Tumor Syndromes Predisposing to Osteosarcoma

How to distinguish a benign from a malignant tumour in children and when should a biopsy be done and by whom

Bone tumours are frequent in children but most of them are benign. Moreover, the incidence and type of tumours differ from those of adults. As an orthopaedic surgeon, we will likely encounter a bone lesion in a child and we must be able to distinguish if it is a benign lesion or has malignant characteristics and it is necessary to refer it to a centre specialized in tumours. We will discuss the key points we would have to ask in the medical history, look at the physical examination and the radiological characteristics that will allow us to distinguish between a benign and a malignant bone lesion in a child. When there are doubts about the malignancy of a bone lesion or if the diagnosis is not clear, a biopsy should be performed following certain rules in a specialized centre.

From biology to personalized medicine: recent knowledge in Osteosarcoma

High-grade osteosarcoma is the most common paediatric bone cancer. More than one third of patients relapse and die of osteosarcoma using current chemotherapeutic and surgical strategies. To improve outcomes in osteosarcoma, two crucial challenges need to be tackled: 1-the identification of hard-to-treat disease, ideally from diagnosis; 2- choosing the best combined or novel therapies to eradicate tumor cells which are resistant to current therapies leading to disease dissemination and metastasize as well as their favorable microenvironment. Genetic chaos, tumor complexity and heterogeneity render this task difficult. The development of new technologies like next generation sequencing has led to an improvement in osteosarcoma oncogenesis. This review summarizes recent biological and therapeutical advances in osteosarcoma, as well as the challenges that must be overcome in order to develop personalized medicine and new therapeutic strategies and ultimately improve patient survival.

Prognostic and predictive biomarkers in head and neck cancer: something old, something new, something borrowed, something blue and a sixpence in your shoe

A biomarker is a measurable indicator of biological or pathological processes or the response to an exposure or intervention and is used to guide management decisions. In head and neck pathology, biomarkers are assessed by histological criteria and immunohistochemical and molecular studies. Surgical resection remains the mainstay of management of many head and neck malignancies. Adjuvant radiotherapy and/or systemic therapy may be administered depending on the presence of adverse prognostic factors identified on histopathological or immunohistochemical examination. In this review, we outline the clinically relevant prognostic and predictive factors in head and neck malignancies including conventionally recognised factors such as tumour size, depth of invasion, lymphovascular and perineural invasion and margin status as well as novel evolving factors such as recurrent genetic rearrangements and assessment of immune checkpoints. Practical issues are discussed to assist with recognising and reporting of these factors. A summary of useful tools such as structured pathology report formats is also included to assist with comprehensive reporting of all clinically relevant parameters, minimise risk and improve workflow efficiencies.

Unveiling the Protective Role of Melatonin in Osteosarcoma: Current Knowledge and Limitations

Melatonin, an endogenous neurohormone produced by the pineal gland, has received increased interest due to its potential anti-cancer properties. Apart from its well-known role in the sleep-wake cycle, extensive scientific evidence has shown its role in various physiological and pathological processes, such as inflammation. Additionally, melatonin has demonstrated promising potential as an anti-cancer agent as its function includes inhibition of tumorigenesis, induction of apoptosis, and regulation of anti-tumor immune response. Although a precise pathophysiological mechanism is yet to be established, several pathways related to the regulation of cell cycle progression, DNA repair mechanisms, and antioxidant activity have been implicated in the anti-neoplastic potential of melatonin. In the current manuscript, we focus on the potential anti-cancer properties of melatonin and its use in treating and managing pediatric osteosarcoma. This aggressive bone tumor primarily affects children and adolescents and is treated mainly by surgical and radio-oncological interventions, which has improved survival rates among affected individuals. Significant disadvantages to these interventions include disease recurrence, therapy-related toxicity, and severe/debilitating side effects that the patients have to endure, significantly affecting their quality of life. Melatonin has therapeutic effects when used for treating osteosarcoma, attributed to its ability to halt cancer cell proliferation and trigger apoptotic cell death, thereby enhancing chemotherapeutic efficacy. Furthermore, the antioxidative function of melatonin alleviates harmful side effects of chemotherapy-induced oxidative damage, aiding in decreasing therapeutic toxicities. The review concisely explains the many mechanisms by which melatonin targets osteosarcoma, as evidenced by significant results from several in vitro and animal models. Nevertheless, if further explored, human trials remain a challenge that could shed light and support its utility as an adjunctive therapeutic modality for treating osteosarcoma.

Pyroptosis-Related Gene Signature Predicts Prognosis and Response to Immunotherapy and Medication in Pediatric and Young Adult Osteosarcoma Patients

Purpose

Pyroptosis, a new form of inflammatory programmed cell death, has recently gained attention. However, the impact of the expression levels of pyroptosis-related genes (PRGs) on the overall survival (OS) of osteosarcoma patients remains unclear. This study aims to investigate the impact of the expression levels of PRGs on the OS of pediatric and young adult patients with osteosarcoma.

Patients and Methods

Transcriptome matrix datasets of normal muscle or skeletal tissues from the Genotype-Tissue Expression (GTEx) project and osteosarcoma specimen the National Cancer Institute's (NCI) Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database were used to identify pyroptosis-related genes (PRGs) associated with prognosis. The National Center for Biotechnology Information's (NCBI) GSE21257 dataset was employed to validate the predictive value of the pyroptosis-related signature (PRS). Additionally, reverse transcription polymerase chain reaction (RT-qPCR) experiment was performed in normal and osteosarcoma cell lines.

Results

The study identified 18 differentially expressed PRGs (DEPRGs) between normal muscle or skeletal tissues and tumor samples. Multiple machine learning techniques were used to select PRGs, resulting in the identification of four hub PRGs. A PRS-score was calculated for each sample based on the expression of these four hub PRGs, and samples were categorized into low and high PRS-score level groups. It was confirmed that metastatic status and PRS-score level are independent prognostic predictors. A nomogram model for predicting OS of osteosarcoma patients was constructed. Single-cell RNA-sequencing data display the expression patterns of the hub PRGs. RT-qPCR data results were found to be consistent with the differential expression analysis performed on TARGET and GTEx samples.

Conclusion

The study developed a novel pyroptosis-related gene signature that can stratify pediatric and young adult osteosarcoma patients into different risk groups, thus predicting their response to immunotherapy and chemotherapy.

Prevalence and clinical implications of germline pathogenic variants in cancer predisposing genes in young patients across sarcoma subtypes

BACKGROUND

Sarcomas are a rare and diverse group of cancers occurring mainly in young individuals for which an underlying germline genetic cause remains unclear in most cases.

METHODS

Germline DNA from 177 children, adolescents and young adults with soft tissue or bone sarcomas was tested using multigene panels with 113 or 126 cancer predisposing genes (CPGs) to describe the prevalence of germline pathogenic/likely pathogenic variants (GPVs). Subsequent testing of a subset of tumours for loss of heterozygosity (LOH) evaluation was performed to investigate the clinical and molecular significance of these variants.

