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Introduction: Sarcomas with muscle differentiation (for example, rhabdomyosarcoma, leiomyosarcoma, and pleomorphic sarcoma) are uncommon in the adult bladder., Case Presentation: In this case report, we describe a 69-year-old Chinese male patient who presented to the urology outpatient clinic because of intermittent full-course macroscopic hematuria for 10 days. A B ultrasound indicated hypoechoic nodules in the right upper wall of the bladder. Transurethral resection of the bladder tumor and cystoscopic multipoint random biopsy was performed. Postoperative pathological findings showed pleomorphic rhabdomyosarcoma of the adult bladder. Later, he was transferred to the Department of Medical Oncology of our hospital for further postoperative chemotherapy. The chemotherapy regimen used was intravenous chemotherapy of dacarbazine with doxorubicin. The patient in this case has survived for 12 months postoperatively., Conclusion: From this case, our elderly patient with early pleomorphic rhabdomyosarcoma of the urinary bladder received transurethral resection of bladder tumor and postoperative chemotherapy, and there had been no recurrence 12 months postoperatively. The aforementioned treatment modality may offer a favorable prognosis., (© 2024. The Author(s).)

Background/aim: Radiation oncologists are reluctant to treat cancer in Fanconi Anemia (FA) patients due to their lack of homologous recombination repair of DNA strand breaks in normal tissues. To determine the therapeutic effects of irradiation and combination chemotherapy on cancer in syngeneic, radiosensitive FA mice, we derived transplantable cancers of the same genotype in three FA mouse strains., Materials and Methods: Fancd2-/- mice on a C57BL/6 or Sv/129 background and Fancg-/- mice (C57BL/6 background) that received 3-methylcholanthrene (3-MCA), were monitored for the development of subcutaneous tumors., Results: Tumors were induced at the site of 3-MCA injection, and tumor cell lines were established and found to be transplantable. Explanted tumors were identified as pleomorphic/rhabdomyosarcomas using immunohistochemical biomarkers., Conclusion: These transplantable FA mouse tumor cell lines should be valuable for testing effects of new radiation therapy protocols including FLASH high dose rate radiation delivery, immunotherapies, and combined radiation and chemotherapy treatments for radiosensitive FA patients., (Copyright © 2024, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Purpose: To describe clinical features, risk factors, and outcomes of patients with perineal and perianal rhabdomyosarcoma., Methods: The records of 51 patients (38 perineal and 13 perianal) enrolled on Children's Oncology Group clinical trials between 1997 and 2012 were reviewed., Results: At presentation, 53% were female, 65% were older than 10 years of age, 76% were alveolar histology, 76% were more than 5 cm, 84% were invasive, 65% were regional node positive by imaging, 49% were metastatic, only 16% were grossly resected upfront, and 25% of patients had a delayed excision. At a median follow-up of 6.13 years, estimated 5-year event-free survival (EFS) was 38% [22.17%-53.38%], and overall survival (OS) was 42% [26.66%-58.21%]. The rates of local, regional, and distant failure were 15.6%, 13.7%, 43.1%, respectively; all failures ultimately died. By univariate analysis, only age more than 10 years negatively impacted 5-year EFS (p = .023) and OS (p = .09), and IRS Group also impacted OS (p = .043). In Cox proportional hazards model, neither of these variables were significant after adjusting for other factors., Conclusion: Patients with perineal and perianal rhabdomyosarcoma have a poor overall prognosis, probably related to poor patient and disease characteristics at presentation., (© 2024 Wiley Periodicals LLC.)

Purpose: This study aims to analyze the clinicopathological characteristics and survival outcomes of tongue cancer in the pediatric population, a topic with limited existing data, using a population-based cohort., Methods: Pediatric patients diagnosed with tongue cancer from 1975 to 2018 were identified from the Surveillance, Epidemiology, and End Results (SEER) database. Survival rates were assessed using Kaplan-Meier analysis. Univariate survival analysis was conducted with the log-rank test, while multivariate analysis involved Cox proportional-hazards regression to identify factors influencing overall survival (OS). A predictive nomogram was developed based on Cox regression findings., Results: In total, 97 pediatric patients with tongue cancer were identified, with a median age at diagnosis of 15 years (range: 1-19 years). Tumors were classified as squamous cell carcinoma (45.4%), rhabdomyosarcoma (RMS) (13.4%), and others (41.2%). Of the patients, squamous cell carcinoma was more common in older children, whereas rhabdomyosarcoma was more common in younger children. The Cox proportional hazard regression revealed that histology and surgery were significant independent predictors of overall survival. The chance of death increased with no surgery. Moreover, patients with squamous cell carcinoma or rhabdomyosarcoma have a poorer survival percentage than patients with other subtypes., Conclusions: Tongue cancer in children is rare and associated with poor survival outcomes. This study highlights the significance of tumor histology and surgical intervention in determining overall survival, offering valuable insights for clinical decision-making in pediatric tongue cancer., (© 2024 Wiley Periodicals LLC.)

Background: Rhabdomyosarcoma (RMS) is the most common pediatric soft tissue sarcoma, with embryonal (ERMS) and alveolar (ARMS) representing the two most common histological subtypes. ARMS shows poor prognosis, being often metastatic at diagnosis. Thus, the discovery of novel biomarkers predictive of tumor aggressiveness represents one of the most important challenges to overcome and may help the development of tailored therapies. In the last years, miRNAs carried in extracellular vesicles (EVs), small vesicles of endocytic origin, have emerged as ideal candidate biomarkers due to their stability in plasma and their tissue specificity., Methods: EVs miRNAs were isolated from plasma of 21 patients affected by RMS and 13 healthy childrens (HC). We performed a miRNA profile using the Serum/Plasma Focus microRNA PCR panels (Qiagen), and RT-qPCR for validation analysis. Statistically significant (p < 0.05) miRNAs were obtained by ANOVA test., Results: We identified nine EVs miRNAs (miR-483-5p, miR-132-3p, miR-766-3p, miR-454-3p miR-197-3p, miR-335-3p, miR-17-5p, miR-486-5p and miR-484) highly upregulated in RMS patients compared to HCs. Interestingly, 4 miRNAs (miR-335-5p, miR-17-5p, miR-486-5p and miR-484) were significantly upregulated in ARMS samples compared to ERMS. In the validation analysis performed in a larger group of patients only three miRNAs (miR-483-5p, miR-335-5p and miR-484) were differentially significantly expressed in RMS patients compared to HC. Among these, mir-335-5p was significant also when compared ARMS to ERMS patients. MiR-335-5p was upregulated in RMS tumor tissues respect to normal tissues (p = 0.00202) and upregulated significantly between ARMS and ERMS (p = 0.04). Furthermore, the miRNA expression correlated with the Intergroup Rhabdomyosarcoma Study (IRS) grouping system, (p = 0.0234), and survival (OS, p = 0.044; PFS, p = 0.025). By performing in situ hybridization, we observed that miR-335-5p signal was exclusively in the cytoplasm of cancer cells., Conclusion: We identified miR-335-5p as significantly upregulated in plasma derived EVs and tumor tissue of patients affected by ARMS. Its expression correlates to stage and survival in patients. Future studies are needed to validate miR-335-5p as prognostic biomarker and to deeply elucidate its biological role., (© 2024. The Author(s).)

