in osteosarcoma is still unclear. In the present study, we preliminarily screened the circRNAs expression profiles in osteosarcoma and investigated the potential regulation mechanism. The circRNAs expression profiles in osteosarcoma were screened using circRNA microarray analysis, and results showed that there were 1152 circRNAs up-regulated and 915 circRNAs down-regulated in tumor tissue compared to adjacent tissue. Hsa_circ_0001564, located at 5q35.3 and its associated-gene symbol is CANX, was one of the significantly overexpressed circRNAs in osteosarcoma tissue, as well as in osteosarcoma cell lines. In functional experiments, hsa_circ_001564 knockdown significantly suppressed the proliferation activity, induced cell cycle arrest in G0/G1 phase, and promoted apoptosis in HOS and MG-63 cells. Subsequently, we explored the probable mechanism of hsa_circ_001564, and fortunately, bioinformatics analysis revealed that miR-29c-3p contained the complementary binding region with hsa_circ_0001564, which was confirmed by dual-luciferase reporter assay. Moreover, rescue experiments illustrated that miR-29c-3p could reverse the oncogenesis effect of hsa_circ_001564. Our study discovers that hsa_circ_0001564 acts as miR-29c-3p sponge to mediate the tumorigenicity, which could act as a potential biomarker for the osteosarcoma and provide a novel insight for competing endogenous RNAs (ceRNAs) mechanism in osteosarcoma.

WITHDRAWN: Circular RNA hsa_circ_0001564 facilitates tumorigenesis of osteosarcoma via sponging miR-29c-3p

The title, author names and abstract of this article were released onto PubMed, despite the fact that the full article was never published in the journal, having been withdrawn by the author. The entry for the paper has now been withdrawn from PubMed by the publisher.