RESULTS

GPVs were detected in 21.5% (38/177) of the patients (15.8% in children and 21.6% in adolescents and young adults), with dominant CPGs being altered in 15.2% overall. These variants were found in genes previously associated with the risk of developing sarcomas (TP53, RB1, NF1, EXT1/2) but also in genes where that risk is still emerging/limited (ERCC2, TSC2 and BRCA2) or unknown (PALB2, RAD50, FANCM and others). The detection rates of GPVs varied from 0% to 33% across sarcoma subtypes and GPV carriers were more likely to present more than one primary tumour than non-carriers (21.1%×6.5%; p=0.012). Loss of the wild-type allele was detected in 48% of tumours from GPV carriers, mostly in genes definitively associated with sarcoma risk.

CONCLUSION

Our findings reveal that a high proportion of young patients with sarcomas presented a GPV in a CPG, underscoring the urgency of establishing appropriate genetic screening strategies for these individuals and their families.

Synchronous gnathic osteosarcoma and B-cell lymphoblastic lymphoma/leukemia: A rare case presentation

Multiple primary malignancies are a well-recognized entity, with increased recognition and detection alongside development of hybrid imagining. We present a rare case of a 16-year-old male with gnathic osteosarcoma and incidental finding of a second silent synchronous B-cell lymphoblastic lymphoma/leukemia in the lower limb. Treated successfully by chemotherapy, radiotherapy, and surgery.

Versatile function of AMPK signaling in osteosarcoma: An old player with new emerging carcinogenic functions

AMP-activated protein kinase (AMPK) signaling has a versatile role in Osteosarcoma (OS), an aggressive bone malignancy with a poor prognosis, particularly in cases that have metastasized or recurred. This review explores the regulatory mechanisms, functional roles, and therapeutic applications of AMPK signaling in OS. It focuses on the molecular activation of AMPK and its interactions with cellular processes like proliferation, apoptosis, and metabolism. The uncertain role of AMPK in cancer is also discussed, highlighting its potential as both a tumor suppressor and a contributor to carcinogenesis. The therapeutic potential of targeting AMPK signaling in OS treatment is examined, including direct and indirect activators like metformin, A-769662, resveratrol, and salicylate. Further research is needed to determine dosing, toxicities, and molecular mechanisms responsible for the anti-osteosarcoma effects of these compounds. This review underscores the complex involvement of AMPK signaling in OS and emphasizes the need for a comprehensive understanding of its molecular mechanisms. By elucidating the role of AMPK in OS, the aim is to pave the way for innovative therapeutic approaches that target this pathway, ultimately improving the prognosis and quality of life for OS patients.

Osteosarcoma in Pediatric and Adult Populations: Are Adults Just Big Kids?

Malignant bone tumors are commonly classified as pediatric or adolescent malignancies, and clinical trials for these diseases have generally focused on these populations. Of primary bone cancers, osteosarcoma is among the most common. Osteosarcoma has a bimodal age distribution, with the first peak occurring in patients from 10 to 14 years old, and the second peak occurring in patients older than 65, with about 25% of cases occurring in adults between 20 and 59 years old. Notably, adult osteosarcoma patients have worse outcomes than their pediatric counterparts. It remains unclear whether age itself is a poor prognostic factor, or if inherent differences in tumor biology exist between age groups. Despite these unknowns, current treatment strategies for adults are largely extrapolated from pediatric studies since the majority of clinical trials for osteosarcoma treatments are based on younger patient populations. In light of the different prognoses observed in pediatric and adult osteosarcoma, we summarize the current understanding of the molecular etiology of osteosarcoma and how it may differ between age groups, hypothesizing why adult patients have worse outcomes compared to children.

Comparative Shotgun Proteomics Reveals the Characteristic Protein Signature of Osteosarcoma Subtypes

Osteosarcoma is a primary malignant bone tumor affecting adolescents and young adults. This study aimed to identify proteomic signatures that distinguish between different osteosarcoma subtypes, providing insights into their molecular heterogeneity and potential implications for personalized treatment approaches. Using advanced proteomic techniques, we analyzed FFPE tumor samples from a cohort of pediatric osteosarcoma patients representing four various subtypes. Differential expression analysis revealed a significant proteomic signature that discriminated between these subtypes, highlighting distinct molecular profiles associated with different tumor characteristics. In contrast, clinical determinants did not correlate with the proteome signature of pediatric osteosarcoma. The identified proteomics signature encompassed a diverse array of proteins involved in focal adhesion, ECM-receptor interaction, PI3K-Akt signaling pathways, and proteoglycans in cancer, among the top enriched pathways. These findings underscore the importance of considering the molecular heterogeneity of osteosarcoma during diagnosis or even when developing personalized treatment strategies. By identifying subtype-specific proteomics signatures, clinicians may be able to tailor therapy regimens to individual patients, optimizing treatment efficacy and minimizing adverse effects.

Multi-Anticancer Activities of Phytoestrogens in Human Osteosarcoma

Phytoestrogens are plant-derived bioactive compounds with estrogen-like properties. Their potential health benefits, especially in cancer prevention and treatment, have been a subject of considerable research in the past decade. Phytoestrogens exert their effects, at least in part, through interactions with estrogen receptors (ERs), mimicking or inhibiting the actions of natural estrogens. Recently, there has been growing interest in exploring the impact of phytoestrogens on osteosarcoma (OS), a type of bone malignancy that primarily affects children and young adults and is currently presenting limited treatment options. Considering the critical role of the estrogen/ERs axis in bone development and growth, the modulation of ERs has emerged as a highly promising approach in the treatment of OS. This review provides an extensive overview of current literature on the effects of phytoestrogens on human OS models. It delves into the multiple mechanisms through which these molecules regulate the cell cycle, apoptosis, and key pathways implicated in the growth and progression of OS, including ER signaling. Moreover, potential interactions between phytoestrogens and conventional chemotherapy agents commonly used in OS treatment will be examined. Understanding the impact of these compounds in OS holds great promise for developing novel therapeutic approaches that can augment current OS treatment modalities.

Identification of New Potential Prognostic and Predictive Markers in High-Grade Osteosarcoma Using Whole Exome Sequencing

Conventional high-grade osteosarcoma (OS) is the most common primary cancer of bone and it typically affects the extremities of adolescents. OS has a complex karyotype, and molecular mechanisms related to carcinogenesis, progression and resistance to therapy are still largely unknown. For this reason, the current standard of care is associated with considerable adverse effects. In this study, our aim was to identify gene alterations in OS patients using whole exome sequencing (WES) to find new potential prognostic biomarkers and therapeutic targets. We performed WES on formalin-fixed paraffin-embedded (FFPE) biopsy materials collected from 19 patients affected by conventional high-grade OS. The clinical and genetic data were analyzed according to response to therapy, presence of metastasis and disease status. By comparing good and poor responders to neoadjuvant therapy, we detected a clear prevalence of mutations in the ARID1A, CREBBP, BRCA2 and RAD50 genes in poor responders that negatively influence the progression-free survival time. Moreover, higher tumor mutational burden values correlated with worse prognosis. The identification of mutations in ARID1A, CREBBP, BRCA2 and RAD50 may support the use of a more specific therapy for tumors harboring these alterations. In particular, BRCA2 and RAD50 are involved in homologous recombination repair, and could thus be used as specific therapy targets of inhibitors of the enzyme Poly ADP Ribose Polymerase (PARP). Finally, tumor mutational burden is found to be a potential prognostic marker for OS.