Background: Rhabdomyosarcoma (RMS) is a rare malignant soft tissue sarcoma (STS), accounting for almost 50% of pediatric STSs. Due to its heterogeneity, RMS presents challenges in diagnosis and treatment, with prognosis varying depending on multiple factors. Tumors localized in the other site (OTH)-including the paraspinal, perianal, thoracic, abdominal, pelvic, and perineal regions-are generally classified as unfavorable. This study assesses the clinical features and prognoses of RMS in OTH locations depending on its site of origin., Methods: An explorative analysis of RMS cases from the SEER 17 database 2000-2020 was conducted. Patients of all ages with histologically confirmed RMS as primary malignant disease classified under OTH, were included. OTH was categorized in four granular site classifications. Overall survival (OS) and disease-specific survival (DSS) were analyzed using Kaplan-Meier estimators. Factors independently influencing survival, including a site classification model presented in this study, were identified through Cox regression analysis., Results: Out of 4168 patients with RMS, 990 cases of RMS with the OTH site met the inclusion criteria. The median age was 16 years. The predominant histological subtypes were embryonal (33.0%) and alveolar (25.5%). Most tumors were ≥ 5 cm (median 9 cm) and located primarily in the pelvic region (41.5%). The 3-, 5-, and 10-year OS rates were 45.4% ± 3.332 (95% CI), 40.7 ± 3.332, and 38.6% ± 3.332, respectively, while DSS rates were 43.3% ± 3.136 (95% CI), 38.3% ± 3.136, and 35.1% ± 3.332. In the multivariate analysis age, histological type, site in a granular categorization, stage, regional lymph node examination, and regional lymph node involvement (pathologically proven) were independently associated with survival. Through both univariate and multivariate analyses, an OTH favorable group could be established. The OTH favorable group consists of the anal region, gallbladder and biliary tract, and breast., Conclusion: RMS in OTH shows significant differences in prognosis, putting the current categorization as unfavorable into question and making a more detailed classification necessary. Furthermore, pathological regional lymph node assessment is specifically in the OTH localization recommended., (© 2024 The Author(s). Cancer Medicine published by John Wiley & Sons Ltd.)

Rhabdomyosarcoma (RMS) of the urinary bladder in adults and elderly is an exceptionally rare neoplasm that displays poorly differentiated solid (alveolar-like) small cell pattern, frequently indistinguishable from small cell neuroendocrine carcinoma (SCNEC). However, the histogenesis of RMS and SCNEC and their inter-relationship have not been well studied and remained controversial. We herein analyzed 23 SCNEC and 3 small round cell RMS of the bladder for neuroendocrine (synaptophysin + chromogranin A) and myogenic (desmin + myogenin) marker expression and for TERT promoter mutations. In addition, the RMS cohort and one SCNEC that was revised to RMS were tested for gene fusions using targeted RNA sequencing (TruSight Illumina Panel which includes FOXO1 and most of RMS-related other genes). Overall, significant expression of myogenin and desmin was observed in one of 23 original SCNEC justifying a revised diagnosis to RMS. On the other hand, diffuse expression of synaptophysin was noted in 2 of the 4 RMS, but chromogranin A was not expressed in 3 RMS tested. TERT promoter mutations were detected in 15 of 22 (68%) SCNEC and in two of three (67%) assessable RMS cases, respectively. None of the four RMS cases had gene fusions. Our data highlights phenotypic and genetic overlap between SCNEC and RMS of the urinary bladder. High frequency of TERT promoter mutations in SCNEC is in line with their presumable urothelial origin. In addition, the presence of TERT promoter mutation in 2 of 3 RMS and lack of FOXO1 and other gene fusions in all 4 RMSs suggest a mucosal (urothelial) origin, probably representing extensive monomorphic rhabdomyoblastic transdifferentiation in SCNEC., (© 2024. The Author(s).)

Background: Orbital rhabdomyosarcoma (RMS), the most common primary malignant orbital tumor in childhood, presents unique challenges in management due to its genetic basis and abnormal cellular proliferation. Management has evolved from surgical excision to multimodal approaches, including surgery, radiotherapy, and chemotherapy. This review explores trends in epidemiology, pathophysiological insights, and treatment evolution to delineate optimal therapeutic strategies., Methods: A literature search was conducted across PubMed and Scopus databases up to March 4, 2024, using keywords related to orbital RMS. Studies were selected based on predefined criteria, focusing on clinical presentation, diagnostic modalities, management strategies, and outcomes. Data extraction and analysis were performed independently by 2 reviewers, with quality assessment based on the Oxford Center for Evidence-Based Medicine 2011 guidelines and Joanna Briggs Institute checklists., Results: The review synthesized data from 17 studies, highlighting demographic patterns, clinical characteristics, staging, and treatment approaches. Most patients were male and white, with a higher proportion of early-stages diagnoses. The embryonal subtype was the most common, and treatment has shifted toward radiation therapy and combined modalities. In orbital RMS, several modalities are applied in treatment. There are radiotherapy, surgical interventions, and chemotherapy. Recent studies put more emphasis on the long-term outcome of the disease about orbital bone development and facial symmetry., Conclusions: Management of orbital RMS has evolved significantly, with a current emphasis on multimodal treatment strategies. Future research should focus on optimizing therapeutic approaches to balance effective tumor control with the preservation of orbital function and esthetics., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children. Despite bone metastases being present in 5% of patients at diagnosis, there are limited studies examining these outcomes. We sought to define the prognostic factors, clinical courses, and outcomes of children treated on Children's Oncology Group (COG) clinical trials with RMS metastatic to bone at diagnosis., Methods: We performed a retrospective analysis of patients diagnosed with bone metastatic RMS enrolled on COG RMS clinical trials (D9802, D9803, ARST0431, or ARST08P1) between 1997 and 2013., Results: RMS metastatic to bone was identified in 154 patients at a median age of 14.9 years at diagnosis. Fifty-eight percent of patients were male, 90% had metastases at additional sites, 74% had alveolar histology, and extremity was the most common primary site (31%). Eighty-six percent of patients (n = 133) received radiation therapy. The 3- and 5-year event-free survival (EFS) was 15.4% and 14.5%, respectively. The 3- and 5-year overall survival (OS) was 30.4% and 18.0%, respectively. We identified alveolar histology, FOXO1 fusion presence, unfavorable primary location, higher Oberlin score, and lack of radiation as poor prognostic characteristics for both EFS and OS in univariate analysis. Lack of radiation was not significant when excluding patients with events prior to 20 weeks., Conclusions: This study is the largest analysis of patients with bone metastatic RMS, and defines the poor overall outcomes and negative prognostic factors for these patients. They may be eligible for therapy deintensification for improved quality of life or pursuit of novel treatments/approaches, which are desperately needed., (© 2024 Wiley Periodicals LLC.)

The identification of gene fusions in rare sarcoma subtypes can have diagnostic, prognostic, and therapeutic impacts for advanced cancer patients. Here, we present a case of a 31-year-old male with a lytic lesion of the left mandible initially diagnosed as an osteosarcoma but found to have a TFCP2 fusion and ALK alteration, redefining the diagnosis and providing rationale for a novel treatment strategy. Histologically, the tumor displayed hypercellular, spindled to epithelioid neoplasm and nuclear pleomorphism, while immunohistochemistry showed diffuse SATB2 and focal desmin staining. Whole genome and transcriptome analysis revealed a FUS::TFCP2 fusion, the defining alteration of a rare molecularly characterized subtype of soft tissue sarcoma termed intraosseous rhabdomyosarcoma. An internal ALK deletion and extremely high ALK RNA expression were also identified, suggesting potential benefit of an ALK inhibitor. This patient displayed a rapid and dramatic clinical and radiographic response to an ALK inhibitor, alectinib. Unfortunately, the response was short-lived, likely due to the advanced stage and aggressiveness of the disease. This report describes genome and transcriptome characterization of an intraosseous rhabdomyosarcoma, few of which exist in the literature, as well as providing evidence that inhibition of ALK may be a rational treatment strategy for patients with this exceedingly rare soft tissue sarcoma subtype characterized by TFCP2 fusions and ALK activation., (© 2024 The Author(s). Genes, Chromosomes and Cancer published by Wiley Periodicals LLC.)

