Objectives: Osteosarcoma is a malignant bone tumor with poor outcomes affecting the adolescents and elderly. In this study, we comprehensively assessed the metabolic characteristics of osteosarcoma patients and constructed a hexosamine biosynthesis pathway (HBP)-based risk score model to predict the prognosis and tumor immune infiltration in patients with osteosarcoma.Methods: Gene expression matrices of osteosarcoma were downloaded from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) and Gene Expression Omnibus (GEO) databases. GSVA and univariate Cox regression analysis were performed to screen the metabolic features associated with prognoses. LASSO regression analysis was conducted to construct the metabolism-related risk model. Differentially expressed genes (DEGs) were identified and enrichment analysis was performed based on the risk model. CIBERSORT and ESTIMATE algorithms were executed to evaluate the characteristics of tumor immune infiltration. Comparative analyses for immune checkpoints were performed and the Tumor Immune Dysfunction and Exclusion (TIDE) algorithm was used to predict immunotherapeutic response. Finally, hub genes with good prognostic value were comprehensive analyzed including drug sensitivity screening and immunohistochemistry (IHC) experiments.Results: Through GSVA and survival analysis, the HBP pathway was identified as the significant prognostic related metabolism feature. Five genes in the HBP pathway including GPI, PGM3, UAP1, OGT and MGEA5 were used to construct the HBP-related risk model. Subsequent DEGs and enrichment analyses showed a strong correlation with immunity. Further, CIBERSORT and ESTIMATE algorithms showed differential immune infiltration characteristics correlated with the HBP-related risk model. TIDE algorithms and immune checkpoint analyses suggested poor immunotherapeutic responses with low expression of immune checkpoints in the high-risk group. Further analysis revealed that the UAP1 gene can predict metastasis. IHC experiments suggested that UAP1 expression correlated significantly with the prognosis and metastasis of osteosarcoma patients. When screening for drug sensitivity, high UAP1 expression was suggestive of great sensitivity to antineoplastic drugs including cobimetinib and selumetinib.Conclusion: We constructed an HBP-related gene signature containing five key genes (GPI, PGM3, UAP1, OGT, MGEA5) which showed a remarkable prognostic value for predicting prognosis and can guide immunotherapy and targeted therapy for osteosarcoma.

Objective: Treating pediatric osteosarcoma in long bones is challenging due to skeletal immaturity, which restricts the generalizability of insights derived from adult patients. Are there disparities in outcomes? How should surgical protocols be tailored for children of varying ages? What are the specific postoperative complications? A large single-center retrospective cohort study of 345 patients under 14 years old with lower-limb osteosarcoma treated in our department since 2000 was conducted to address these inquiries. Methods: A retrospective analysis of 345 pediatric patients with lower-limb osteosarcoma admitted to our department between 2000 and 2019 was conducted. Clinical and functional outcomes were compared based on age groups, surgical methods, type of prosthesis, and primary tumor location. Patients were divided into the low-age group (≤10 y old) and the high-age group (>10 y old). Overall survival rate (OS), progressionfree survival rate (PFS), and prosthesis survival rate were assessed using Kaplan–Meier curves, nonparametric survival analysis (log-rank test), and Univariate cox regression were used for comparison. The incidence of complications, local relapse rate (LRR), metastasis rate, final limb-salvage, and amputation rate, and Musculoskeletal Tumor Society (MSTS) score of different independent groups were further evaluated using χ ² test or Fisher’s exact test, and t-test was employed to evaluate the measurement data. Results: The average age of the patients was 11.10±2.32 years ranging from 4 to 14 y, with an average follow-up duration of 48.17 months. The 5, 10, and 15-year OS rates were 50.3%, 43.8%, and 37.9%, respectively. The progression-free survival rate was 44.8% at 5 years and 41.1% at 10 years. The final limb salvage rate was 61.45%, while the final amputation rate was 38.55%. The low-age group had a higher amputation rate compared with the high-age group (48.00% vs. 33.18%, P=0.009). The overall LRR was 9.28%, and the incidence of metastasis was 28.99%. The LRR of the limb-salvage group was higher than the amputation group (P=0.004). The low-age group experienced more prosthesis-related complications than the high-age group (P=0.001). The most common prosthesis-related complication in the low-age group was soft-tissue failure, while the periprosthetic infection was most frequent in the high-age group. The high-age group had a higher cumulative prosthesis survival compared with the low-age group (P=0.0097). Modular prosthesis showed better MSTS scores and higher cumulative prosthetic survival than expandable prosthesis in pediatric patients (P<0.05). Conclusion: Limb preservation in pediatric patients becomes increasingly efficacious with advancing age, while consideration of amputation is warranted for younger patients. The prevailing postoperative complications associated with prosthesis encompass soft tissue failure and periprosthetic infection. Younger patients diagnosed with lower limb osteosarcoma exhibit a heightened amputation rate and a greater incidence of prosthesis-related complications.