Management of osteosarcoma of the head and neck

PURPOSE OF REVIEW

There is no clear consensus guideline that specifies the optimum course of treatment for adult head and neck osteosarcoma (HNO) because of its rarity. The review's goal is to examine the most recent research on the presentation, diagnosis, prognosis, and therapy of head and neck osteosarcoma.

RECENT FINDINGS

Due to overlapping symptoms with various benign disorders of the lower jaw and midface bone, these patients present with a noticeable delay. The greatest results for these malignancies can be achieved with surgery with sufficient margins. However, it may not be able to achieve sufficient margins in tumours of the midface and skull base, and the significance of adjuvant radiation/chemotherapy needs to be investigated. The use of adjuvant radiation in instances with an advanced stage, poor prognostic indicators, and inadequate resection is supported by evidence. Nonetheless, there are divergent opinions regarding the advantages of chemotherapy in adjuvant and neoadjuvant conditions, and further multicentric randomized control trials are required to provide robust evidence.

SUMMARY

Multimodality treatments seem to yield better results for advanced HNO with adverse features and incomplete resections.

The regulatory effects of p53 on the typical and atypical ferroptosis in the pathogenesis of osteosarcoma: A systematic review

Study background: As a rare condition, osteosarcoma affects approximately 3% of all cancer patients. Its exact pathogenesis remains largely unclear. The role of p53 in up- and down-regulating atypical and typical ferroptosis in osteosarcoma remains unclear. The primary objective of the present study is investigating the role of p53 in regulating typical and atypical ferroptosis in osteosarcoma.

Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) and the Patient, Intervention, Comparison, Outcome, and Studies (PICOS) protocol were used in the initial search. The literature search was performed in six electronic databases, including EMBASE, Cochrane library of trials, Web of Science, PubMed, Google Scholar, and Scopus Review, using keywords connected by Boolean operators. We focused on studies that adequately defined patient profiles described by PICOS.

Results and discussion: We found that p53 played fundamental up- and down-regulatory roles in typical and atypical ferroptosis, resulting in either advancement or suppression of tumorigenesis, respectively. Direct and indirect activation or inactivation of p53 downregulated its regulatory roles in ferroptosis in osteosarcoma. Enhanced tumorigenesis was attributed to the expression of genes associated with osteosarcoma development. Modulation of target genes and protein interactions, especially SLC7A11, resulted in enhanced tumorigenesis.

Conclusion: Typical and atypical ferroptosis in osteosarcoma were regulatory functions of p53. The activation of MDM2 inactivated p53, leading to the downregulation of atypical ferroptosis, whereas activation of p53 upregulated typical ferroptosis. Further studies should be performed on the regulatory roles of p53 to unmask its possible clinical applications in the management of osteosarcoma.

The Use of Hydrogels for the Treatment of Bone Osteosarcoma via Localized Drug-Delivery and Tissue Regeneration: A Narrative Review

Osteosarcoma is a malignant tumor of bone that leads to poor mortality and morbidity. Management of this cancer through conventional methods involves invasive treatment options that place patients at an increased risk of adverse events. The use of hydrogels to target osteosarcoma has shown promising results both in vitro and in vivo to eradicate tumor cells while promoting bone regeneration. The loading of hydrogels with chemotherapeutic drugs provides a route for site-specific targeted therapy for osteosarcoma. Current studies demonstrate tumor regression in vivo and lysis of tumor cells in vitro when exposed to doped hydrogel scaffolds. Additionally, novel stimuli-responsive hydrogels are able to react with the tissue microenvironment to facilitate the controlled release of anti-tumor drugs and with biomechanical properties that can be modulated. This narrative review of the current literature discusses both in vitro and in vivo studies of different hydrogels, including stimuli-responsive, designed to treat bone osteosarcoma. Future applications to address patient treatment for this bone cancer are also discussed.

Oxidative stress induced by berberine-based mitochondria-targeted low temperature photothermal therapy

Introduction: Mitochondria-targeted low-temperature photothermal therapy (LPTT) is a promising strategy that could maximize anticancer effects and overcome tumor thermal resistance. However, the successful synthesis of mitochondria-targeted nanodrug delivery system for LPTT still faces diverse challenges, such as laborious preparations processes, low drug-loading, and significant systemic toxicity from the carriers. Methods: In this study, we used the tumor-targeting folic acid (FA) and mitochondria-targeting berberine (BBR) derivatives (BD) co-modified polyethylene glycol (PEG)-decorated graphene oxide (GO) to synthesize a novel mitochondria-targeting nanocomposite (GO-PEG-FA/BD), which can effectively accumulate in mitochondria of the osteosarcoma (OS) cells and achieve enhanced mitochondria-targeted LPTT effects with minimal cell toxicity. The mitochondria-targeted LPTT effects were validated both in vitro and vivo. Results: In vitro experiments, the nanocomposites (GO-PEG-FA/BD) could eliminate membrane potential (ΔΨm), deprive the ATP of cancer cells, and increase the levels of reactive oxygen species (ROS), which ultimately induce oxidative stress damage. Furthermore, in vivo results showed that the enhanced mitochondria-targeted LPTT could exert an excellent anti-cancer effect with minimal toxicity. Discussion: Taken together, this study provides a practicable strategy to develop an ingenious nanoplatform for cancer synergetic therapy via mitochondria-targeted LPTT, which hold enormous potential for future clinical translation.

Mitophagy Effects of Protodioscin on Human Osteosarcoma Cells by Inhibition of p38MAPK Targeting NIX/LC3 Axis

Protodioscin (PD) is a steroidal saponin with various pharmacological activities, including neuro-protective, anti-inflammatory, and anti-tumor activities. However, the effect of PD on human osteosarcoma (OS) cells is unclear. In this study, we found that PD significantly inhibits the growth of human HOS and 143B OS cells through the upregulation of apoptotic-related proteins (cleaved caspase-3, cleaved caspase-9, and cleaved PARP) and mitophagy-related proteins (LC3B and NIX), which contribute to the induction of apoptosis, and MMP (mitochondrial membrane potential) dysfunction and mitophagy. The inhibition of LC3 or NIX was shown to decrease apoptosis and mitophagy in PD-treated OS cells. The knockdown of p38MAPK by siRNA decreased mitochondrial dysfunction, autophagy, mitophagy, and the NIX/LC3B expression in the PD-treated OS cells. A binding affinity analysis revealed that the smaller the KD value (-7.6 Kcal/mol and -8.9 Kcal/mol, respectively), the greater the binding affinity in the PD-NIX and PD-LC3 complexes. These findings show the inhibitory effects of PD-induced mitophagy in human OS cells and may represent a novel therapeutic strategy for human OS, by targeting the NIX/LC3 pathways.

