Age-dependent molecular variations in osteosarcoma: implications for precision oncology across pediatric, adolescent, and adult patients.

Background: Osteosarcoma is a leading subtype of bone tumor affecting adolescents and adults. Comparative molecular characterization among different age groups, especially in pediatric, adolescents and adults, is scarce. Methods: We collected samples from 194 osteosarcoma patients, encompassing pediatric, adolescent, and adult cohorts. Genomic analyses were conducted to reveal prevalent mutations and compare molecular features in pediatric, adolescent, and adult patients. Results: Samples from 194 osteosarcoma patients across pediatric to adult ages were analyzed, revealing key mutations such as TP53, FLCN, NCOR1, and others. Children and adolescents showed more gene amplifications and HRD mutations, while adults had a greater Tumor Mutational Burden (TMB). Mutations in those over 15 were mainly in cell cycle and PI3K/mTOR pathways, while under 15s had more in cell cycle and angiogenesis with higher VEGFA, CCND3, TFEB mutations. CNV patterns varied with age: VEGFA and XPO5 amplifications more in under 25s, and CDKN2A/B deletions in over 25s. Genetic alterations in genes like MCL1 and MYC were associated with poor prognosis, with VEGFA mutations also indicating worse outcomes. 58% of patients had actionable mutations, suggesting opportunities for targeted therapies. Age-specific patterns were observed, with Multi-TKI mutations more common in younger patients and CDK4/6 inhibitor mutations in adults, highlighting the need for personalized treatment approaches in osteosarcoma. In a small group of patients with VEGFR amplification, postoperative treatment with multi-kinase inhibitors resulted in a PR in 3 of 13 cases, especially in patients under 15. A significant case involved a 13-year-old with a notable tumor size reduction achieving PR, even with other genetic alterations present in some patients with PD. Conclusion: This study delineates the molecular differences among pediatric, adolescent, and adult osteosarcoma patients at the genomic level, emphasizing the necessity for precision diagnostics and treatment strategies, and may offer novel prognostic biomarkers for patients with osteosarcoma. These findings provide a significant scientific foundation for the development of individualized treatment approaches tailored to patients of different age groups.

Comparison of oncological and functional outcomes in Lower-limb osteosarcoma pediatric patient : A large single-center retrospective cohort study.

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), Progression-Free Survival rate (PFS), and prosthesis survival rate were assessed using Kaplan-Meier curves, Non-parametric 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 χ2 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 to 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 to 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.

Prognostic and predictive value of super-enhancer-derived signatures for survival and lung metastasis in osteosarcoma.

BACKGROUND: Risk stratification and personalized care are crucial in managing osteosarcoma due to its complexity and heterogeneity. However, current prognostic prediction using clinical variables has limited accuracy. Thus, this study aimed to explore potential molecular biomarkers to improve prognostic assessment. METHODS: High-throughput inhibitor screening of 150 compounds with broad targeting properties was performed and indicated a direction towards super-enhancers (SEs). Bulk RNA-seq, scRNA-seq, and immunohistochemistry (IHC) were used to investigate SE-associated gene expression profiles in osteosarcoma cells and patient tissue specimens. Data of 212 osteosarcoma patients who received standard treatment were collected and randomized into training and validation groups for retrospective analysis. Prognostic signatures and nomograms for overall survival (OS) and lung metastasis-free survival (LMFS) were developed using Cox regression analyses. The discriminatory power, calibration, and clinical value of nomograms were evaluated. RESULTS: High-throughput inhibitor screening showed that SEs significantly contribute to the oncogenic transcriptional output in osteosarcoma. Based on this finding, focus was given to 10 SE-associated genes with distinct characteristics and potential oncogenic function. With multi-omics approaches, the hyperexpression of these genes was observed in tumor cell subclusters of patient specimens, which were consistently correlated with poor outcomes and rapid metastasis, and the majority of these identified SE-associated genes were confirmed as independent risk factors for poor outcomes. Two molecular signatures were then developed to predict survival and occurrence of lung metastasis: the SE-derived OS-signature (comprising LACTB, CEP55, SRSF3, TCF7L2, and FOXP1) and the SE-derived LMFS-signature (comprising SRSF3, TCF7L2, FOXP1, and APOLD1). Both signatures significantly improved prognostic accuracy beyond conventional clinical factors. CONCLUSIONS: Oncogenic transcription driven by SEs exhibit strong associations with osteosarcoma outcomes. The SE-derived signatures developed in this study hold promise as prognostic biomarkers for predicting OS and LMFS in patients undergoing standard treatments. Integrative prognostic models that combine conventional clinical factors with these SE-derived signatures demonstrate substantially improved accuracy, and have the potential to facilitate patient counseling and individualized management.