Purpose: The present study aimed to determine the dose-response relationship between targeted nanocarriers released from a novel, sustained release formulation and their ability to specifically deplete cells responsible for the development of posterior capsular opacification (PCO) in month-long, dynamic cell cultures. Methods: Injectable, thermosensitive poly(D,L-lactic-co-glycolic acid)-b-poly(ethylene glycol)-b-poly(D,L-lactic-co-glycolic acid) triblock copolymer hydrogels were loaded with either a low or a high dose of doxorubicin-loaded antibody-targeted nanocarriers (G8:3DNA:Dox). Human rhabdomyosarcoma cells, selected for their expression of PCO marker brain-specific angiogenesis inhibitor 1 (BAI1), were kept under dynamic media flow and received either a low or high dose of nanocarriers. Cells were fixed and stained at predetermined time points to evaluate targeted depletion of BAI1+ cells. Results: A lower dose of nanocarriers in hydrogel depleted BAI1+ cells at a slower rate than the higher dose, whereas both reached over 90% BAI1+ cellular nonviability at 28 days. Both treatment groups also significantly lowered the relative abundance of BAI1+ cells in the population compared with the control group. Conclusions: Controlled release of a lower dose of nanocarriers can still achieve therapeutically relevant effects in the prevention of PCO, while avoiding potential secondary effects associated with the administration of a higher dose.

Background: This study aimed to assess the impact that the quality of primary and subsequent surgeries has on the survival of patients with para-testicular rhabdomyosarcoma (PTRMS)., Methods: Patients with localized (IRS I-III) and metastatic (IRS IV) PTRMS were enrolled in the two Cooperative Weichteilsarkom Studiengruppe (CWS) trials (CWS-96, CWS-2002P) and the Soft Tissue Sarcoma Registry (SoTiSaR)., Results: Among 196 patients (median age, 8.4 years), 106 (54.1%) had primary complete resection. Image-defined lymph node (LN) disease was detected in 21 (11.5%) patients in the localized cohort and 12 (92.3%) patients in the metastatic cohort. The 5-year event-free survival (EFS) and overall survival (OS) were respectively 87.3% and 94.0% for the patients with localized PTRMS and 46.2% and 42.2% for the patients with metastatic PTRMS. Protocol violations during the primary surgery (PV-PS) were observed in 70 (42%) of the IRS I-III patients. This resulted in higher rates of R1/R2 resections (n = 53 [76%] vs n = 20 [21%]; p < 0.001) with a need for pretreatment re-excision (PRE) (n = 50 [83%] vs n = 10 [17%]; p < 0.001) compared with the patients undergoing correct primary surgery. Protocol violations during PRE occurred for 13 (20%) patients. Although PV-PS did not influence the 5-year EFS or OS in the localized PTRMS cohort, the unadjusted log-rank test showed that R status after PRE is a prognostic factor for 5-year OS (R1 vs R0 [81.8% vs 97.6%]; p = 0.02)., Conclusions: The quality of surgical local control in PTRMS is unsatisfactory. Emphasis should be placed on evaluating the resection status after PRE in further clinical trials., (© 2024. The Author(s).)

Competing Interests: Declaration of competing interest We declare no competing interests.

Background: Osteosarcoma may arise as a secondary malignancy following rhabdomyosarcoma (RMS). We utilized the Cooperative Osteosarcoma Study Group (COSS) database to better understand this association., Patients and Methods: The COSS database (1980-05/2023) was searched for patients whose osteosarcoma was preceded by RMS. Eligible patients were analyzed for patient-, tumor-, and treatment-related variables as well as outcomes., Results: The search revealed 28 eligible osteosarcomas (27 high-grade central, one periosteal; male:female = 16:12; median age RMS 2.1 [range: 0.9-10.0] years, osteosarcoma 13.5 [7.2-29.0] years). Genetic tumor-predisposition syndromes were documented in 12 patients. One patient had had a distinct malignancy prior to RMS, two intermittently, seven following osteosarcoma. Local RMS treatment had included radiotherapy in 20/26 cases (two unknown). Secondary osteosarcoma sites were extremity 13, trunk seven, head and neck eight; 15 osteosarcomas were radiation-associated. There was only one case of primary osteosarcoma metastases. Osteosarcoma treatment included chemotherapy (27), surgery (26), or radiotherapy (2). A macroscopically complete remission of all osteosarcoma sites was achieved in 24 cases. Median follow-up was 5.8 (range: 0.5-18.4) years after osteosarcoma and 8.1 (1.0-15.4) years for 14 survivors. Actuarial 5-year overall and event-free survival were 66% (standard error 9%) and 45% (10%), respectively. Five of 14 deaths were caused by further malignancies., Conclusion: This series offers a benchmark for patients who develop a secondary osteosarcoma after RMS. Affected patients are generally still in the pediatric age. The results obtained strongly argue for genetic predisposition testing in RMS and against therapeutic leniency in comparable situations., (© 2024 The Author(s). Pediatric Blood & Cancer published by Wiley Periodicals LLC.)

Rhabdomyosarcoma (RMS) represents one of the most lethal soft-tissue sarcomas in children. The toxic trace element arsenic has been reported to function as a radiosensitizer in sarcomas. To investigate the role of arsenic sulfide (As 4 S 4 ) in enhancing radiation sensitization in RMS, this study was conducted to elucidate its underlying mechanism in radiotherapy. The combination of As 4 S 4 and radiotherapy showed significant inhibition in RMS cells, as demonstrated by the cell counting kit-8 (CCK-8) assay and flow cytometry. Subsequently, we demonstrated for the first time that As 4 S 4 , as well as the knockdown of NFATc3 led to double-strand break (DSB) through increased expression of RAG1. In vivo experiment confirmed that co-treatment efficiently inhibited RMS growth. Furthermore, survival analysis of a clinical cohort consisting of 59 patients revealed a correlation between NFATc3 and RAG1 expression and overall survival (OS). Cox regression analysis also confirmed the independent prognostic significance of NFATc3 and RAG1.Taken together, As 4 S 4 enhances radiosensitivity in RMS via activating NFATc3-RAG1 mediated DSB. NFATc3 and RAG1 are potential therapeutic targets. As 4 S 4 will hopefully serve as a prospective radio-sensitizing agent for RMS., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Rhabdomyosarcoma (RMS) is the most common childhood soft tissue sarcoma. For the alveolar subtype (ARMS), the presence of the PAX3::FOXO1 fusion gene and/or metastases are strong predictors of poor outcome. Metastatic PAX3::FOXO1 + ARMS often responds to chemotherapies initially, only to subsequently relapse and become resistant with most patients failing to survive beyond 8 years post-diagnosis. No curative intent phase II or phase III clinical trial has been available for patients in the past 10 years (ARST0921). Thus, metastatic ARMS represents a significantly unmet clinical need. Chemotherapy resistance in ARMS has previously been attributed to PAX3::FOXO1-mediated cell cycle checkpoint adaptation, which is mediated by an HDAC3-SMARCA4-miR-27a-PAX3::FOXO1 circuit that can be disrupted by HDAC3 inhibition. In this study, we investigated the therapeutic efficacy of combining the epigenetic regulator entinostat, a Class I Histone Deacetylase (HDAC1-3) inhibitor, with RMS-specific chemotherapies in patient derived xenograft (PDX) models of RMS. We identified single agent, additive or synergistic relationships between relapse-specific chemotherapies and clinically relevant drug exposures of entinostat in three PAX3::FOXO1 + ARMS mouse models. This preclinical data provides further rationale for clinical investigation of entinostat, already known to be well tolerated in a pediatric phase I clinical trial (ADVL1513)., (© 2024. The Author(s).)