The role of miR-128 in cancer development, prevention, drug resistance, and immunotherapy

A growing body of evidence has revealed that microRNA (miRNA) expression is dysregulated in cancer, and they can act as either oncogenes or suppressors under certain conditions. Furthermore, some studies have discovered that miRNAs play a role in cancer cell drug resistance by targeting drug-resistance-related genes or influencing genes involved in cell proliferation, cell cycle, and apoptosis. In this regard, the abnormal expression of miRNA-128 (miR-128) has been found in various human malignancies, and its verified target genes are essential in cancer-related processes, including apoptosis, cell propagation, and differentiation. This review will discuss the functions and processes of miR-128 in multiple cancer types. Furthermore, the possible involvement of miR-128 in cancer drug resistance and tumor immunotherapeutic will be addressed.

Osteosarcoma

Osteosarcoma is the most common primary malignant tumour of the bone. Osteosarcoma incidence is bimodal, peaking at 18 and 60 years of age, and is slightly more common in males. The key pathophysiological mechanism involves several possible genetic drivers of disease linked to bone formation, causing malignant progression and metastasis. While there have been significant improvements in the outcome of patients with localized disease, with event-free survival outcomes exceeding 60%, in patients with metastatic disease, event-free survival outcomes remain poor at less than 30%. The suspicion of osteosarcoma based on radiographs still requires pathological evaluation of a bone biopsy specimen for definitive diagnosis and CT imaging of the chest should be performed to identify lung nodules. So far, population-based screening and surveillance strategies have not been implemented due to the rarity of osteosarcoma and the lack of reliable markers. Current screening focuses only on groups at high risk such as patients with genetic cancer predisposition syndromes. Management of osteosarcoma requires a multidisciplinary team of paediatric and medical oncologists, orthopaedic and general surgeons, pathologists, radiologists and specialist nurses. Survivors of osteosarcoma require specialized medical follow-up, as curative treatment consisting of chemotherapy and surgery has long-term adverse effects, which also affect the quality of life of patients. The development of osteosarcoma model systems and related research as well as the evaluation of new treatment approaches are ongoing to improve disease outcomes, especially for patients with metastases.

Towards the Search for Potential Biomarkers in Osteosarcoma: State-of-the-Art and Translational Expectations

Osteosarcoma represents a rare cause of cancer in the general population, accounting for <1% of malignant neoplasms globally. Nonetheless, it represents the main cause of malignant bone neoplasm in children, adolescents and young adults under 20 years of age. It also presents another peak of incidence in people over 50 years of age and is associated with rheumatic diseases. Numerous environmental risk factors, such as bone diseases, genetics and a history of previous neoplasms, have been widely described in the literature, which allows monitoring a certain group of patients. Diagnosis requires numerous imaging tests that make it possible to stratify both the local involvement of the disease and its distant spread, which ominously determines the prognosis. Thanks to various clinical trials, the usefulness of different chemotherapy regimens, radiotherapy and surgical techniques with radical intent has now been demonstrated; these represent improvements in both prognosis and therapeutic approaches. Osteosarcoma patients should be evaluated in reference centres by multidisciplinary committees with extensive experience in proper management. Although numerous genetic and rheumatological diseases and risk factors have been described, the use of serological, genetic or other biomarkers has been limited in clinical practice compared to other neoplasms. This limits both the initial follow-up of these patients and screening in populations at risk. In addition, we cannot forget that the diagnosis is mainly based on the direct biopsy of the lesion and imaging tests, which illustrates the need to study new diagnostic alternatives. Therefore, the purpose of this study is to review the natural history of the disease and describe the main biomarkers, explaining their clinical uses, prognosis and limitations.

Functions and therapeutic potentials of exosomes in osteosarcoma

Osteosarcoma is a primary malignant tumor of the skeleton with the morbidity of 2.5 in 1 million. The regularly on-set is in the epiphysis of the extremities with a high possibility of early metastasis, rapid progression, and poor prognosis. The survival rate of patients with metastatic or recurrent osteosarcoma remains low, and novel diagnostic and therapeutic methods are urgently needed. Exosomes are extracellular vesicles 30-150 nm in diameter secreted by various cells that are widely present in various body fluids. Exosomes are abundant in biologically active components such as proteins, nucleic acids, and lipids. Exosomes participate in numerous physiological and pathological processes via intercellular substance exchange and signaling. This review presents the novel findings of exosomes in osteosarcoma in diagnosis, prognosis, and therapeutic aspects.

Premalignant Conditions of Bone

Development of malignancy is a multifactorial process, and there are multitude of conditions of bone that may predispose patients to malignancy. Etiologies of malignancy include benign osseous conditions, genetic predisposition, and extrinsic conditions. New-onset pain or growth in a previously stable lesion is that should concern for malignant change and should prompt a diagnostic workup for malignancy.

Guideline and Implementation of Osteosarcoma Nursing Care for Children and Adolescents

Clinical trials on pediatric oncology use therapeutic techniques with the overwhelming majority of children's cancer patients obtaining therapy via clinical investigation procedures. Medical treatment is scheduled according to a specific protocol for enrolled patients. These protocols often do not refer to nursing care. Nursing care, on the other hand, must complement the medical care specified in the medical research protocol. Safe treatment administration, assessment of treatment responses, patients' and families' education, and communication with the whole medical team are just a few of the critical nursing tasks that should be properly managed. Nursing care standards have been developed in this study to strike a good balance between the procedure for clinical research and the nursing care connected with it. These recommendations outline the nursing activities and considerations that must be made while caring for pediatric cancer patients who are engaged in a specific clinical investigation procedure. The objective of this study is to outline the procedure through which nursing care guidelines could be developed and evaluated. The goal of this study was to find out the involvement of nurses in the process of health education for osteosarcoma and family patients.

Integration of single-cell RNA sequencing and bulk RNA sequencing to reveal an immunogenic cell death-related 5-gene panel as a prognostic model for osteosarcoma

Background

Despite the comparatively low prevalence of osteosarcoma (OS) compared to other cancer types, metastatic OS has a poor overall survival rate of fewer than 30%. Accumulating data has shown the crucial functions of immunogenic cell death (ICD) in various cancers; nevertheless, the relationship between ICD and OS was not previously well understood. This research aims to determine the function of ICD in OS and construct an ICD-based prognostic panel.

Methods

Single cell RNA sequencing data from GSE162454 dataset distinguished malignant cells from normal cells in OS. The discrepancy in ICD scores and corresponding gene expression was intensively explored between malignant cells and normal cells. Using the RNA sequencing data of the TARGET-OS, GSE16091, GSE21257, and GSE39058 datasets, the molecular subtype of OS was determined by clustering seventeen ICD-related genes obtained from the literature. Differentially expressed genes (DEGs) between different molecular subtypes were identified to develop a novel ICD-associated prognostic panel.

Results

The malignant cells had a remarkable decrease in the ICD scores and corresponding gene expression compared with normal cells. A total of 212 OS patients were successfully stratified into two subtypes: C1 and C2. C1-like OS patients were characterized by better prognostic outcomes, overexpression of ICD genes, activation of the ICD pathway, high inflitration abundance of immunocytes, and low expression levels of immune checkpoint genes (ICGs); however, the reverse is true in C2-like OS patients. Utilizing the limma programme in R, the DEGs between two subtypes were determined, and a 5-gene risk panel consisting of BAMBI, TMCC2, NOX4, DKK1, and CBS was developed through LASSO-Cox regression analysis. The internal- and external-verification cohorts were employed to verify the efficacy and precision of the risk panel. The AUC values of ROC curves indicated excellent prognostic prediction values of our risk panel.