Augmenting L3MBTL2-induced condensates suppresses tumor growth in osteosarcoma.

Osteosarcoma is a highly aggressive cancer and lacks effective therapeutic targets. We found that L3MBTL2 acts as a tumor suppressor by transcriptionally repressing IFIT2 in osteosarcoma. L3MBTL2 recruits the components of Polycomb repressive complex 1.6 to form condensates via both Pho-binding pockets and polybasic regions within carboxyl-terminal intrinsically disordered regions; the L3MBTL2-induced condensates are required for its tumor suppression. Multi-monoubiquitination of L3MBTL2 by UBE2O results in its proteasomal degradation, and the UBE2O/L3MBTL2 axis was crucial for osteosarcoma growth. There is a reverse correlation between L3MBTL2 and UBE2O in osteosarcoma tissues, and higher UBE2O and lower L3MBTL2 are associated with poorer prognosis in osteosarcoma. Pharmacological blockage of UBE2O by arsenic trioxide can enhance L3MBTL2-induced condensates and consequently suppress osteosarcoma growth. Our findings unveil a crucial biological function of L3MBTL2-induced condensates in mediating tumor suppression, proposing the UBE2O-L3MBTL2 axis as a potential cancer therapeutic target in osteosarcoma.

Therapeutic Copolymer from Salicylic Acid and l-Phenylalanine as a Nanosized Drug Carrier for Orthotopic Breast Cancer with Lung Metastasis.

Nanoparticle (NP)-mediated drug delivery systems are promising for treating various diseases. However, clinical translation has been delayed by a variety of limitations, such as weak drug loading, nonspecific drug leakage, lack of bioactivity, and short blood circulation. These issues are in part due to the unsatisfactory function of biomaterials for nanocarriers. In addition, the synthesis procedures of drug carrier materials, especially polymers, were usually complicated and led to high cost. In this report, a bioactive copolymer of hydroxy acid and amino acid, poly(salicylic acid-co-phenylalanine) (PSP), was developed for the first time via a one-step rapid and facile synthesis strategy. The PSP could self-assemble into NPs (PSP-NPs) to co-load relatively hydrophilic sphingosine kinase 1 inhibitor (PF543 in HCl salt format) and highly hydrophobic paclitaxel (PTX) to form PF543/PTX@PSP-NPs with efficient dual drug loading. Encouragingly, PF543/PTX@PSP-NPs showed long blood circulation, good stability, and high tumor accumulation, leading to significantly enhanced therapeutic effects on breast cancer. Furthermore, PF543/PTX@PSP-NPs could additionally suppress the lung metastasis of breast cancer, and more importantly, the PSP-NPs themselves as therapeutic nanocarriers also showed an anti-breast cancer effect. With these combined advantages, this new polymer and corresponding NPs will provide valuable insights into the development of new functional polymers and nanomedicines for important diseases.

Preoperative denosumab treatment in patients with giant cell bone tumors in limbs: A retrospective study using propensity score matching.