No abstract available.

Background: Rhabdomyosarcoma (RMS) is one of the most common soft tissue sarcomas in children and adolescents, in which PAX3-FOXO1 fusion gene positive patients have very poor prognosis. PAX3-FOXO1 has been identified as an independent prognostic predictor in RMS, with no currently available targeted therapeutic intervention. The novel tyrosine kinase inhibitor anlotinib exhibits a wide range of anticancer effects in multiple types of cancers; however, there have been no relevant studies regarding its application in RMS., Materials and Methods: We investigated the effects of PAX3-FOXO1 on the therapeutic efficacy of anlotinib using the CCK-8 assay, flow cytometry, invasion assay, wound healing assay, western blotting, quantitative polymerase chain reaction(qPCR), and xenograft experiments. RNA-seq and co-immunoprecipitation assays were conducted to determine the specific mechanism by which anlotinib regulates PAX3-FOXO1 expression., Results: Anlotinib effectively inhibited RMS cell proliferation and promoted apoptosis and G2/M phase arrest while impeding tumor growth in vivo. Downregulation of PAX3-FOXO1 enhances the antitumor effects of anlotinib. Anlotinib upregulates protein kinase NEK2 and increases the degradation of PAX3-FOXO1 via the ubiquitin-proteasome pathway, leading to a reduction in PAX3-FOXO1 protein levels., Conclusion: Anlotinib effectively inhibited the malignant progression of RMS and promoted degradation of the fusion protein PAX3-FOXO1. Anlotinib could be a targeted therapeutic approach to treat PAX3-FOXO1 fusion-positive RMS., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Rhabdomyosarcoma (RMS) is a solid tumor whose metastatic progression can be accelerated through interleukin-4 receptor alpha (Il4ra) mediated interaction with normal muscle stem cells (satellite cells). To understand the function of Il4ra in this tumor initiation phase of RMS, we conditionally deleted Il4ra in genetically-engineered RMS mouse models. Nullizygosity of Il4ra altered the latency, site and/or stage distribution of RMS tumors compared to IL4RA intact models. Primary tumor cell cultures taken from the genetically-engineered models then used in orthotopic allografts further defined the interaction of satellite cells and RMS tumor cells in the context of tumor initiation: in alveolar rhabdomyosarcoma (ARMS), satellite cell co-injection was necessary for Il4ra null tumor cells engraftment, whereas in embryonal rhabdomyosarcoma (ERMS), satellite cell co-injection decreased latency of engraftment of Il4ra wildtype tumor cells but not Il4ra null tumor cells. When refocusing on Il4ra wildtype tumors by single cell sequencing and cytokine studies, we have uncovered a putative signaling interplay of Il4 from T-lymphocytes being received by Il4ra + rhabdomyosarcoma tumor cells, which in turn express Ccl2, the ligand for Ccr2 and Ccr5. Taken together, these results suggest that mutations imposed during tumor initiation have different effects than genetic or therapeutic intervention imposed once tumors are already formed. We also propose that CCL2 and its cognate receptors CCR2 and/or CCR5 are potential therapeutic targets in Il4ra mediated RMS progression., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Although MYCN has been considered an undruggable target, MYCN alterations confer poor prognosis in many pediatric and adult cancers. The novel MYCN -specific inhibitor BGA002 is an antigene peptide nucleic acid oligonucleotide covalently bound to a nuclear localization signal peptide. In the present study, we characterized the pharmacokinetics (PK) of BGA002 after single and repeated administration to mice using a novel specific enzyme-linked immunosorbent assay. BGA002 concentrations in plasma showed linear PK, with dose proportional increase across the tested dose levels and similar exposure between male and female and between intravenous and subcutaneous route of administration. Repeated dosing resulted in no accumulation in plasma. Biodistribution up to 7 days after single subcutaneous administration of [ 14 C]-radiolabeled BGA002 showed broad tissues and organ distribution (suggesting a potential capability to reach primary tumor and metastasis in several body sites), with high concentrations in kidney, liver, spleen, lymph nodes, adrenals, and bone marrow. Remarkably, we demonstrated that BGA002 concentrates in tumors after repeated systemic administrations in three mouse models with MYCN amplification (neuroblastoma, rhabdomyosarcoma, and small-cell lung cancer), leading to a significant reduction in tumor weight. Taking into account the available safety profile of BGA002, these data support further evaluation of BGA002 in patients with MYCN -positive tumors.

Rhabdomyosarcoma (RMS) is a pediatric tumor that resembles undifferentiated muscle cells; yet the extent to which cell state heterogeneity is shared with human development has not been described. Using single-cell/nucleus RNA sequencing from patient tumors, patient-derived xenografts, primary in vitro cultures, and cell lines, we identify four dominant muscle-lineage cell states: progenitor, proliferative, differentiated, and ground cells. We stratify these RMS cells/nuclei along the continuum of human muscle development and show that they share expression patterns with fetal/embryonal myogenic precursors rather than postnatal satellite cells. Fusion-negative RMS (FN-RMS) have a discrete stem cell hierarchy that recapitulates fetal muscle development and contain therapy-resistant FN-RMS progenitors that share transcriptomic similarity with bipotent skeletal mesenchymal cells. Fusion-positive RMS have tumor-acquired cells states, including a neuronal cell state, that are not found in myogenic development. This work identifies previously underappreciated cell state heterogeneity including unique treatment-resistant and tumor-acquired cell states that differ across RMS subtypes., (© 2024. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

Background: While soft tissue sarcomas affect younger patients, few studies have assessed the distribution of underlying pathogenic germline variants., Patients and Methods: We retrospectively identified all pediatric and young adult patients (0-22 years) at Haukeland University Hospital, Norway (1981-2019), through clinical and pathological records. We identified n = 46 eligible patients. From these 46 patients, adequate material representing normal tissue was available for n = 41 cases (n = 24 diagnosed with rhabdomyosarcoma, 9 with synovial sarcomas, 2 with Ewing sarcomas, and 6 without further classification), with matching tumor tissue for n = 40. Normal tissue samples were analyzed for germline pathogenic variants (PVs) by targeted sequencing of 360 cancer genes., Results: Out of the 41 analyzed cases, we found PVs or likely PVs in 7 (17%). These variants were found in TP53, MUTYH, FANCC, DICER1, FANCA, MYO3A, and MYO5B. Supporting the causality of these PVs, four cases revealed loss of heterozygosity (LOH) of the wild-type allele in the tumor tissue, one patient with a PV in DICER1 had a second somatic variant in DICER1, and a patient with a PV in TP53 had the altered allele amplified in the tumor. For three out of five with available family history, a history of other cancers in relatives was recorded. Among genes with variants of uncertain significance, CHD1L was of particular interest, revealing a stop-gain and a missense variant., Interpretation: A high fraction of young patients with soft tissue sarcoma harbor PVs. Among the genes affected, we substantiate a potential role of MYO5B and propose a potential role for MYO3A.