Conclusions

Overall, ICD represented a protective factor against OS, and our 5-gene risk panel serving as a biomarker could effectively evaluate the prognostic risk in patients with OS.

Pramlintide: A Novel Therapeutic Approach for Osteosarcoma through Metabolic Reprogramming

Despite aggressive combination chemotherapy and surgery, outcomes for patients with osteosarcoma have remained stagnant for more than 25 years, and numerous clinical trials have identified no new therapies. p53 deletion or mutation is found in more than 80% of osteosarcoma tumors. In p53-deficient cancers with structurally altered p63 and p73, interfering with tumor cell metabolism using Pramlintide (an FDA-approved drug for type 2 diabetes) results in tumor regression. Pramlintide response is mediated through upregulation of islet amyloid polypeptide (IAPP). Here, we showed that osteosarcoma cells have altered p63, p73, and p53, and decreased IAPP expression but have the two main IAPP receptors, CalcR and RAMP3, which inhibit glycolysis and induce apoptosis. We showed that in osteosarcoma cells with high- or mid-range glycolytic activity, Pramlintide decreased cell glycolysis, resulting in decreased proliferation and increased apoptosis in vitro. In contrast, Pramlintide had no effect in osteosarcoma cells with low glycolytic activity. Using a subcutaneous osteosarcoma mouse model, we showed that intratumoral injection of Pramlintide-induced tumor regression. Tumor sections showed increased apoptosis and a decrease in Ki-67 and HIF-1α. These data suggest that in osteosarcoma cells with altered p53, p63, and p73 and a high glycolytic function, Pramlintide therapy can modulate metabolic programming and inhibit tumor growth.

Bone mesenchymal stem cell-derived extracellular vesicles containing NORAD promote osteosarcoma by miR-30c-5p

Osteosarcoma is a bone tumor that often affects children, adolescents and young people. Non-coding RNA activated by DNA damage (NORAD) can promote the proliferation of cancer cells in multiple tumors. Thus, the current study set out to explore the role of NORAD derived from extracellular vesicles (EVs) of bone mesenchymal stem cells (BMSCs) in osteosarcoma. First, NORAD was highly expressed in osteosarcoma cells and tissues, which might be associated with the progression and metastasis of osteosarcoma. We isolated EVs from the characterized BMSCs, and found that NORAD was transferred from BMSCs to osteosarcoma cells via EVs in the co-culture system. Consequently, NORAD delivered by BMSC-derived EVs promoted the proliferation and invasion of osteosarcoma cells. Subsequently, bioinformatics analyses suggested potential binding relationship between NORAD and microRNA-30c-5p (miR-30c-5p) as well as between miR-30c-5p and Krueppel-like factor 10 (KLF10), and the results of which were further verified by dual luciferase reporter gene assay, RNA immunoprecipitation, and RNA pull-down assay. Mechanistically, NORAD acted as a sponge of miR-30c-5p and up-regulated the expression of KLF10 where miR-30-c-5p mimic declined the effect induced by NORAD on cancer cells. The osteosarcoma cells were injected into mice to develop tumor growth and metastasis models. In these two models, injection of BMSC-EVs elevated NORAD expression and KLF10 but reduced miR-30c-5p expression, whereby suppressing tumor growth and lung metastasis. To conclude, BMSC-EVs deliver NORAD to osteosarcoma cells to regulate the miR-30c-5p/KLF10 axis, thereby accelerating the progression and metastasis of osteosarcoma.

Immune Microenvironment in Osteosarcoma: Components, Therapeutic Strategies and Clinical Applications

Osteosarcoma is a primary malignant tumor that tends to threaten children and adolescents, and the 5-year event-free survival rate has not improved significantly in the past three decades, bringing grief and economic burden to patients and society. To date, the genetic background and oncogenesis mechanisms of osteosarcoma remain unclear, impeding further research. The tumor immune microenvironment has become a recent research hot spot, providing novel but valuable insight into tumor heterogeneity and multifaceted mechanisms of tumor progression and metastasis. However, the immune microenvironment in osteosarcoma has been vigorously discussed, and the landscape of immune and non-immune component infiltration has been intensively investigated. Here, we summarize the current knowledge of the classification, features, and functions of the main infiltrating cells, complement system, and exosomes in the osteosarcoma immune microenvironment. In each section, we also highlight the complex crosstalk network among them and the corresponding potential therapeutic strategies and clinical applications to deepen our understanding of osteosarcoma and provide a reference for imminent effective therapies with reduced adverse effects.

Orbital nodular fasciitis in child with biallelic germline RBL2 variant

RBL2/p130 is one of three highly conserved members of the retinoblastoma (RB) protein family. It is strongly upregulated during neuronal differentiation and brain development, and is critical for survival of post-mitotic neurons. Similar to RB1, it has been implicated as a tumor suppressor gene and has been shown to be dysregulated in various types of cancer. Recent publications describe biallelic, germline loss of function variants in RBL2 in individuals with profound developmental delay. We report a child with profound developmental delay, microcephaly, and hypotonia, who developed fulminant exophthalmos at age 6 years. Brain MRI followed by a biopsy of an intra-orbital mass revealed a mesenchymal tumor. Post-surgical histopathologic examination of the resected tumor was compatible with diagnosis of nodular fasciitis. Exome sequencing from peripheral blood identified a biallelic frameshift variant (c.901dupT) in RBL2. Notably, no malignancies were reported in previous cases with RBL2 variants. This case provides a possible association between RBL2 and orbital tumors.

Outstanding prognostic value of novel ferroptosis-related genes in chemoresistance osteosarcoma patients

Osteosarcoma (OS) is the most common bone-derived tumor, and chemoresistance is a pivotal factor in the poor prognosis of patients with OS. Ferroptosis, as an emerging modality of regulated cell death, has demonstrated potential value in tumor chemoresistance studies. Through the gene expression omnibus database in conjunction with the FerrDb database, we identified novel ferroptosis-related differentially expressed genes (DEGs) involving chemoresistance in OS patients. Subsequently, enrichment analysis, protein-protein interaction network analysis and survival analysis were performed sequentially to recognize the hub genes and ultimately to construct a predictive model. The model constructed from the TARGET database was exhibited in a nomogram and assessed by calibration curves. The prognostic value of the model and hub genes was validated separately by an independent cohort. Twenty-two ferroptosis-related DEGs were identified, including 16 up-regulated and 6 down-regulated. Among them, expressions of CBS, COCS1, EGFR, as hub genes, were significantly associated with the prognosis of OS patients and were evidenced as independent prognostic factors. An efficient prognostic model covering hub gene expressions and clinical variables was developed and validated. Combining the results of hub genes in differential analysis, the actions of hub genes in ferroptosis, and the prognostic relevance of hub genes in patients, we revealed that CBS, SOCS1 and EGFR might play essential roles in OS and its chemoresistance with potential research and clinical value.