Background: Osteosarcoma is the most prevalent primary malignant bone tumor affecting pediatric and adolescent individuals. However, despite the passage of three decades, there has been no notable enhancement in the overall survival rate of patients with osteosarcoma. In recent years, CD155 has been reported to exhibit abnormal amplification in a range of tumors, yet the precise underlying mechanism remains elusive. The objective of this study is to investigate the role of CD155 in osteosarcoma, and to identify drugs that specifically target this molecule, thereby offering a novel direction for the treatment of osteosarcoma. Methods: The prognosis of patients with osteosarcoma with high and low expression of CD155 was verified by immunohistochemistry. CCK-8 and colony formation assays were used to detect cell proliferation and drug resistance. Transwell experiments were used to detect cell migration and invasion. The sphere formation experiment was used to evaluate the stemness of tumor cells. Additionally, in vivo animal models were utilized to assess the functional role of CD155 in a biological context. RNA-seq and co-immunoprecipitation methods were used to search for downstream target molecules and signaling pathways of CD155. Finally, virtual screening was used to find drugs targeting CD155. Results: In this study, we have established the significant amplification of CD155 in osteosarcoma. Utilizing a comprehensive array of experimental methods, including CCK-8 assay, colony formation assay, Transwell assay, and in vivo animal models, we unequivocally demonstrate that CD155 significantly potentiates the malignancy of osteosarcoma both in vitro and in vivo. Additionally, our findings reveal that CD155 promotes osteosarcoma stemness by modulating the Wnt/β-catenin signaling pathway. Advanced molecular techniques, such as RNA sequencing and co-immunoprecipitation, have been instrumental in elucidating the mechanism of CD155 in activating the Wnt/β-catenin pathway via the SRC/AKT/GSK3β signaling axis, thereby enhancing the stem-cell-like properties of osteosarcoma cells. To explore targeted therapeutic options, we conducted virtual screening and identified troxerutin as a promising CD155 inhibitor. Conclusions: Our findings reveal that troxerutin effectively inhibits CD155, attenuates the SRC/AKT/GSK3β signaling cascade, diminishes the nuclear localization of β-catenin, and consequently mitigates osteosarcoma stemness. These discoveries position troxerutin as a promising candidate for targeted osteosarcoma therapy.

Background: At present, amputation was widely adopted for young patients when limb salvage was deemed risky with several surgical strategy such as rotationplasty. However, leg length discrepancies and unfavorable cosmetic results were indispensable complication of this strategy. The purpose of this study was to propose a novel reconstruction strategy and evaluate the early clinical and functional outcomes of the strategy. Methods: Plastic lengthening amputation (PLA) has been developed by lengthening the stump to preserve one additional distal joint for fixing the artificial limb well. The surgical technique and postoperative management were documented, and the functional outcomes were compared with those of traditional amputation (TA). Six pairs of patients matched for age, sex, location, pathological type, and final prosthesis underwent individually designed plastic lengthening amputation with vascularized autografts or traditional amputation between January 2005 and December 2007. All patients were followed, and the locomotor index and the musculoskeletal tumor society score (MSTS) were used to describe and quantitatively grade limb functional outcomes after amputation. The complications and functional outcomes of the patients taken two kinds of procedures were compared. Results: Twelve patients with osteosarcoma or Ewing’s sarcoma of either the femur or tibia were included in the study. Six patients underwent plastic lengthening amputations, three of whom also underwent vascular anastomosis. Patients were followed for an average of 48.17 months; bone healing required an average of 3.3 months. No local recurrence was found. The average postoperative locomotor index functional score of the affected limb was 32.67 ± 5.89 in the plastic lengthening amputation group while was 19.50 ± 7.87 in the traditional amputation group. The MSTS functional scores were 22.67 ± 1.33 and 24.17 ± 1.45 at 6 and 12 months for patients in PLA group while 17.00 ± 1.549 and 17.83 ± 1.64 at 6 and 12 months for patients in TA group. Conclusions: Plastic lengthening amputations with vascularized autografts could preserve the knee joint to improve the function of the amputated limb in selected bone sarcoma patients.

