Rhabdomyosarcoma Research Articles

Biological Adaptations in Rhabdomyosarcoma Tumor Cells in lymph nodes: A Case Report of RMS with FUS::TFCP2 translocation

Abstract Introduction/Objective The WHO classification categorizes Rhabdomyosarcoma (RMS) into four main subtypes based on clinicopathological and molecular features. However, TFCP2-rearranged RMS, a rare tumor, does not neatly fit into any of these subtypes. Literature review identified only two reported cases of RMS with FUS::TFCP2 fusion and a round cell component. Methods/Case Report We present a rare case of RMS in lymph nodes with FUS::TFCP2 translocation in a 29-year- old female with a history of spindle cell rhabdomyosarcoma in the bilateral maxilla. The original tumor exhibited a distinctive spindle and epithelioid phenotype, coexpressing myogenic markers, epithelial markers, and ALK. FUS::TFCP2 translocation was confirmed, representing an uncommon subset of RMS. After chemotherapy, radiation, and surgery, the patient developed multiple bilateral pathologically enlarged cervical lymph nodes. Excision revealed metastatic rhabdomyosarcoma involving lymph nodes with a predominantly round cell and epithelioid morphology, with approximately 5% spindle cell growth, resembling the pattern identified in the primary resection. Results (if a Case Study enter NA) NA Conclusion Previous reports suggest that RMS with FUS::TFCP2 fusion displays a biphasic pattern, comprising solid proliferation of round cells in superficial areas and spindle cells in deeper regions. The altered cell morphology observed in our case may be attributed to the varied distribution pattern of each component with lesion depth and the cellular stress response. Previous literature reported that radiation stress potentially leads to biological adaptations of tumor cells and tumor radioresistance. Our findings underscore the distinctive phenotype of RMS with FUS::TFCP2 fusion, characterized by the coexpression of myogenic and epithelial markers, along with ALK positivity. Understanding the cellular adaptations of RMS cells could inform the development of novel clinical interventions aimed at enhancing radiosensitization and improving therapeutic efficacy, ultimately enhancing patient survival.

A comparative in vivo study of hyperthermic intraperitoneal chemotherapy with cisplatin versus doxorubicin versus cisplatin plus doxorubicin for the treatment of intra-abdominally disseminated alveolar rhabdomyosarcoma in mice.

Treatment options for advanced intra-abdominal pediatric rhabdomyosarcoma (RMS) with peritoneal sarcomatosis (PS) include cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). However, optimal dosages and combination regimens of drugs used for HIPEC are underexplored. We aimed to evaluate the efficacy of HIPEC with cisplatin, doxorubicin, and their combination in vivo. We established PS/RMS mouse model by intraperitoneally injecting RH30 cells into NOD/LtSz-scid IL2Rγ-null mice. Two weeks post xenotransplantation, mice underwent a single HIPEC procedure at 42°C for 60minutes. Treatment groups received cisplatin (50, 100, and 150mg/m2) and doxorubicin (30, 45, and 60mg/m2), administered alone or combined. The control group underwent an intraperitoneal lavage with isotonic saline. Peritoneal cancer index (PCI) was used to quantify the extent of peritoneal tumor spread. Tissue samples were evaluated regarding proliferation (Ki-67) and apoptosis (caspase 3). Mice treated with cisplatin at 100mg/m2 (PCI of 3.875, p=.007) and 150mg/m2 (PCI of 4.556, p=.026), and doxorubicin at 30mg/m2 (PCI of 2.875, p<.001) and 45mg/m2 (PCI of 4.143, p=.021) showed reduced PCI, with the combination of cisplatin 50mg/m2 and doxorubicin 30mg/m2 showing the most prominent effect (PCI of 3.333, p<.001) compared to the control group (PCI of 8.615). Histologically, there was no difference in Ki-67 or caspase 3 expression among the groups. The cisplatin- and doxorubicin-based HIPEC significantly reduces peritoneal tumor dissemination in vivo. Further investigations are needed to explore the underlying molecular responses to optimize therapeutic strategies.