BACKGROUND AND OBJECTIVES: Denosumab is recommended for advanced giant cell tumor of bone (GCTB) that is unresectable or resectable with unacceptable morbidity. But the effect of preoperative denosumab treatment on the local control GCTB remains controversial. METHODS: We conducted a study of 49 patients with GCTB in the limbs treated with denosumab before surgery and 125 patients without in our hospital from 2010 to 2017. Propensity-score matching (PSM) at a 1:1 ratio between the denosumab and control groups was performed to minimize possible selection bias, and compared the recurrence rate, limb function, and surgical degradation between the two groups. RESULTS: The 3-year recurrence rates in the denosumab group and the control group were 20.4% and 22.9% after PSM, respectively (p = 0.702). In the denosumab group, 75.5% (n = 37/49) of patients experienced surgical downgrading. Limb joint preservation rates were 92.1% (35) for 38 patients treated with denosumab and 60.2% (71) for 118 control subjects. (p ≺ 0.001). Postoperative MSTS were higher in patients in the denosumab group than in the control group (24.1 vs. 22.6, p = 0.034). CONCLUSIONS: Preoperative denosumab treatment did not result in an increased risk of local recurrence of GCTB. Patients with advanced GCTB may benefit from preoperative denosumab treatment for surgical downgrading and the preservation of the joint.

Erratum: Author correction to "The FAPα-activated prodrug Z-GP-DAVLBH inhibits the growth and pulmonary metastasis of osteosarcoma cells by suppressing the AXL pathway" [Acta Pharm Sin B 12 (2022) 1288-1304].

[This corrects the article DOI: 10.1016/j.apsb.2021.08.015.].

Surgical Strategy and Application of Robotic-Assisted Benign Sacral Neurogenic Tumor Resection.

BACKGROUND: Robotic surgery may be advantageous in neurogenic sacral tumor resection but only a few studies reported robotic-assisted neurogenic sacral tumor resection. OBJECTIVE: To propose a new surgical strategy for robotic-assisted benign sacral neurogenic tumor resection and introduce the ultrasonic osteotomy surgical system in robotic surgery. METHODS: Twelve patients who had robotic-assisted primary benign sacral neurogenic tumor resection between May 2015 and March 2021 were included. Our surgical strategy divides tumors into 4 types. Type I: Presacral tumors with diameter <10 cm. Type II: Narrow-base tumors involving the sacrum with diameter <10 cm. Type III: Broad-base tumors involving the sacrum with diameter <10 cm. Type IV: Tumors involving sacral nerve roots ≥2 levels and/or with diameter ≥10 cm. RESULTS: Five type I, 5 type II, and 1 type III patients underwent tumor resection via an anterior approach, and 1 type IV patient via a combined approach. The median operation time, blood loss, and postoperative hospital stay of type I and II were much less than those of type IV. The ultrasonic osteotomy surgical system facilitated osteotomy in 2 type II and 1 type III patients. Eleven patients had total resections, and 1 type III patient had a partial resection. During the follow-up period of 7.9 to 70.9 months (median: 28.5 months), no local recurrences or deaths were noted. CONCLUSION: With the largest single-center series to our knowledge, this surgical strategy helped to guide robotic-assisted benign sacral neurogenic tumor resection. The ultrasonic osteotomy surgical system was effective for type II and III.

Autologous menisci-cruciate ligament composite as a flap for soft tissue reconstruction following malignant bone tumor resection around the knee.