Background: Rhabdomyosarcomas are aggressive tumors that comprise a group of morphologically similar but biologically diverse lesions. Owing to its rarity, Mixed pattern RMS (ARMS and ERMS) constitutes a diagnostic and therapeutic dilemma., Case: Herein is presented a very rare case of mixed alveolar & embryonal rhabdomyosarcoma in the uterus of a 68-year-old woman. The wall of the uterine corpus & cervix was replaced by multiple whitish-yellow, firm nodules, measuring up to 12 cm. Microscopically, the tumor was predominantly composed of round to polygonal cells arranged in nests with alveolar pattern intermingled with hypo- & hypercellular areas of more primitive cells with scattered multinucleated giant cells seen as well. Extensive sampling failed to show epithelial elements. Immunohistochemical staining showed positive staining for vimentin, desmin, myogenin, CD56 & WT-1. However, no staining was detected for CK, LCA, CD10, ER, SMA, CD99, S100, Cyclin-D1 & Olig-2. Metastatic deposits were found in the peritoneum. The patient received postoperative chemotherapy and radiotherapy but died of systemic metastases 3 months after surgery., Conclusion: The rarity of this histological tumor entity and its aggressive behavior and poor prognosis grab attention to improving recognition and treatment modalities in adults., (© 2024. The Author(s).)

PAX3/7 fusion-negative rhabdomyosarcoma (FN-RMS) is a childhood mesodermal lineage malignancy with a poor prognosis for metastatic or relapsed cases. Limited understanding of advanced FN-RMS is partially attributed to the absence of sequential invasion and dissemination events and the challenge in studying cell behavior, using, for example, non-invasive intravital microscopy (IVM), in currently used xenograft models. Here, we developed an orthotopic tongue xenograft model of FN-RMS to study cell behavior and the molecular basis of invasion and metastasis using IVM. FN-RMS cells are retained in the tongue and invade locally into muscle mysial spaces and vascular lumen, with evidence of hematogenous dissemination to the lungs and lymphatic dissemination to lymph nodes. Using IVM of tongue xenografts reveals shifts in cellular phenotype, migration to blood and lymphatic vessels, and lymphatic intravasation. Insight from this model into tumor invasion and metastasis at the tissue, cellular, and subcellular level can guide new therapeutic avenues for advanced FN-RMS., Competing Interests: Declaration of interests The authors declare no competing interests., (Published by Elsevier Inc.)

Background: Despite a multimodal approach including surgery, chemo- and radiotherapy, the 5-year event-free survival rate for rhabdomyosarcoma (RMS), the most common soft tissue sarcoma in childhood, remains very poor for metastatic patients, mainly due to the selection and proliferation of tumour cells driving resistance mechanisms. Personalised medicine-based protocols using new drugs or targeted therapies in combination with conventional treatments have the potential to enhance the therapeutic effects, while minimizing damage to healthy tissues in a wide range of human malignancies, with several clinical trials being started. In this study, we analysed, for the first time, the antitumour activity of SFX-01, a complex of synthetic d, l-sulforaphane stabilised in alpha-cyclodextrin (Evgen Pharma plc, UK), used as single agent and in combination with irradiation, in four preclinical models of alveolar and embryonal RMS. Indeed, SFX-01 has shown promise in preclinical studies for its ability to modulate cellular pathways involved in inflammation and oxidative stress that are essential to be controlled in cancer treatment., Methods: RH30, RH4 (alveolar RMS), RD and JR1 (embryonal RMS) cell lines as well as mouse xenograft models of RMS were used to evaluate the biological and molecular effects induced by SFX-01 treatment. Flow cytometry and the modulation of key markers analysed by q-PCR and Western blot were used to assess cell proliferation, apoptosis, autophagy and production of intracellular reactive oxygen species (ROS) in RMS cells exposed to SFX-01. The ability to migrate and invade was also investigated with specific assays. The possible synergistic effects between SFX-01 and ionising radiation (IR) was studied in both the in vitro and in vivo studies. Student's t-test or two-way ANOVA were used to test the statistical significance of two or more comparisons, respectively., Results: SFX-01 treatment exhibited cytostatic and cytotoxic effects, mediated by G2 cell cycle arrest, apoptosis induction and suppression of autophagy. Moreover, SFX-01 was able to inhibit the formation and the proliferation of 3D tumorspheres as monotherapy and in combination with IR. Finally, SFX-01, when orally administered as single agent, displayed a pattern of efficacy at reducing the growth of tumour masses in RMS xenograft mouse models; when combined with a radiotherapy regime, it was observed to act synergistically, resulting in a more positive outcome than would be expected by adding each exposure alone., Conclusions: In summary, our results provide evidence for the antitumour properties of SFX-01 in preclinical models of RMS tumours, both as a standalone treatment and in combination with irradiation. These forthcoming findings are crucial for deeper investigations of SFX-01 molecular mechanisms against RMS and for setting up clinical trials in RMS patients in order to use the SFX-01/IR co-treatment as a promising therapeutic approach, particularly in the clinical management of aggressive RMS disease., (© 2024. The Author(s).)

Background: The Children's Oncology Group defines intermediate-risk rhabdomyosarcoma as unresected FOXO1 fusion-negative disease arising at an unfavourable site or non-metastatic FOXO1 fusion-positive disease. Temsirolimus in combination with chemotherapy has shown promising activity in patients with relapsed or refractory rhabdomyosarcoma. We aimed to compare event-free survival in patients with intermediate-risk rhabdomyosarcoma treated with vincristine, actinomycin, and cyclophosphamide alternating with vincristine and irinotecan (VAC/VI) combined with temsirolimus followed by maintenance therapy versus VAC/VI alone with maintenance therapy., Methods: ARST1431 was a randomised, open-label, phase 3 trial conducted across 210 institutions in Australia, Canada, New Zealand, and the USA. Eligible patients were those aged 40 years or younger with non-metastatic FOXO1-positive rhabdomyosarcoma or unresected FOXO1-negative rhabdomyosarcoma disease from unfavourable sites. Two other groups of patients were also eligible: those who had FOXO1-negative disease at a favourable site (excluding orbit) that was unresected; and those who were aged younger than 10 years with stage IV FOXO1-negative disease with distant metastases. Eligible patients had to have a Lansky performance status score of 50 or higher if 16 years or younger and a Karnofsky performance status score of 50 or higher if older than 16 years; all patients were previously untreated. Patients were randomised (1:1) in blocks of four and stratified by histology, stage, and group. Patients received intravenous VAC/VI chemotherapy with a cyclophosphamide dose of 1·2 g/m 2 per dose per cycle with or without a reducing dose of intravenous weekly temsirolimus starting at 15 mg/m 2 or 0·5 mg/kg per dose for those who weighed less than 10 kg. The total duration of therapy was 42 weeks followed by 6 months of maintenance therapy with oral cyclophosphamide plus intravenous vinorelbine for all patients. Temsirolimus was withheld during radiotherapy and for 2 weeks before any major surgical procedure. The primary endpoint was 3-year event-free survival. Data were analysed with a revised intention-to-treat approach. The study is registered with ClinicalTrials.gov (NCT02567435) and is complete., Findings: Between May 23, 2016, and Jan 1, 2022, 325 patients were enrolled. In 297 evaluable patients (148 assigned to VAC/VI alone and 149 assigned to VAC/VI with temsirolimus), the median age was 6·3 years (IQR 3·0-11·3); 33 (11%) patients were aged 18 years or older; 179 (60%) of 297 were male. 113 (77%) of 148 patients were FOXO1 negative in the VAC/VI group, and 108 (73%) of 149 were FOXO1 negative in the VAC/VI with temsirolimus group. With a median follow-up of 3·6 years (IQR 2·8-4·5), 3-year event-free survival did not differ significantly between the two groups (64·8% [95% CI 55·5-74·1] in the VAC/VI group vs 66·8% [57·5-76·2] in the VAC/VI plus temsirolimus group (hazard ratio 0·86 [95% CI 0·58-1·26]; log-rank p=0·44). The most common grade 3-4 adverse events were anaemia (62 events in 60 [41%] of 148 patients in the VAC/VI group vs 89 events in 87 [58%] of 149 patients in the VAC/VI with temsirolimus group), lymphopenia (83 events in 65 [44%] vs 99 events in 71 [48%]), neutropenia (160 events in 99 [67%] vs 164 events in 105 [70%]), and leukopenia (121 events in 86 [58%] vs 132 events in 93 [62%]). There was one treatment-related death in the VAC/VI with temsirolimus group, categorised as not otherwise specified., Interpretation: Addition of temsirolimus to VAC/VI did not improve event-free survival in patients with intermediate-risk rhabdomyosarcoma defined by their FOXO1 translocation status and clinical factors. Novel biology-based strategies are needed to improve outcomes in this population., Funding: The Children's Oncology Group (supported by the US National Cancer Institute, US National Institutes of Health)., Competing Interests: Declaration of interests We declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved, including those for text and data mining, AI training, and similar technologies.)