Rhabdomyosarcoma Presenting as an Infective Midline Nodule on the Chin in an Eight-year-old Child

Background and Aims: Rhabdomyosarcoma (RMS) is the most common subtype of soft tissue sarcoma (STS) in children. Early diagnosis is the most favourable prognostic factor and thus physicians need to include RMS in the differential diagnosis of more common diseases developing within the head and neck region. This report highlights the same while describing a case of an eight-year-old child who presented with a chin swelling which turned out to be an RMS. Methods: We present a rare case of an eight-year-old child with a midline painless mass. Results: This child had a transoral resection of the mass. He undertook further chemotherapy and was completely cured with no tumour recurrence. Conclusion: In a painless rapidly increasing mass in the head and neck area, despite rare, but RMS should be included as a differential diagnosis. This is important as early diagnosis and proper resection and treatment are paramount in the prognosis of the disease.

The Other Site of Rhabdomyosarcoma.

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. 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. 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. 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.

Metastatic site radiation therapy for Ewing sarcoma and rhabdomyosarcoma: Consensus guidelines from the National Pediatric Cancer Foundation

BackgroundDespite the urgent need for improved outcomes in patients with metastatic Ewing sarcoma (EWS) and rhabdomyosarcoma (RMS), it is unknown how to best approach metastatic site radiation therapy for these patients and whether such treatment provides a significant oncologic benefit that outweighs the toxicities. MethodsWe gathered a panel of pediatric radiation oncologists from academic hospitals to identify and discuss current controversies regarding the role of radiation in the management of metastatic EWS and RMS. The panel reviewed existing clinical data and ongoing trials to address five key questions: 1) the role of whole lung irradiation (WLI) in treating lung metastases 2) number of metastatic sites warranting radiotherapy and the radicality of such an approach; 3) radiation techniques, including stereotactic body radiation therapy (SBRT); 4) the timing of metastatic-site radiation therapy; and 5) the utility of metastatic site radiation therapy for relapsed metastatic disease. ResultsAfter a review of existing data, consensus recommendations were developed to support the decision-making process in metastatic-site irradiation with the goal of improving long-term disease control. Patients with pulmonary metastases should receive WLI. In patients with limited (<8 sites) metastatic disease, a comprehensive approach should be taken to treat all sites of metastatic disease diagnosed at presentation. SBRT should be considered as a preferred treatment technique. The timing of metastatic-site treatment should coincide with the end of systemic therapy. However, if there is a dosimetric advantage or improved compliance, concurrent treatment with the primary site may be preferred. ConclusionsA consensus guideline was established to address several critical questions regarding the role of radiation in the treatment of metastatic EWS and RMS. The study highlights the existing controversies, provides a structured approach, and underscores the need for future studies to further evaluate the therapeutic ratio of metastatic-site directed therapy.

A CASE OF METASTATIC INTRACARDIAC RHABDOMYOSARCOMA

Intracardiac metastasis of rhabdomyosarcoma (RMS) is a rare occurrence, with only a few cases reported in the literature. RMS is a malignant tumor of skeletal muscle origin, primarily affects children and young adults and rarely adults. It is characterized by an aggressive spread, often metastasizing to the lungs, bone marrow, and lymph nodes. However, cardiac involvement is uncommon and typically presents late in the disease course, complicating management and worsening prognosis. This article explores a rare case of intracardiac metastasis of RMS, discussing the clinical presentation, diagnostic challenges, treatment modalities, and prognosis. We also review relevant literature to provide a comprehensive understanding of this rare phenomenon.

Osteosarcoma as a secondary malignancy following rhabdomyosarcoma: A report of 28 affected patients from the Cooperative Osteosarcoma Study Group (COSS).

Osteosarcoma may arise as a secondary malignancy following rhabdomyosarcoma (RMS). We utilized the Cooperative Osteosarcoma Study Group (COSS) database to better understand this association. 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. 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. 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.

Phospholipase Cδ-4 (PLCδ4) Acts as a Nuclear Player to Influence Cyclin B Expression in the Embryonal Rhabdomyosarcoma Cell Lines RD and A204.