BACKGROUND: Despite significant improvements in oncological treatment, the management of soft tissue defects following malignant tumor resection remains challenging. We investigated whether autologous menisci and cruciate ligament, which are traditionally discarded, can be recycled as a supplemental flap in repairing soft tissue defects following malignant bone tumor resection and endoprosthetic reconstruction around the knee. METHODS: Four knee specimens were dissected to provide a basis for the design of the menisci-cruciate ligament composite. Then, 40 patients with bone malignancies around the knee were enrolled and underwent reconstruction with free or vascularized composite following malignant tumor resection. The clinical, radiographic, and functional outcomes of this technique were evaluated in >1-year follow-up in each patient and compared with 87 patients who suffered from bone malignancies around the knee and were treated by limb salvage but without composite at our center over the same period. During the follow-up, a composite from one patient who underwent secondary amputation was retrieved and examined for in vivo remodeling. RESULTS: Fourteen patients were treated with vascularized composite transfer (10 distal femurs and 4 proximal tibias) and 26 patients with free composite transfer (19 distal femurs and 7 proximal tibias). The composite can be used to cover the area of soft tissue defect from 22 to 48.38 cm2 (34.67 ± 6.48 cm2 ). With contrast-enhanced ultrasound, peripheral rim healing and dotted blood flow signal at the side of anastomosis were detected on a patient 16 months after free composite transfer. Gross macroscopic remodeling and histopathologic analysis of a retrieved composite also indicated good healing with surrounding tissues and living cells in the composite. The complications and oncologic outcomes were comparable between study and control cohorts, but better Musculoskeletal Tumor Society (MSTS) score for patients reconstructed with composite (26.68 vs. 25.66, p  = 0.004). Of note, MSTS score was higher for patients reconstructed with composite at distal femur subdivision compared with the same subdivision in the control cohort (26.97 vs. 25.90, p  = 0.009). No statically significant difference was noted in complications, oncologic, and functional outcomes for patients reconstructed with free or vascularized composite. CONCLUSION: Autogenous menisci-cruciate ligament composite is an alternative option for soft tissue reconstruction. Either vascularized or free composite can be applied, depending on the size and localization of the defect.

Mediating effect assessment of ifosfamide on limb salvage rate in osteosarcoma: A study from a single center in China.

Osteosarcoma is one of the most prevalent primary bone malignancies in children and adolescents. Surgery and chemotherapy are the standard treatment methods of osteosarcoma. Methotrexate, adriamycin, and cisplatin, and methotrexate, adriamycin, cisplatin, and ifosfamide regimens are both first-line neoadjuvant chemotherapy regimens for osteosarcoma. Moreover, the use of ifosfamide is highly controversial. Most studies of ifosfamide focused on the overall survival rate and event-free survival rate; few studies concentrated on surgical options. We conducted this retrospective study to compare the baseline characteristic of amputation and limb salvage osteosarcoma patients. Furthermore, we analyzed the direct and indirect roles in surgical decision-making and found that ifosfamide may play a partial mediating role in the surgery option choice by mediating tumor mass volume change, tumor response, and the shortest distance from the center of main blood vessels to the margin of the tumor lesion.

A Comprehensive Understanding of the Genomic Bone Tumor Landscape: A Multicenter Prospective Study.

Complexity and heterogeneity increases the difficulty of diagnosis and treatment of bone tumors. We aimed to identify the mutational characterization and potential biomarkers of bone tumors. In this study, a total of 357 bone tumor patients were recruited and the next generation sequencing (NGS)-based YuanSu450 panel, that includes both DNA and RNA sequencing, was performed for genomic alteration identification. The most common mutated genes in bone tumors included TP53, NCOR1, VEGFA, RB1, CCND3, CDKN2A, GID4, CCNE1, TERT, and MAP2K4. The amplification of genes such as NCOR1, VEGFA, and CCND3 mainly occurred in osteosarcoma. Germline mutation analysis reveal a high frequency of HRD related mutations (46.4%, 13/28) in this cohort. With the assistance of RNA sequencing, 16.8% (19/113) gene fusions were independently detected in 20% (16/79) of patients. Nearly 34.2% of patients harbored actionable targeted mutations, of which the most common mutation is CDKN2A deletion. The different mutational characterizations between juvenile patients and adult patients indicated the potential effect of age in bone tumor treatment. According to the genomic alterations, the diagnosis of 26 (7.28%) bone tumors were corrected. The most easily misdiagnosed bone tumor included malignant giant cell tumors of bone (2.8%, 10/357) and fibrous dysplasia of bone (1.7%, 6/357). Meanwhile, we found that the mutations of MUC16 may be a potential biomarker for the diagnosis of mesenchymal chondrosarcomas. Our results indicated that RNA sequencing effectively complements DNA sequencing and increased the detection rate of gene fusions, supporting that NGS technology can effectively assist the diagnosis of bone tumors.