Background: Novel therapies are needed for relapsed and refractory rhabdomyosarcoma (RRMS). Phase II clinical trials in RRMS have typically utilized radiologic response as the primary activity endpoint, an approach that poses several limitations in RRMS. In this analysis, we aimed to estimate an event-free survival (EFS) endpoint for RRMS that could be used as a benchmark for future studies., Procedure: We performed a retrospective study of patients with RRMS enrolling on 13 single-agent phase II Children's Oncology Group and legacy group trials from 1997 to 2016. All included trials used radiographic response as their primary activity endpoint. Six-month EFS was estimated from time of trial enrollment with 95% confidence intervals. Clinical characteristics, including trial of enrollment, sex, age, race, histology, number of prior chemotherapies, and radiographic response were evaluated for their impact on 6-month EFS., Results: We identified 175 patients across 13 trials. The 6-month EFS was 16.8% (11.6%-22.8%). No differences were seen in 6-month EFS based on age, sex, race, or histology. There were nonsignificant trends toward improved 6-month EFS for patients with less than or equal to two prior lines of therapy versus higher than two, for patients enrolled on trials that achieved their primary radiographic response endpoint versus trials that did not, and for patients who achieved complete or partial response compared to those achieving stable disease., Conclusions: The prognosis of RRMS enrolled on single-agent phase II trials is poor. This pooled 6-month EFS of RRMS on single-agent trials may be used as a RRMS-specific benchmark for future single-agent phase II trials., (© 2024 Wiley Periodicals LLC.)

The dystrophin gene ( Dmd ) is recognized for its significance in Duchenne muscular dystrophy (DMD), a lethal and progressive skeletal muscle disease. Some patients with DMD and model mice with muscular dystrophy (mdx) spontaneously develop various types of tumors, among which rhabdomyosarcoma (RMS) is the most prominent. By contrast, spindle cell sarcoma (SCS) has rarely been reported in patients or mdx mice. In this study, we aimed to use metabolomics to better understand the rarity of SCS development in mdx mice. Gas chromatography-mass spectrometry was used to compare the metabolic profiles of spontaneously developed SCS and RMS tumors from mdx mice, and metabolite supplementation assays and silencing experiments were used to assess the effects of metabolic differences in SCS tumor-derived cells. The levels of 75 metabolites exhibited differences between RMS and SCS, 25 of which were significantly altered. Further characterization revealed downregulation of nonessential amino acids, including alanine, in SCS tumors. Alanine supplementation enhanced the growth, epithelial mesenchymal transition, and invasion of SCS cells. Reduction of intracellular alanine via knockdown of the alanine transporter Slc1a5 reduced the growth of SCS cells. Lower metabolite secretion and reduced proliferation of SCS tumors may explain the lower detection rate of SCS in mdx mice. Targeting of alanine depletion pathways may have potential as a novel treatment strategy. NEW & NOTEWORTHY To the best of our knowledge, SCS has rarely been identified in patients with DMD or mdx mice. We observed that RMS and SCS tumors that spontaneously developed from mdx mice with the same Dmd genetic background exhibited differences in metabolic secretion. We proposed that, in addition to dystrophin deficiency, the levels of secreted metabolites may play a role in the determination of tumor-type development in a Dmd- deficient background.

Competing Interests: Declaration of competing interest All authors have no conflict of interest or financial ties to disclose.

Bone marrow metastases-noted in 6% of patients with rhabdomyosarcoma-have been linked to very poor outcomes. Bilateral bone marrow sampling from iliac crests has been the gold standard for bone marrow examination in rhabdomyosarcoma, but sampling errors due to patchy bone marrow involvement may limit its sensitivity. Here, we report the case of a 6-year-old boy with embryonal rhabdomyosarcoma of the skull base and multiple 2-[ 18 F]fluoro-2-deoxy-D-glucose (2-[ 18 F]FDG)-avid bone marrow metastases visualized by positron emission tomography and computed tomography (2-[ 18 F]FDG PET/CT). His bone marrow aspirates were tumor-free. This case illustrates the diagnostic value of 2-[ 18 F]FDG PET/CT in the detection of bone marrow metastases in rhabdomyosarcoma patients, which may re-shape the definition of bone marrow disease and, ultimately, alter disease staging and risk stratification., (© 2024. The Author(s).)

Background: The objective of this study was to investigate the role of clinical factors together with FOXO1 fusion status in patients with nonmetastatic rhabdomyosarcoma (RMS) to develop a predictive model for event-free survival and provide a rationale for risk stratification in future trials., Methods: The authors used data from patients enrolled in the European Pediatric Soft Tissue Sarcoma Study Group (EpSSG) RMS 2005 study (EpSSG RMS 2005; EudraCT number 2005-000217-35). The following baseline variables were considered for the multivariable model: age at diagnosis, sex, histology, primary tumor site, Intergroup Rhabdomyosarcoma Studies group, tumor size, nodal status, and FOXO1 fusion status. Main effects and significant second-order interactions of candidate predictors were included in a multiple Cox proportional hazards regression model. A nomogram was generated for predicting 5-year event-free survival (EFS) probabilities., Results: The EFS and overall survival rates at 5 years were 70.9% (95% confidence interval, 68.6%-73.1%) and 81.0% (95% confidence interval, 78.9%-82.8%), respectively. The multivariable model retained five prognostic factors, including age at diagnosis interacting with tumor size, tumor primary site, Intergroup Rhabdomyosarcoma Studies clinical group, and FOXO1 fusion status. Based on each patient's total score in the nomogram, patients were stratified into four groups. The 5-year EFS rates were 94.1%, 78.4%, 65.2%, and 52.1% in the low-risk, intermediate-risk, high-risk, and very-high-risk groups, respectively, and the corresponding 5-year overall survival rates were 97.2%, 91.5%, 74.3%, and 60.8%, respectively., Conclusions: The results presented here provide the rationale to modify the EpSSG stratification, with the most significant change represented by the replacement of histology with fusion status. This classification was adopted in the new international trial launched by the EpSSG., (© 2024 The Authors. Cancer published by Wiley Periodicals LLC on behalf of American Cancer Society.)