Rhabdomyosarcoma (RMS), the most common form of sarcoma typical of pediatric age, arises from the malignant transformation of the mesenchymal precursors that fail to differentiate into skeletal muscle cells. Here, we investigated whether the protein phospholipase C δ4 (PLCδ4), a member of the PLC family involved in proliferation and senescence mechanisms of mesenchymal stromal stem cells, may play a role in RMS. Our molecular and morpho-functional data reveal that PLCδ4 is highly expressed in the fusion-negative, p53-positive, SMARCB1 heterozygous mutated embryonal RMS (ERMS) cell line A204, while it is poorly expressed in the ERMS cell lines RD (fusion-negative, MYC amplification, N-RAS (Q61H), homozygous mutated p53) and Hs729 (homozygous mutated p53) and the alveolar rhabdosarcoma (ARMS) cell line SJCRH30 (RH30; fusion positive, heterozygous mutated RARA, polyheterozygous mutated p53). To characterize the role of PLCδ4, the RD cell line was stably transfected with wild-type PLCδ4 (RD/PLCδ4). Overexpressed PLCδ4 mainly localized to the nucleus in RD cells and contributed to the phosphorylation of PRAS40 (T246), Chk2(T68), WNK1(T60), and Akt 1/273 (S473), as revealed by proteome profiler array analysis. Overexpression of PLCδ4 in RD cells enhanced cyclin B1 expression and resulted in G2/M-phase cell cycle arrest. In contrast, siRNA-mediated knockdown of PLCδ4 in A204 cells resulted in reduced cyclin B1 expression. Our study identifies a novel role for nuclear PLCδ4 as a regulator of cyclin B1 via Akt-dependent phosphorylation. The modulation of PLCδ4 expression and its downstream targets could represent a crucial signaling pathway to block embryonal RMS cell proliferation.

Disseminated pleomorphic rhabdomyosarcoma in a horse

An 8-y-old National Show Horse mare was presented for evaluation of pneumonia and laminitis. Harsh bronchovesicular sounds were auscultated throughout both lung fields, and the mare had signs of moderately painful laminitis. Thoracic ultrasonography revealed lung consolidation throughout the dorsal aspect of both lungs, and radiography revealed an extensive diffuse-to-patchy bronchointerstitial lung pattern. The mare’s clinical condition rapidly deteriorated, and euthanasia was elected. On postmortem examination, the lungs, omentum, spleen, liver, adrenal glands, kidneys, and femur contained 0.5–2.5-cm, firm, tan nodules. Histologically, the lungs, spleen, liver, kidneys, adrenal glands, omentum, left eye, and femur were infiltrated by bundles and nests of pleomorphic polygonal-to-spindloid cells intermixed with frequent multinucleate cells. Lymphatic vessels in the affected tissues were frequently distended with tumor emboli. Neoplastic cells were diffusely positive for vimentin, desmin, sarcomeric actin, myoblastic differentiation protein 1, and myogenin, supportive of the diagnosis of rhabdomyosarcoma (RMS), which is a rare neoplasm in horses. Cross-striations were not evident with H&amp;E or phosphotungstic acid–hematoxylin stains. Markedly pleomorphic neoplastic cells, multinucleate cells, and lack of cross-striations suggested the subclassification of pleomorphic RMS.

Rhabdomyosarcoma of the skull with EWSR1 fusion and ALK and cytokeratin expression: a case report.

Rhabdomyosarcoma (RMS) comprises of heterogeneous group of neoplasms that occasionally express epithelial markers on immunohistochemistry (IHC). We herein report the case of a patient who developed RMS of the skull with EWSR1 fusion and anaplastic lymphoma kinase (ALK) and cytokeratin expression as cytomorphologic features. A 40-year-old man presented with a mass in his forehead. Surgical resection was performed, during which intraoperative frozen specimens were obtained. Squash cytology showed scattered or clustered spindle and epithelioid cells. IHC revealed that the resected tumor cells were positive for desmin, MyoD1, cytokeratin AE1/ AE3, and ALK. Although EWSR1 rearrangement was identified on fluorescence in situ hybridization, ALK, and TFCP2 rearrangement were not noted. Despite providing adjuvant chemoradiation therapy, the patient died of tumor progression 10 months after diagnosis. We emphasize that a subset of RMS can express cytokeratin and show characteristic histomorphology, implying the need for specific molecular examination.

Rhabdomyosarcoma of the Biliary Tract in Children: Analysis of Single Center Experience.