Potential anticancer properties and mechanisms of thymoquinone in osteosarcoma and bone metastasis

Despite great advances, therapeutic approaches of osteosarcoma, the most prevalent class of preliminary pediatric bone tumors, as well as bone-related malignancies, continue to demonstrate insufficient adequacy. In recent years, a growing trend toward applying natural bioactive compounds, particularly phytochemicals, as novel agents for cancer treatment has been observed. Bioactive phytochemicals exert their anticancer features through two main ways: they induce cytotoxic effects against cancerous cells without having any detrimental impact on normal cell macromolecules such as DNA and enzymes, while at the same time combating the oncogenic signaling axis activated in tumor cells. Thymoquinone (TQ), the most abundant bioactive compound of Nigella sativa, has received considerable attention in cancer treatment owing to its distinctive properties, including apoptosis induction, cell cycle arrest, angiogenesis and metastasis inhibition, and reactive oxygen species (ROS) generation, along with inducing immune system responses and reducing side effects of traditional chemotherapeutic drugs. The present review is focused on the characteristics and mechanisms by which TQ exerts its cytotoxic effects on bone malignancies.

Pediatric solid tumors and associated cancer predisposition syndromes: Workup, management, and surveillance. A summary from the APSA Cancer Committee

BACKGROUND/PURPOSE

Cancer predisposition syndromes (CPS) are a heterogeneous group of inherited disorders that greatly increase the risk of developing malignancies. CPS are particularly relevant to pediatric surgeons since nearly 10% of cancer diagnoses are due to inherited genetic traits, and CPS often contribute to cancer development during childhood.

MATERIALS/METHODS

The English language literature was searched for manuscripts, practice guidelines, and society statements on "cancer predisposition syndromes in children". Following review of these manuscripts and cross-referencing of their bibliographies, tables were created to summarize findings of the most common CPS associated with surgically treated pediatric solid malignancies.

RESULTS

Pediatric surgeons should be aware of CPS as the identification of one of these syndromes can completely change the management of certain tumors, such as WT. The most common CPS associated with pediatric solid malignancies are outlined, with an emphasis on those most often encountered by pediatric surgeons: neuroblastoma, Wilms' tumor, hepatoblastoma, and medullary thyroid cancer. Frequently associated non-tumor manifestations of these CPS are also included as a guide to increase surgeon awareness. Screening and management guidelines are outlined, and published genetic testing and counseling guidelines are included where available.

CONCLUSION

Pediatric surgeons play an important role as surgical oncologists and are often the first point of contact for children with solid tumors. In their role of delivering a diagnosis and developing a follow-up and treatment plan as part of a multidisciplinary team, familiarity with common CPS will ensure evidence-based practices are followed, including important principles such as organ preservation and intensified surveillance plans. This review defines and summarizes the CPS associated with common childhood solid tumors encountered by the pediatric surgeon, as well as common non-cancerous disease stigmata that may help guide diagnosis.

TYPE OF STUDY

Summary paper.

LEVEL OF EVIDENCE

5.

Molecular signaling pathways as potential therapeutic targets in osteosarcoma

Among primary bone malignancies, osteosarcoma (OS) is the most common form causing morbidity and mortality in both adults and children. The interesting point about this malignancy is that nearly 10-20% of its newly diagnosed cases have developed metastasis. This adds up to the fact that the survival rate of both metastatic and non-metastatic patients of osteosarcoma hasn't changed in the past 30 years and suggests that we need to revise our therapeutic options for OS. In recent years, diverse signaling pathways have drawn the attention of the scientific community since they can be great candidates for treating complicated diseases such as cancer. In this review, we have tried to explain the pathophysiology of osteosarcoma by the help of different signaling pathways taking part in its initiation/progression and investigate how this pathway can be targeted for providing more efficient methods.

Current approaches to management of bone sarcoma in adolescent and young adult patients

Bone tumors are a group of histologically diverse diseases that occur across all ages. Two of the commonest, osteosarcoma (OS) and Ewing sarcoma (ES), are regarded as characteristic adolescent and young adult (AYA) cancers with an incidence peak in AYAs. They are curable for some but associated with unacceptably high rates of treatment failure and morbidity. The introduction of effective new therapeutics for bone sarcomas is slow, and to date, complex biology has been insufficiently characterized to allow more rapid therapeutic exploitation. This review focuses on current standards of care, recent advances that have or may soon change that standard of care and challenges to the expert clinical research community that we suggest must be met.

Long noncoding RNA ADIRF antisense RNA 1 upregulates insulin receptor substrate 1 to decrease the aggressiveness of osteosarcoma by sponging microRNA-761

An increasing number of studies have supported the critical regulatory actions of long noncoding RNAs (lncRNAs) in osteosarcoma (OS). However, the detailed roles of adipogenesis regulatory factor-antisense RNA 1 (ADIRF-AS1) in OS have not been comprehensively described. Hence, we first detected ADIRF-AS1 expression in OS and evaluated its clinical significance. Functional experiments were then performed to determine the modulatory role of ADIRF-AS1 in OS progression. ADIRF-AS1 was found to be overexpressed in OS, and the overall survival of patients with OS who had high ADIRF-AS1 levels was shorter than that of those with low levels. ADIRF-AS1 knockdown led to restricted proliferation, migration, and invasiveness of OS cells and increased apoptosis. Additionally, ADIRF-AS1 downregulation impeded tumor growth in vivo. Mechanistically, ADIRF-AS1 acted as a competitive endogenous RNA for microRNA-761 (miR-761) that siphoned miR-761 away from its target, namely insulin receptor substrate 1 (IRS1), leading to IRS1 overexpression. Rescue experiments showed that low levels of miR-761 or restoration of IRS1 could neutralize the effects of ADIRF-AS1 ablation in OS cells. In summary, ADIRF-AS1 exacerbates the oncogenicity of the OS cells by targeting the miR-761/IRS1 axis. Our findings may aid in the advancement of lncRNA-directed therapeutics for OS.

Targeting ferroptosis in osteosarcoma

Osteosarcoma (OS) is the most common primary bone tumour in children and adolescents, with high degree of malignancy and an extremely poor prognosis. Ferroptosis, a non-traditional mode of regulated cell death (RCD) characterised by iron-dependent accumulation of lipid reactive oxygen species (ROS), is closely associated with a variety of cancers. It has been demonstrated that ferroptosis can regulate OS progression and exert an essential role in the treatment of OS, which is potentially of great value. By targeting ferroptosis in OS, the present review article summarises the relevant mechanisms and therapeutic applications along with discussing current limitations and future directions, which may provide a new strategy for the treatment of OS.

Anti-cancer properties of quercetin in osteosarcoma

Osteosarcoma is a primary bone tumor. Although it is a rare disease in general, it is the most common primary bone tumor among children. Despite the significant advances made in the field of osteosarcoma treatment, the outcomes of this disease are still unfavorable. Besides, there is still no targeted therapy for osteosarcoma that can be used in clinical settings. Quercetin is a member of the phytochemical family which is used for different diseases including cardiovascular diseases, diabetes, and cancer. Its anti-cancer effects are examined in many types of cancer including breast, colon, lung, prostate, and pancreatic cancers and have shown promising results. Herein, the studies dealing with the antitumor roles of quercetin in osteosarcoma are reviewed in this article. We take a look into quercetin's ability to affect proliferation, apoptosis, invasion, and chemo-resistance of the osteosarcoma cells through regulating protein expression and signaling pathways.