This study aimed to summarize the survival and complication profiles of the compress® endoprosthesis (CPS) through a systematic review and meta-analysis. Online databases (PubMed, EMBASE and Web of Science) were searched from inception to November 2023. Trials were included that involved the use of CPS for endoprosthetic replacement in patients with massive segmental bone defects. Patients’ clinical characteristics and demographic data were extracted using a standardized form. The methodological quality of included 13 non-comparative studies was assessed on basis of the Methodological Index for Non-Randomized Studies (MINORS). All the available Kaplan-Meier curves in the included studies were digitized and combined using Engauge-Digitizer software and the R Project for Statistical Computing. The meta-analysis of thirteen included studies indicated: the all-cause failure rates of CPS were 26.3 % after surgery, in which the occurrence rates of aseptic loosening were 5.8 %. And the incidences of other complications were as follows: soft tissue failure (1.8 %), structure failure (8.2 %), infection (9.5 %), tumor progression (1.1 %). The 1-, 4-, and 8-year overall survival rates for all-cause failure with 95 % CI were 89 % (86 %-92 %), 75 % (71 %-79 %) and 65 % (60 %-70 %), respectively. The estimated mean survival time of all-cause failure was 145 months (95 % CI, 127–148 months), and the estimated median survival time of all-cause failure was 187 months (95 % CI, 135–198 months). The 1-, 4-, and 8-year overall survival rates of aseptic loosening with 95 % CI were 96 % (94 %-98 %), 91 % (87 %-95 %) and 88 % (83 %-93 %), respectively. The estimated mean survival time of aseptic loosening was 148 months (95 % CI, 137–153 months). CPS’s innovative spring system promotes bone ingrowth by providing immediate and high-compression fixation, thereby reducing the risk of aseptic loosening caused by stress shielding and particle-induced osteolysis. CPS requires less residual bone mass for reconstructing massive segmental bone defects and facilitates easier revision due to its non-cemented fixation. In addition, the survival rate, estimated mean survival time, and complication rates of CPS are not inferior to those of common endoprosthesis.

Background: To review and study 14 cases of phosphaturic mesenchymal tumor (PMT) patients, integrating previous literature to expand understanding of this disease, improve diagnosis rates, and enhance treatment efficacy. Methods: This study included 14 patients with PMT who were treated and pathologically confirmed at our bone tumor center between December 2016 and September 2023. Clinical data, including imaging, pathological findings, and laboratory results, were collected and analyzed. All patients underwent preoperative PET/CT scanning, followed by surgery, and were monitored during an average postoperative follow-up period of 28.86 ± 21.72 months. The surgical procedures included tumor resection, curettage, and ablation. Results: The study cohort comprised 10 males and 4 females. Tumor locations included the femur (6 cases), tibia (3 cases), humerus (1 case), fibula (2 cases), ilium (1 case), and the posterior edge of the right deltoid muscle (1 case). The average tumor size was 3.6 ± 1.3 cm. Most patients exhibited systemic osteomalacia, with 11 patients experiencing multiple rib fractures and an average preoperative disease duration of 29.04 ± 22.83 months. All patients demonstrated varying degrees of hypophosphatemia and elevated alkaline phosphatase levels, with PET/CT scans revealing increased FDG/DOTANOC uptake in the lesions. Postoperative follow-up indicated that patients who underwent tumor resection showed superior improvements in blood phosphorus levels and bone density compared to those who underwent curettage or ablation. The Musculoskeletal Tumor Society (MSTS) scores of all patients significantly improved postoperatively, increasing from a preoperative mean of 20.22 ± 3.44 to a postoperative mean of 28.38 ± 1.05 ( P < 0.05). Conclusion: PMT is a rare and challenging mesenchymal tumor to diagnose due to its nonspecific symptoms and low incidence. The combination of DOTANOC-PET/CT imaging and postoperative pathological examination provides a reliable diagnostic approach. Among the surgical options, tumor resection has demonstrated superior efficacy in improving both biochemical markers and clinical outcomes, making it the preferred treatment method over tumor curettage or ablation. Level of evidence: Level IV, therapeutic study.