Rhabdomyosarcoma (RMS) of the biliary tract is a rare tumor in children, constituting 0.5-0.8% of all pediatric RMS. Still, it is the most common malignancy in this location in children. Due to its rarity and location, it may cause diagnostic and treatment difficulties. Above all, there are no therapeutic guidelines specific for this tumor location. The aim of the study was to present an analysis of our experience with the treatment of children with biliary tract rhabdomyosarcoma (RMS) and discuss clinical recommendations for this specific location published in the literature. A retrospective analysis of medical records of eight children with biliary tree RMS treated in one center between 1996-2022 was performed. Records of eight children, five boys and three girls aged 2 yrs 6 mo to 16 yrs 9 mo (median-6 yrs) were analyzed. All patients presented with jaundice as the first symptom. In two patients, initial diagnosis of a tumor was established. For the remaining six, the primary diagnoses were as follows: choledochal cyst-one, malformation of the biliary ducts-one, choledocholithiasis-one, cholangitis-three. In four patients, the extrahepatic bile ducts were involved; in four patients, both the intrahepatic and extrahepatic bile ducts were involved. Embryonal RMS was diagnosed in seven patients (three botryoides type). Alveolar RMS was found in one patient. Biopsy (three surgical, four during endoscopic retrograde cholangiopancreatography (ERCP)) was performed in seven patients. One child underwent primary partial tumor resection (R2). Seven patients received neoadjuvant chemotherapy, followed by delayed resection in five, including liver transplantation in one (five were R0). Two patients did not undergo surgery. Radiotherapy was administered in four patients (two in first-line treatment, two at relapse/progression). Six patients (75%) are alive with no evidence of disease, with follow-up ranging from 1.2 yrs to 27 yrs (median 11 yrs. and 4 mo.). Two patients died from disease, 2 y 9 mo and 3 y 7 mo from diagnosis. Children presenting with obstructive jaundice should be evaluated for biliary tract RMS. The treatment strategy should include biopsy and preoperative chemotherapy, followed by tumor resection and radiotherapy for residual disease and in case of relapse.

Improving Individualized Rhabdomyosarcoma Prognosis Predictions Using Somatic Molecular Biomarkers.

Molecular markers, such as FOXO1 fusion genes and TP53 and MYOD1 mutations, increasingly influence risk-stratified treatment selection for pediatric rhabdomyosarcoma (RMS). This study aims to integrate molecular and clinical data to produce individualized prognosis predictions that can further improve treatment selection. Clinical variables and somatic mutation data for 20 genes from 641 RMS patients in the United Kingdom and the United States were used to develop three Cox proportional hazard models for predicting event-free survival (EFS). The 'Baseline Clinical' (BC) model included treatment location, age, fusion status, and risk group. The 'Gene Enhanced 2' (GE2) model added TP53 and MYOD1 mutations to the BC predictors. The 'Gene Enhanced 6' (GE6) model further included NF1, MET, CDKN2A, and MYCN mutations, selected through LASSO regression. Model performance was assessed using likelihood ratio (LR) tests and optimism-adjusted, bootstrapped validation and calibration metrics. The GE6 model demonstrated superior predictive performance, offering 39% more predictive information than the BC model (LR p<0.001) and 15% more than the GE2 model (LR p<0.001). The GE6 model achieved the highest discrimination with a C-index of 0.7087, a Nagalkerke R2 of 0.205, and appropriate calibration. Mutations in TP53, MYOD1, CDKN2A, MET, and MYCN were associated with higher hazards, while NF1 mutation correlated with lower hazard. Individual prognosis predictions varied between models in ways that may suggest different treatments for the same patient. For example, the 5-year EFS for a 10-year-old patient with high-risk, fusion-negative, NF1-positive disease was 50.0% (95% confidence interval: 39-64%) from BC but 76% (64-90%) from GE6. Incorporating molecular markers into RMS prognosis models improves prognosis predictions. Individualized prognosis predictions may suggest alternative treatment regimens compared to traditional risk-classification schemas. Improved clinical variables and external validation are required prior to implementing these models into clinical practice.

Anticancer and Immunomodulatory Activities of Prodigiosin Extracted and Purified from Serratia marcescens.

Prodigiosin is a naturally occurring compound produced by various bacteria, including Serratia marcescens. It is known for its diverse biological properties. The present study was conducted to extract and purify prodigiosin from Serratia marcescens and investigate its anticancer and immunomodulatory activities. S. presence was isolated from soil samples and characterized. Different solvents were used to extract prodigiosin from Serratia marcescens. The cytotoxic activity of prodigiosin was tested against human rhabdomyosarcoma (RD), rat embryo fibroblasts (REF), and human breast cancer MDA-MB-231 (MDA) epithelial cell lines. Albino mice were divided into six groups: Negative control (normal saline); positive control (injected with 100 µ l of Serratia marcesence); groups A-D were injected with 100 µ l of prodigiosin (1, 3, 6, and 9 µ g/mouse, respectively). After 14 days of treatment, whole blood samples were collected for immunomodulatory analysis. The study found that the highest yield of prodigiosin (65-230 mg/l) was obtained with methanol as the extraction solvent. Prodigiosin had a cytotoxic effect on cancer cells, particularly against MDA epithelial cells. However, it did not have a cytotoxic effect on normal cells. Immunological analysis revealed significant differences (p ≤ 0.01) in absolute neutrophil counts between the positive control and prodigiosin-treated groups, with the highest value in group C and the lowest in group A. Immunological analysis showed significant differences in neutrophil counts, IL-4, and IL-10 levels between prodigiosin-treated groups and the control group. Serratia marcescens prodigiosin showed cytotoxic effects on cancer cells and boosted IL-10 and IL-4 serum levels, acting as an immunomodulator.