Genetics of congenital solid tumors

When we discuss the genetics of tumors, we cannot fail to remember that in the second decade of the twentieth century, more precisely in 1914, Theodore Boveri defined for the first time the chromosomal bases of cancer. In the last 30 years, progresses in genetics have only confirmed Boveri's remarkable predictions made more than 80 years ago. Before the cloning of the retinoblastoma 1 (RB1) gene, the existence of a genetic component in most, if not all, solid childhood tumors were well known. The existence of familial tumor aggregations has been found much more frequently than researchers expected to find at random. Sometimes, the demonstration of this family predisposition was very difficult, because the survival of children diagnosed as having a certain tumor, up to an age at which reproduction and procreation is possible, was very rare. In recent years, advances in the diagnosis and treatment of these diseases have made it possible for these children to survive until the age when they were able to start their own families, including the ability to procreate. Four distinct groups of so-called cancer genes have been identified: oncogenes, which promote tumor cell proliferation; tumor suppressor genes, which inhibit this growth/proliferation; anti-mutational genes, with a role in deoxyribonucleic acid (DNA) stability; and micro-ribonucleic acid (miRNA) genes, with a role in the posttranscriptional process.

Identification of two immune subtypes in osteosarcoma based on immune gene sets

Osteosarcoma (OS) is a highly aggressive cancer with poor prognosis, which mainly occurs in teenagers. Recent studies have shown that tumor-infiltrating immune cells play an important role in the progression of OS. In the present study, we identified two immune subtypes of OS (referred to as high and low immune cell infiltration subtypes, respectively) based on immune-related gene sets using TARGET and GEO cohort datasets. Elevated immune scores, increased stromal scores, decreased tumor purities, and higher infiltration of CD8 + T cells and M1 macrophages were observed for the high immune cell infiltration subtype. Moreover, the high immune cell infiltration subtype was characterized by high expression of immune checkpoint molecules. Gene set enrichment analysis showed that "B cell receptor signaling pathway" and "T cell receptor signaling pathway" gene sets were enriched in the high immune cell infiltration subtype. In addition, patients in the high immune cell infiltration subtype had better prognosis than patients in the low immune cell infiltration subtype. Furthermore, differentially expressed genes were screened according to the two OS subtypes and a risk model was generated by multivariate Cox regression analysis to predict the prognosis of OS patients. These results in this study showed that OS patients could be divided into two immune subtypes and offered a novel two-gene risk signature to predict the prognosis of patients with OS.

International trends in incidence of osteosarcoma (1988-2012)

Osteosarcoma (OS) is the most common primary bone tumor in children and adolescents. The etiology of OS is largely unknown but may be informed by comparisons of incidence and trends between geographic regions. Using the Cancer Incidence in Five Continents (CI5) data from 1988 to 2012, we present OS age-standardized incidence rates (ASRs; cases/million) and average annual percent change (AAPC) and 95% confidence interval (CI) by geographic region among the age groups 0-9, 10-19, 20-29, 30-59, 60-79, 0-79. Among the 10-19 age group, we also used the most recent data (2008-2012) to present the ASRs for each country. We observed little variation in OS incidence between geographic regions in 2008-2012 across all age groups. Overall, the ASR for 0-79 ranged from 2 cases per million in Southern Asia to 4.2 in Sub-Saharan Africa. A bimodal distribution in incidence was observed with peaks in the 10-19 and 60-79 age groups across all regions over time. Overall, OS incidence was relatively stable across 1988-2012 with the only statistically significant increases in the 0-79 age group observed in Eastern Asia (AAPC: 1.8; 95% CI: 0.6, 1.9) and Sub-Saharan Africa (AAPC: 3.1; 95% CI: 0.5, 5.8). The small variation in incidence between regions and the stability in incidence over time suggests that OS carcinogenesis is not influenced by environmental or time-varying exposures.

Osteosarcoma in One of Identical Twins: Three Cases Report and a Literature Review

Background

Osteosarcoma (OS) is the most common primary malignant bone tumor occurring mainly in children and young adults. OS is usually seen in sporadic cases, and it is an extremely rare phenomenon in blood relatives, particularly among identical twins.

Case Presentation

The present study reports three cases of OS occurring in only one of identical twins. The first case is a high‐grade OS in the left proximal tibia of a 16‐year‐old girl, treated with neo‐adjuvant chemotherapy, en bloc resection, and reconstruction with a modular knee tumor prosthesis. The second one is a high‐grade OS of the left proximal tibia of a 6‐year‐old girl. The patient was treated with neo‐adjuvant chemotherapy, en bloc resection, and reconstruction with inactived autograft. The third one is a conventional OS of the right proximal tibia of a 20‐year‐old woman. She was treated with neo‐adjuvant chemotherapy, en bloc resection, and reconstruction with a custom‐made prosthesis.

Conclusions

The occurrence of OS in one of identical twins is a relatively rare event but may present the best opportunity to understand the genetic mechanisms underlying the tumorigenesis and progression of this disease in humans. A longer follow‐up period and regular imaging evaluation are needed to confirm whether the identical twin of these patients will suffer OS in the future.

Second Osteosarcoma in a 16-Year-old Woman Diagnosed With Rothmund-Thomson Syndrome

Rothmund-Thomson syndrome (RTS) is an autosomal recessive disorder associated with an increased predisposition to osteosarcoma (OS) when it is caused by concrete mutations in the RECQL4 gene. Most OSs arise sporadically, but it can also be the first manifestation of a cancer predisposition syndrome as Rothmund Thompson. The early onset, multifocality and metachronism, and a family history of the disease, may suggest a tumor predisposition syndrome. We present the case of a patient with a polymalformative syndrome, who, at 6 years of age, was diagnosed with OS in the right femur. This led to the diagnosis of a RTS type 2. She was cured and surveillance showed no sign of disease. Ten years later, the patient developed a second OS in the contralateral femur. Fortunately, she is in complete remission again after treatment. We describe our patient treatment and recommend a possible screening-surveillance for RTS type II patients.