Objective: To explore the imaging features of rare tumors of nasal cavity and sinuses, and to improve the understanding of these diseases, thereby aiding clinical diagnosis and treatment. Methods: The CT and MRI findings of 79 cases of rare neoplasm of nasal cavity and sinuses confirmed by pathology were retrospectively analyzed, and the imaging features were summarized. Results: Among the 79 cases, there were 16 cases of neuroendocrine carcinoma, most showing expansive and infiltrative bone destruction without hyperosteogeny and sclerosis. The sphenoid sinus exhibited a "pigeon" shape. In 28 cases of malignant melanoma, MRI signals were diverse, typical signals were rare, but mixed signals were more common. In 12 cases of rhabdomyosarcoma, MRI enhancement mostly showed "grape-like" enhancement and partial ring enhancement; There were 10 cases of olfactory neuroblastoma, the lesions were consistent with the distribution area of olfactory mucosa, most of them were lobulated, marginal nodules, and "flower ring" enhancement, and 2 cases grew across intracranial and external, with multiple cystic lesions and surrounding flaky edema bands. In 5 cases of solitary fibrous tumor, Benign tumors had regular shape and uniform density, while malignant tumors had irregular shape and uneven density, The enhancement was obviously uneven and showed a "pattern" change. There were 2 cases of sarcomatoid carcinoma, both with lobed appearance, uneven density, lamellar low-density shadow, and osteolytic bone destruction. In 4 cases of schwannoma, the enhancement showed obvious inhomogeneous enhancement. One case showed cystic necrosis, one case showed calcification, and the surrounding structure was compressed without damage. There was 1 case of neurofibroma, with many cystic components, low signal separation and compartmentalized enhancement. One case of paraganglioma showed moderate enhancement in the arterial phase and progressive enhancement in the venous phase, accompanied by significant swelling bone destruction. Conclusion: Rare tumors of nasal cavity and paranasal sinuses have distinctive imaging features. CT and MRI can effectively show the extent of the lesions and the degree of infiltration into adjacent tissues and organs, which is helpful for early clinical diagnosis and staging. However, definitive diagnosis still depends on pathology and immunohistochemistry., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Editorial Department of Journal of Clinical Otorhinolaryngology Head and Neck Surgery.)

We herein report a 37-year-old man who experienced recurrence of metastatic cardiac rhabdomyosarcoma along with intractable ventricular tachycardia (VT) 7 years after resection of rhabdomyosarcoma in his right elbow. At 36 years old, he developed VT unresponsive to radiofrequency catheter ablation (RFCA). Initially, the cardiac tumor was not detected, but it gradually grew in size at the RFCA site. A surgical biopsy confirmed the diagnosis of metastatic cardiac rhabdomyosarcoma. Despite radiation therapy, cardiac tumor progression and VT instability could not be prevented. Ultimately, the patient died 27 months after the initial documentation of VT.

Single-cell RNA sequencing (scRNA-seq) greatly advanced the understanding of intratumoral heterogeneity by identifying distinct cancer cell subpopulations. However, translating biological differences into treatment strategies is challenging due to a lack of tools to facilitate efficient drug discovery that tackles heterogeneous tumors. Developing such approaches requires accurate prediction of drug response at the single-cell level to offer therapeutic options to specific cell subpopulations. Here, we developed a transparent computational framework (nicknamed scIDUC) to predict therapeutic efficacies on an individual cell basis by integrating single-cell transcriptomic profiles with large, data-rich pan-cancer cell line screening data sets. This method achieved high accuracy in separating cells into their correct cellular drug response statuses. In three distinct prospective tests covering different diseases (rhabdomyosarcoma, pancreatic ductal adenocarcinoma, and castration-resistant prostate cancer), the predicted results using scIDUC were accurate and mirrored biological expectations. In the first two tests, the framework identified drugs for cell subpopulations that were resistant to standard-of-care (SOC) therapies due to intrinsic resistance or tumor microenvironmental effects, and the results showed high consistency with experimental findings from the original studies. In the third test using newly generated SOC therapy-resistant cell lines, scIDUC identified efficacious drugs for the resistant line, and the predictions were validated with in vitro experiments. Together, this study demonstrates the potential of scIDUC to quickly translate scRNA-seq data into drug responses for individual cells, displaying the potential as a tool to improve the treatment of heterogenous tumors., Significance: A versatile method that infers cell-level drug response in scRNA-seq data facilitates the development of therapeutic strategies to target heterogeneous subpopulations within a tumor and address issues such as treatment failure and resistance., (©2024 American Association for Cancer Research.)

Rhabdomyosarcoma (RMS) is a highly aggressive pediatric cancer with features of skeletal muscle differentiation. More than 80% of the high-risk patients ultimately fail to respond to chemotherapy treatment, leading to limited therapeutic options and dismal prognostic rates. The lack of response and subsequent tumor recurrence is driven in part by stem cell-like cells, the tumor subpopulation that is enriched after treatment, and characterized by expression of the AXL receptor tyrosine kinase (AXL). AXL mediates survival, migration, and therapy resistance in several cancer types; however, its function in RMS remains unclear. In this study, we investigated the role of AXL in RMS tumorigenesis, migration, and chemotherapy response, and whether targeting of AXL with small-molecule inhibitors could potentiate the efficacy of chemotherapy. We show that AXL is expressed in a heterogeneous manner in patient-derived xenografts (PDX), primary cultures and cell line models of RMS, consistent with its stem cell-state selectivity. By generating a CRISPR/Cas9 AXL knock-out and overexpressing models, we show that AXL contributes to the migratory phenotype of RMS, but not to chemotherapy resistance. Instead, pharmacologic blockade with the AXL inhibitors bemcentinib (BGB324), cabozantinib and NPS-1034 rapidly killed RMS cells in an AXL-independent manner and augmented the efficacy of the chemotherapeutics vincristine and cyclophosphamide. In vivo administration of the combination of bemcentinib and vincristine exerted strong antitumoral activity in a rapidly progressing PDX mouse model, significantly reducing tumor burden compared with single-agent treatment. Collectively, our data identify bemcentinib as a promising drug to improve chemotherapy efficacy in patients with RMS., (©2024 The Authors; Published by the American Association for Cancer Research.)

Approximately one third of children with rhabdomyosarcoma relapse or have refractory disease. Treatment approaches include a combination of systemic therapies and local therapies, directed at tumour site(s). This review was conducted to evaluate the effectiveness and safety of the combination of surgery and brachytherapy as local therapy for treating children and young people with relapsed/refractory rhabdomyosarcoma. This review identified studies based on a previous systematic review looking at the treatments for children and young people under 18 years old with relapsed/refractory rhabdomyosarcoma. Studies conducted after 2000 were included. Survival outcomes, relapse rates, adverse events and functional outcomes were extracted. From 16,965 records identified in the baseline systematic review, 205 included the words 'AMORE' or 'brachytherapy', and were screened for eligibility in this substudy. Thirteen studies met the inclusion criteria for Local-REFoRMS, including over 55 relapsed and refractory rhabdomyosarcoma patients. Most studies were retrospective cohort studies conducted within Europe. Most patients had embryonal disease within the head and neck or bladder/prostate regions, and received local therapy for first relapse. Approximately one quarter of patients relapsed following surgery and brachytherapy, with local relapses occurring more than metastatic relapse. Adverse events and functional outcomes were infrequently reported, but related to the site of surgery and brachytherapy. Study quality was limited by inconsistent reporting and potential selection bias. Outcomes following surgery and brachytherapy for a selected group of relapsed and refractory rhabdomyosarcoma show reasonable benefits, but reporting was often unclear and based on small sample sizes., (© 2024 The Authors. Pediatric Blood & Cancer published by Wiley Periodicals LLC.)