The Impact of Radiation Therapy on Metastatic Rhabdomyosarcoma: Results From the EpSSG MTS 2008 Study

PurposeRadiation oncologists utilize radiation variably for children with metastatic rhabdomyosarcoma (RMS). Data from the XXXX study was retrospectively analyzed to validate the prior observation that the use of radiation is associated with improved outcomes, and guide future recommendations on radiation use in this patient group. Methods and MaterialsThe radiation delivered to 216 patients aged 0-21 years with metastatic RMS was retrospectively reviewed and classified as radical (all sites of disease irradiated within the protocol parameters), partial (some sites irradiated within the protocol parameters) and none (no radiation or delivered outside the protocol parameters). Landmark analysis excluded those with an event prior to day 221. Overall survival (OS) and progression free survival (PFS) were modelled using the Kaplan-Meier method to investigate the impact of radiation. The joint effect of treatment and known prognostic factors was examined using the Cox regression model. ResultsOverall 56 patients received radical, 104 partial and 56 no radiation per protocol. Due to non-randomised data, the groups were heterogeneous, particularly fewer sites of metatatic disease and less with bone metatases in those receiving radical radiation. 3-year PFS was 62.0% (95%CI 47.9-73.4) v 39.5% (29.8-49.1) v 30.1% (18.7-42.3)(p=0.002) for radical v partial v no radiotherapy respectively; 3-year OS was 70.1 % (55.8-80.6) v 53.1% (42.6-62.5) v 52.3% (38.3-64.5)(p=0.019) respectively. Multivariable analysis confirmed incremental improvement in OS with additional radiation with hazard ratio (HR) 1 v 1.8 v 2.4 (p=0.022) for radical v partial v no per protocol radiation. ConclusionsRadiation to all sites of disease seems to improve outcomes for children with metastatic RMS and should be considered when feasible. If not feasible, radiation is still recommended to the primary site and involved regional lymphadenopathy. Randomized clinical trials are required to confirm these findings, given the heterogeneity between the groups and potential confounding factors in this analysis.

A rare case of adult rhabdomyosarcoma with adnexal metastasis responding tonon-conventional chemotherapy

Rhabdomyosarcoma (RMS) is a pediatric soft tissue sarcoma having a rare incidence among adults. It is a highly chemo-radiosensitivetumor among the pediatric population but has poor biology in adults with dismal outcomes. Due to the rarity of adult RMS, there areno well-defined treatment guidelines for adult RMS and are mostly managed with pediatric-defined protocols but lack similar response.Here, we present the case of an adult female with extremely atypical metastatic site RMS which showed an extraordinary response tonon-pediatric protocol, rather than adult sarcoma-based protocol. This might give an idea to have more research and trials in the futureto implement adult sarcoma-based therapy among adult RMS cases.

Mecapegfilgrastim for prophylaxis of febrile neutropenia in children and adolescents with rhabdomyosarcoma or Ewing sarcoma: a prospective, single-arm, pilot study