A novel limb-salvage reconstruction strategy with a custom hemipelvic endoprosthesis and preserved femoral head following the resection of periacetabular tumors: A preliminary study.

The treatment of periacetabular malignancy frequently challenges surgeons. To simplify the surgical procedure, we performed a novel reconstruction strategy preserving the femoral head for patients with periacetabular malignancies. We retrospectively reviewed 14 patients who underwent total en bloc resection of a periacetabular tumor and reconstruction of the hip joint with an individualized hemipelvic endoprosthesis and remaining femoral head from July 2015 to January 2019 at our center. Regions of pelvic resection: region II-4 (28.6%), region I + II-5 (35.7%), region II + III-2 (14.3%) and region I + II + III-3 (21.4%). The oncological outcomes were that 13 patients survived without disease and one patient survived with lung metastasis. None of the patients experienced local recurrence (range: 20-62 months; mean: 32 months). The incidence of postoperative complications was 35.7%, including delayed wound healing and deep venous thrombosis. No prosthesis-related complications occurred until the last follow-up in this study (range: 20-62 months; mean: 32 months). The mean Musculoskeletal Tumor Society functional outcome score was 23.2. The mean Toronto Extremity Salvage Score of the patients was 75.7 points, with a mean limb discrepancy of 1.51 cm (range: 0.5-3.2 cm). Reconstruction with preservation of the femoral head showed acceptable early functional and oncological outcomes, and it had an acceptable complication rate.

The FAP α -activated prodrug Z-GP-DAVLBH inhibits the growth and pulmonary metastasis of osteosarcoma cells by suppressing the AXL pathway.

Osteosarcoma is a kind of bone tumor with highly proliferative and invasive properties, a high incidence of pulmonary metastasis and a poor prognosis. Chemotherapy is the mainstay of treatment for osteosarcoma. Currently, there are no molecular targeted drugs approved for osteosarcoma treatment, particularly effective drugs for osteosarcoma with pulmonary metastases. It has been reported that fibroblast activation protein alpha (FAPα) is upregulated in osteosarcoma and critically associated with osteosarcoma progression and metastasis, demonstrating that FAPα-targeted agents might be a promising therapeutic strategy for osteosarcoma. In the present study, we reported that the FAPα-activated vinblastine prodrug Z-GP-DAVLBH exhibited potent antitumor activities against FAPα-positive osteosarcoma cells in vitro and in vivo. Z-GP-DAVLBH inhibited the growth and induced the apoptosis of osteosarcoma cells. Importantly, it also decreased the migration and invasion capacities and reversed epithelial-mesenchymal transition (EMT) of osteosarcoma cells in vitro and suppressed pulmonary metastasis of osteosarcoma xenografts in vivo. Mechanistically, Z-GP-DAVLBH suppressed the AXL/AKT/GSK-3ß/ß-catenin pathway, leading to inhibition of the growth and metastatic spread of osteosarcoma cells. These findings demonstrate that Z-GP-DAVLBH is a promising agent for the treatment of FAPα-positive osteosarcoma, particularly osteosarcoma with pulmonary metastases.

Survival after pulmonary metastasectomy for relapsed osteosarcoma.