Herein, four silver(I) complexes bearing acetylated d-galactopyranoside-based N-heterocyclic carbene ligands were synthesized and fully characterized by elemental analysis, NMR, and X-ray photoelectron spectroscopy. All complexes were obtained with an anomeric β-configuration and as monocarbene species. In this study, we investigated the biological effects of the silver(I) complexes 2a-d on the human rhabdomyosarcoma cell line, RD. Our results show concentration-dependent effects on cell density, growth inhibition, and activation of key signaling pathways such as Akt 1/2, ERK 1/2, and p38-MAPK, indicating their potential as anticancer agents. Notably, at 35.5 µM, the complexes induced mitochondrial network disruption, as observed with 2b and 2c, whereas with 2a, this disruption was accompanied by nuclear content release. These results provide insight into the utility of carbohydrate incorporated NHC complexes of silver(I) as new agents in cancer therapy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Rhabdomyosarcoma (RMS) with TFCP2 rearrangement has been identified recently. This entity has a distinctive clinicopathologic features: a rapidly aggressive clinical course, a preference for the craniofacial bones, a spindle and epithelioid histomorphology, and positive immunohistochemistry for epithelial markers, ALK, and myogenic markers. RMS with TFCP2 rearrangement is rare and may be misdiagnosed as other spindle cell tumors. Here, we report a case of this entity arising in the mandible, which was initially diagnosed as ossifying fibroma in primary tumor in another hospital. A 26-year-old man presented with a recurred mass in the mandible for 1 month after the operation of mandibular tumor. The first excisional specimen was initially diagnosed as ossifying fibroma in another hospital. Histopathologic examination revealed the tumor with a hybrid spindle cell and epithelioid cytomorphology, spindle cells and spindle-to-epithelioid cells with eosinophilic and rich cytoplasm, with high-grade features, prominent nucleoli and some atypical mitosis. Immunohistochemical analysis revealed positivity for desmin, MYOD1, pan-keratin, ALK (5A4), ALK (D5F3). Based on the morphology and immunophenotype, molecular studies were performed, which revealed a FUS::TFCP2 fusion transcript, confirming the diagnosis of Rhabdomyosarcoma with FUS::TFCP2 fusion. Making a correct diagnosis is primarily dependent on awareness by the pathologist of this rare subtype of RMS and careful histopathological evaluation, supported by immunohistochemical and molecular analysis, to avoid potential diagnostic pitfalls., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Introduction: We evaluate the role of apparent diffusion coefficient (ADC) histogram metrics in stratifying pediatric and young adult rhabdomyosarcomas., Methods: We retrospectively evaluated baseline diffusion-weighted imaging (DWI) from 38 patients with rhabdomyosarcomas (Not otherwise specified: 2; Embryonal: 21; Spindle Cell: 2; Alveolar: 13, mean ± std dev age: 8.1 ± 7.76 years). The diffusion images were obtained on a wide range of 1.5 T and 3 T scanners at multiple sites. FOXO1 fusion status was available for 35 patients, nine of whom harbored the fusion. 13 patients were TNM stage 1, eight had stage 2 disease, nine were stage 3, and eight had stage 4 disease. 23 patients belonged to Clinical Group III and seven to Group IV, while two and five were CG I and II, respectively. Nine patients were classified as low risk, while 21 and five were classified as intermediate and high risk respectively. Histogram parameters of the apparent diffusion coefficient (ADC) map from the entire tumor were obtained based on manual tumor contouring. A two-tailed Mann-Whitney U test was used for all two-group, and the Kruskal-Wallis's test was used for multiple-group comparisons. Bootstrapped receiver operating characteristic (ROC) curves and areas under the curve (AUC) were generated for the statistically significant histogram parameters to differentiate genotypic and phenotypic parameters., Results: Alveolar rhabdomyosarcomas had a statistically significant lower 10th Percentile (586.54 ± 164.52, mean ± std dev, values are in ×10-6mm 2 /s) than embryonal rhabdomyosarcomas (966.51 ± 481.33) with an AUC of 0.85 (95%CI. 0.73-0.95) for differentiating the two. The 10th percentile was also significantly different between FOXO1 fusion-positive (553.87 ± 187.64) and negative (898.07 ± 449.38) rhabdomyosarcomas with an AUC of 0.83 (95% CI 0.71-0.94). Alveolar rhabdomyosarcomas also had statistically significant lower Mean, Median, and Root Mean Squared ADC histogram values than embryonal rhabdomyosarcomas. Four, five, and seven of the 18 histogram parameters evaluated demonstrated a statistically significant increase with higher TNM stage, clinical group, assignment, and pretreatment risk stratification, respectively. For example, Entropy had an AUC of 0.8 (95% CI. 0.67-0.92) for differentiating TNM stage 1 from ≥ stage 2 and 0.9 (95% CI. 0.8-0.98) for differentiating low from intermediate or high-risk stratification., Conclusion: Our findings demonstrate the potential of ADC histogram metrics to predict clinically relevant variables for rhabdomyosarcoma, including FOXO1 fusion status, histopathology, Clinical Group, TNM staging, and risk stratification., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

Rhabdomyosarcoma with TFCP2-related fusions (TFCP2-RMS) is a rare entity that commonly affects young adults with a predilection for skeletal involvement. We herein report a 40-year-old female patient with TFCP2-RMS who was misdiagnosed as fibrous dysplasia or low-grade central osteosarcoma of the mandible by referring institutions. Histologically, the tumor showed dominant spindle cells and focal epithelioid cells with marked immature woven bone formation. Immunophenotypically, in addition to the characteristic expression of myogenic markers, ALK, and cytokeratins, tumor cells also unusually expressed osteogenic markers, such as MDM2 and SATB2. Through fluorescence in situ hybridization, the tumor cells showed EWSR1::TFCP2 gene fusion and no MDM2 gene amplification. This is a rare case of TFCP2-RMS, which was misdiagnosed as low-grade central osteosarcoma due to its presenting immunophenotype of MDM2 and SATB2, as well as extensive osteoid matrix formation., Competing Interests: Declaration of interest None., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Rhabdomyosarcoma (RMS) is a rare malignancy and the most common soft tissue sarcoma in children. Vasculogenic mimicry (VM) is a novel tumor microcirculation model different from traditional tumor angiogenesis, which does not rely on endothelial cells to provide sufficient blood supply for tumor growth. In recent years, VM has been confirmed to be closely associated with tumor progression. However, the ability of RMS to form VM has not yet been reported., Methods: Immunohistochemistry, RT-qPCR and western blot were used to test the expression level of SNAI2 and its clinical significance. The biological function in regulating vasculogenic mimicry and malignant progression of SNAI2 was examined both in vitro and in vivo. Mass spectrometry, co-immunohistochemistry, immunofluorescence staining, and ubiquitin assays were performed to explore the regulatory mechanism of SNAI2., Results: Our study indicated that SNAI2 was abnormally expressed in patients with RMS and RMS cell lines and promoted the proliferation and metastasis of RMS. Through cell tubule formation experiments, nude mice Matrigel plug experiments, and immunohistochemistry (IHC), we confirmed that RMS can form VM and that SNAI2 promotes the formation of VM. Due to SNAI2 is a transcription factor that is not easily drugged, we used Co-IP combined with mass spectrometry to screen for the SNAI2-binding protein USP7 and TRIM21. USP7 depletion inhibited RMS VM formation, proliferation and metastasis by promoting SNAI2 degradation. We further demonstrated that TRIM21 is expressed at low levels in human RMS tissues and inhibits VM in RMS cells. TRIM21 promotes SNAI2 protein degradation through ubiquitination in the RMS. The deubiquitinase USP7 and E3 ligase TRIM21 function in an antagonistic rather than competitive mode and play a key role in controlling the stability of SNAI2 to determine the VM formation and progression of RMS., Conclusion: Our findings reveal a previously unknown mechanism by which USP7 and TRIM21 balance the level of SNAI2 ubiquitination, determining RMS vasculogenic mimicry, proliferation, and migration. This new mechanism may provide new targeted therapies to inhibit the development of RMS by restoring TRIM21 expression or inhibiting USP7 expression in RMS patients with high SNAI2 protein levels., (© 2024. The Author(s).)