BMPR2 expression level is correlated with low immune infiltration and predicts metastasis and poor survival in osteosarcoma

Osteosarcoma is the most common malignant bone tumor in adolescents and young adults, and identifying biomarkers for prognosis and therapy is necessary. Bone morphogenetic protein receptor 2 (BMPR2) is involved in various cellular functions, including cell adhesion, proliferation and invasion, inflammation, apoptosis and metastatic spread. However, the correlation between BMPR2 expression levels and prognosis and tumor-infiltrating immune cells in osteosarcoma is not well understood. In the present study, the expression level of BMPR2 was investigated using the Oncomine and R2 databases. The association between the expression level of BMPR2 and the clinical prognosis of patients with cancer was analyzed using the R2 database. The relationship between the expression level of BMPR2 and immune cell infiltration in the stroma of osteosarcoma was assessed using the Tumor Immune Estimation Resource (TIMER) and CIBERSORT. The correlations between BMPR2 expression level and infiltrated immune cell gene marker sets in osteosarcoma were validated in the TIMER and R2 databases. Analysis of a cohort of patients with osteosarcoma revealed that BMPR2 expression was significantly higher in osteosarcoma compared with in normal tissue and was correlated with poor prognosis. M0 macrophages, M2 macrophages, resting mast, γ δ T and CD8+ T cells were the top five immune cells with the highest degrees of infiltration in osteosarcoma. In addition, BMPR2 expression level showed a significant negative correlation with the gene markers of CD8+ T cells, monocytes and M2 macrophages. Low levels of infiltrating CD8+ T cells, monocytes or M2 macrophages in osteosarcoma was significantly associated with poor survival. These data suggested that CD8+ T cells, monocytes and M2 macrophages play significant roles in the establishment of the immune microenvironment of osteosarcoma. High BMPR2 expression was associated with poor prognosis and low infiltration of CD8+ T cells, monocytes and M2 macrophages in osteosarcoma. Hence, BMPR2 can be considered a biomarker of the immune infiltration, metastasis and prognosis of osteosarcoma.

Potential Antimetastatic Effect of Timosaponin AIII against Human Osteosarcoma Cells through Regulating the Integrin/FAK/Cofilin Axis

Timosaponin AIII (TSAIII) is a steroidal saponin which demonstrates anti-tumour activities. However, the effect of TSAIII on human osteosarcoma cells remains largely unknown. In this study, we demonstrated that TSAIII exerted a significant inhibitory effect on the distribution of cytoskeletal F-actin and cytoskeletal-related proteins, which contributed to the suppression of cell migration and invasion, without inhibiting cell growth or apoptosis. In the synergistic inhibitory analysis, cotreatment of TSAIII with αVβ3 integrin inhibitor [Cyclo(RGDyK)] or focal adhesion kinase (FAK) inhibitor (PF-573228) exerted greater synergistic inhibitory effects on the expression of Intergin αVβ3/FAK/cofilin axis, thus inhibiting the migration and invasion capacities of human osteosarcoma cells. TSAIII was demonstrated to significantly inhibit the pulmonary metastasis formation of human osteosarcoma cells in vivo in metastasis animal models. These findings reveal the inhibitory effects of TSAIII on the metastasis progression of human osteosarcoma cells and the regulation of integrin-αVβ3-FAK-Src and TESK1/p-cofilin mediated cytoskeletal F-actin pathway. Therefore, TSAIII might represent a novel strategy for the auxiliary treatment of human osteosarcoma cells.

Prevalence of germline pathogenic variants in 22 cancer susceptibility genes in Swedish pediatric cancer patients

Up to 10% of pediatric cancer patients harbor pathogenic germline variants in one or more cancer susceptibility genes. A recent study from the US reported pathogenic variants in 22 out of 60 analyzed autosomal dominant cancer susceptibility genes, implicating 8.5% of pediatric cancer patients. Here we aimed to assess the prevalence of germline pathogenic variants in these 22 genes in a population-based Swedish cohort and to compare the results to those described in other populations. We found pathogenic variants in 10 of the 22 genes covering 3.8% of these patients. The prevalence of TP53 mutations was significantly lower than described in previous studies, which can largely be attributed to differences in tumor diagnosis distributions across the three cohorts. Matched family history for relatives allowed assessment of familial cancer incidence, however, no significant difference in cancer incidence was found in families of children carrying pathogenic variants compared to those who did not.

Translational cell biology of highly malignant osteosarcoma

Highly malignant osteosarcoma (HMO) is the most frequent malignant bone tumor preferentially occurring in adolescents and children with a second more flat peak in patients over the age of 60. The younger patients benefit from combined neoadjuvant chemotherapy with 65-70% 5-year survival rate. In patients with metastatic HMO the 5-year survival rate is consistently poor with approximately 30%. In the last several years strategies for target therapies have been developed by using next generation sequencing (NGS) for defining targetable molecular factors. However, it has so far been challenging to establish an effective target therapy for so-called 'orphan tumors' without recognizable driver mutations, including HMO. The molecular genetic studies using NGS have shown that HMOs are genomically unstable tumors with highly complex chaotic karyotypes. Before the background of this genetic complexity more investigations should be performed in the future for defining targetable biological factors. As the prognosis could not be improved for 40 years one may expect improvements for patients only by gaining a deeper understanding of the cell and molecular biology of HMO. The cell of origin of HMO is being clarified now. The majority of studies indicate that an osteoblastic progenitor cell is probably the cell of origin of HMO and not an undifferentiated mesenchymal stem cell. This means that the established histopathological definition of HMO through verification of osteoid production by the osteoblastic cells is well justified and will probably be the cornerstone for a precise differential diagnosis of HMO also in the years to come.

Identification and Verification of Immune-Related Gene Prognostic Signature Based on ssGSEA for Osteosarcoma

Osteosarcoma is the most common malignant bone tumor in children and adolescence. Multiple immune-related genes have been reported in different cancers. The aim is to identify an immune-related gene signature for the prospective evaluation of prognosis for osteosarcoma patients. In this study, we evaluated the infiltration of immune cells in 101 osteosarcoma patients downloaded from TARGET using the ssGSEA to the RNA-sequencing of these patients, thus, high immune cell infiltration cluster, middle immune cell infiltration cluster and low immune cell infiltration cluster were generated. On the foundation of high immune cell infiltration cluster vs. low immune cell infiltration cluster and normal vs. osteosarcoma, we found 108 common differentially expressed genes which were sequentially submitted to univariate Cox and LASSO regression analysis. Furthermore, GSEA indicated some pathways with notable enrichment in the high- and low-immune cell infiltration cluster that may be helpful in understanding the potential mechanisms. Finally, we identified seven immune-related genes as prognostic signature for osteosarcoma. Kaplan-Meier analysis, ROC curve, univariate and multivariate Cox regression further confirmed that the seven immune-related genes signature was an innovative and significant prognostic factor independent of clinical features. These results of this study offer a means to predict the prognosis and survival of osteosarcoma patients with uncovered seven-gene signature as potential biomarkers.

Modeling of osteosarcoma with induced pluripotent stem cells

Osteosarcoma is the most common type of bone cancer. Osteosarcoma is commonly associated with TP53 inactivation (around 95% of cases) and RB1 inactivation (around 28% of cases). With the discovery of reprogramming factors to induce pluripotency even in terminally differentiated cells, induced pluripotent stem cells (iPSCs) have emerged as a promising disease model. iPSC-based disease modeling uniquely recapitulates disease phenotypes and can support discoveries into disease etiology and is used extensively today to study a variety of diseases, including cancers. This paper focuses on iPSC-based modeling of Li-Fraumeni syndrome (LFS), an autosomal dominant disorder commonly associated with TP53 mutation and high osteosarcoma incidence. As iPSCs are increasingly utilized as a platform for cancer modeling, the experimental approaches that we discuss here may serve as a guide for future studies.