OBJECTIVES: The purpose of this study was to evaluate the postrelapse survival of relapsed osteosarcoma with pulmonary metastases in patients who received pulmonary metastasectomy using intent to treat and propensity score analysis. METHODS: Patients with osteosarcoma who relapsed with pulmonary metastases between 2004 and 2018 who were treated in a hospital affiliated with a medical school were included. All the enrolled patients were evaluated as operable with assessment algorithm at the time of diagnosis of pulmonary relapse and intent to treat analysis was done. Multiple propensity score methods (eg, matching, stratification, covariate adjustment, and inverse probability of treatment weighting) were performed to balance confounding bias. Cox proportional hazards regression and the Kaplan-Meier method were used to evaluate patient survival. RESULTS: A total of 125 patients met the study criteria. Of these, 59 (47.2%) patients received pulmonary metastasectomy combined with chemotherapy and 66 (52.8%) received chemotherapy alone. The 2-year and 5-year postrelapse survival rate of metastasectomy group and nonmetastasectomy group were 68.4% versus 25.0% and 41.0% versus 0%, respectively. The median postrelapse survival was 24.9 versus 13.5 months, respectively. Pulmonary metastasectomy was independently associated with improved survival (hazard ratio, 0.185; 95% confidence interval, 0.103-0.330; P < .001). These results were confirmed by multiple propensity score analyses. Further stratified analysis revealed that the survival advantage associated with metastasectomy was not significant in patients with metastases involving ≥3 lung lobes and patients with very high pretreatment serum alkaline phosphatase (more than twice the upper limit). CONCLUSIONS: Pulmonary metastasectomy is associated with improved survival in patients with recurrent osteosarcoma.

Establishment and characterization of a highly metastatic human osteosarcoma cell line from osteosarcoma lung metastases.

OS (Osteosarcoma) is the most common malignant tumor in adolescents, and lung metastasis limits its therapeutic outcome. The present study aimed to establish a highly metastatic human OS cell line directly from lung metastases and characterize its biological functions. In this study, epithelioid tumor cells with large nucleo-cytoplasmic ratio and abundant organelles were obtained by the tissue mass adherent and repeated digestion adherent method and named ZOSL-1 cells. ZOSL-1 cells had the potential to proliferate in vitro with a doubling time of 39.28 ± 3.04 h and migrate with or without a matrix. ZOSL-1 cells were tumorigenic in vivo, and had the ability to develop lung metastasis after intratibial injection. ZOSL-1 cells expressed the osteogenic-related genes osteocalcin and osteopontin. In addition, the expression of ZOSL-1 in Fas cell surface death receptor (FAS), CD44 molecule (CD44), GNAS complex locus (GNAS), scavenger receptor class B member 1 (SCARB1), C-X-C motif chemokine receptor 4 (CXCR4), cadherin 11 (CDH11), neurofibromin 2 (NF2) and ezrin (EZR) genes may be related to its transfer efficiency. Taken together, these results indicated the high metastatic capability and important biological functions of ZOSL-1 cells. ZOSL-1 establishment provided a relevant model for the study of osteosarcoma lung metastasis.

A Novel Method to Treat Progressive Desmoid Tumors Involving Neurovascular Bundles: A Retrospective Cohort Study.

BACKGROUND: More effective therapies are needed to treat progressive desmoid tumors when active surveillance and systemic therapy fail. OBJECTIVE: To assess the efficacy and safety of sandwich isolation surgery on the local control of progressive desmoid tumors involving neurovascular bundles. METHODS: A total of 27 patients with progressive desmoid tumors at extremities involving neurovascular bundles who received surgery at our hospital between August 2014 and August 2018 were identified. A total of 13 patients received sandwich isolation surgery, in which R2 resection was performed in neurovasculature-involving regions, and a biomaterial patch was used to envelop involved neurovascular structures and isolate residual tumors. In non-neurovasculature-involving regions, wide resection was performed without isolation. A total of 14 patients received traditional surgery, which included tumor resection without isolation procedure. RESULTS: In sandwich isolation group, tumor progressions and local recurrences occurred in 3 patients outside the isolated neurovasculature-involving regions. However, no progressions or recurrences occurred in any patients in the isolated neurovasculature-involving regions where R2 resection was performed. Sandwich isolation surgery group and traditional surgery group shared similar baseline clinical characteristics. The estimated 3-yr event-free survival rate was 76.9% after sandwich isolation surgery, and 32.7% after traditional surgery (P = .025). Patients who received sandwich isolation surgery were less likely to have local recurrence (hazard ratio: 0.257, P = .040). No complications were noted except intermittent mild pain in operative regions (2 cases). CONCLUSION: Sandwich isolation surgery is effective and safe for local control of desmoid tumors involving neurovascular bundles.

Experience with periprosthetic infection after limb salvage surgery for patients with osteosarcoma.

BACKGROUND: The rate of postoperative infection developing is higher after limb salvage surgery (LSS) following sarcoma resection compared with conventional arthroplasty. The goal of this study is to summarize our experience in management of periprosthetic joint infection (PJI) and the risk factors of early PJI after LSS. METHODS: Between January 2010 and July 2019, 53 patients with osteosarcoma in the lower extremities who encountered periprosthetic infection after segmental tumor endoprosthetic replacement in our center were analyzed. Detailed patient characteristics and therapeutic information were collected from database of our institution or follow-up data and we divided patients according to the interval time between infection and tumor resection (surgery-infection interval) and investigate potential risk factors. RESULTS: A total of 53 (5.08%) patients were suffered postoperative infection. The average interval between surgery and clinical signs of deep infections are 27.5 days. For the drainage culture, positive results were only presented in 11 patients (20.8%). Almost half of this study's (47.2%) patients underwent a traditional two-stage revision, that was, after the removal of the infected prosthesis, we applied antibiotic-loaded bone cements as a spacer. The mean blood loss during initial implantation surgery and operation time both correlated with interval period between PJI and initial implantation significantly (P = 0.028, P = 0.046). For several patients which infection marker was hardly back to normal after spacer implantation, we conservatively introduced an improved combination of bone cement and prosthesis for the second-stage surgery (5.6%). There were six patients needing re-operation, of which three were due to the aseptic loosening of the prosthesis, one developed periprosthetic infection again, and two patients encountered local recurrence and underwent amputation. Two patients were dead from distal metastasis. CONCLUSIONS: A two-stage revision strategy remains effective and standardized methods for PJI patients. Total operation time and blood loss during LSS of osteosarcoma are the main risk factors of early PJI. For the patients without confirmed eradiation of microorganisms, an improved combination of bone cement and prosthesis applied in the second-stage surgery could achieve satisfied functional and oncologic results.

AHA1 upregulates IDH1 and metabolic activity to promote growth and metastasis and predicts prognosis in osteosarcoma.

Osteosarcoma (OS) is the most common primary malignant bone tumor in children and adolescents. Although activator of HSP90 ATPase activity 1 (AHA1) is reported to be a potential oncogene, its role in osteosarcoma progression remains largely unclear. Since metabolism reprogramming is involved in tumorigenesis and cancer metastasis, the relationship between AHA1 and cancer metabolism is unknown. In this study, we found that AHA1 is significantly overexpressed in osteosarcoma and related to the prognosis of osteosarcoma patients. AHA1 promotes the growth and metastasis of osteosarcoma both in vitro and in vivo. Mechanistically, AHA1 upregulates the metabolic activity to meet cellular bioenergetic needs in osteosarcoma. Notably, we identified that isocitrate dehydrogenase 1 (IDH1) is a novel client protein of Hsp90-AHA1. Furthermore, the IDH1 protein level was positively correlated with AHA1 in osteosarcoma. And IDH1 overexpression could partially reverse the effect of AHA1 knockdown on cell growth and migration of osteosarcoma. Moreover, high IDH1 level was also associated with poor prognosis of osteosarcoma patients. This study demonstrates that AHA1 positively regulates IDH1 and metabolic activity to promote osteosarcoma growth and metastasis, which provides novel prognostic biomarkers and promising therapeutic targets for osteosarcoma patients.