BackgroundThe chemotherapy regimens recommended for both rhabdomyosarcoma (RMS) and Ewing sarcoma (ES) patients are myelosuppressive and can reduce the absolute neutrophil count (ANC) and subsequently increase the risk of febrile neutropenia (FN). However, only a few studies have focused on the efficacy and safety of granulocyte-colony stimulating factor (G-CSF) drugs in pediatric and adolescent patients with RMS and ES. Our objective was to investigate the efficacy and safety of mecapegfilgrastim, a biosimilar of pegfilgrastim, in prophylaxis of FN for pediatric and adolescent patients with RMS or ES.MethodsIn this single-arm, single-center, prospective study, pediatric and adolescent patients with RMS or ES were enrolled to receive either VAC (vincristine, cyclophosphamide, dactinomycin) regimen or VDC (vincristine, cyclophosphamide, doxorubicin) regimen in a 3-week cycle, followed by treatment with mecapegfilgrastim (100 μg/kg, maximum 6 mg) given at 24 h after completing chemotherapy. The primary endpoint was the incidence rate of FN. Secondary endpoints included the incidence rate of grade 4 neutropenia, duration of ANC ≤ 0.5 × 109/L, incidence rate of chemotherapy delay or reduction, use of antibiotics, and safety profile.ResultsIn total, 2 of the 30 (6.7%, 95% CI: 0.82–22.07) patients experienced FN after the first cycle of chemotherapy. Eight (26.7%, 95% CI: 12.28–45.89) patients experienced grade 4 neutropenia after receiving prophylactic mecapegfilgrastim. Eight patients experienced ANC ≤ 0.5 × 109/L with a median duration of 4.5 days; among them, 6 patients reached the lowest point of their ANC level on day 7, and 5 of them recovered by day 10. No dose reductions, delays, or discontinuation of chemotherapy was reported. Twenty-one (70.0%) patients received antibiotics during the treatment period. No patient experienced FN in the 0–5 years and the 13–18 years groups, and 2 patients experienced FN in the 6–12 years group. Two patients, 6 patients, and no patient experienced grade 4 neutropenia in the 0–5 years, 6–12 years, and 13–18 years groups, respectively.ConclusionMecapegfilgrastim showed acceptable efficacy and safety profile in pediatric and adolescent patients with RMS or ES. Further randomized studies with large sample size are warranted.Trial registrationThis clinical trial was registered at Chictr.org.cn (No.ChiCTR1900022249). Registered on March 31, 2019.

Entinostat as a combinatorial therapeutic for rhabdomyosarcoma

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).

Nanostructured Hybrid Polymer‐Lipid Drug Delivery Platforms for Rapamycin Repositioning in Anticancer Therapy

AbstractHere, hybrid polymer‐lipid nanoparticles are designed as colloidal carriers for Rapamycin, to improve the aqueous drug stability and to support the drug repositioning for cancer treatment, that is, against rhabdomyosarcoma (RMS). With this aim, Rapamycin – loaded hybrid nanoparticles are produced by using as nanoparticle core a graft copolymer obtained from the functionalization of the α,β‐poly(N‐2‐hydroxyethyl)‐DL‐aspartamide (PHEA) with Rhodamine B (RhB), Polylactic acid (PLA), the PHEA‐g‐RhB‐g‐PLA, and different phospholipids, that is, 1,2‐dipalmitoyl‐sn‐glycero‐3‐phosphocholine (DPPC) coated, pegylated and Mannose/PEG, for the surface coating. The drug loading of these samples allows for controlled release, and improves drug stability at pH 5.5 and 7.4 compared to the free drug. Chemical‐physical characterization confirms the nanostructure size below 200 nm, ideal for systemic administration, and easy re‐dispersibility in aqueous media. Moreover, biological characterization to test the potential use as antitumor agent shows induction of cytotoxicity in human rhabdomyosarcoma (RD) and macrophage (RAW) cell lines in a time‐ and concentration – dependent manner, and stimulated autophagy, comparable to the free drug. The uptake study following the fluorescence of the copolymer reveals that the hybrid nanoparticles are internalized by both tested cell lines, with a significantly higher amounts of internalized particles in the case of surface mannosylated and/or pegylated systems.

HDAC3 genetic and pharmacologic inhibition radiosensitizes fusion positive rhabdomyosarcoma by promoting DNA double-strand breaks

Radiotherapy (RT) plays a critical role in the management of rhabdomyosarcoma (RMS), the prevalent soft tissue sarcoma in childhood. The high risk PAX3-FOXO1 fusion-positive subtype (FP-RMS) is often resistant to RT. We have recently demonstrated that inhibition of class-I histone deacetylases (HDACs) radiosensitizes FP-RMS both in vitro and in vivo. However, HDAC inhibitors exhibited limited success on solid tumors in human clinical trials, at least in part due to the presence of off-target effects. Hence, identifying specific HDAC isoforms that can be targeted to radiosensitize FP-RMS is imperative. We, here, found that only HDAC3 silencing, among all class-I HDACs screened by siRNA, radiosensitizes FP-RMS cells by inhibiting colony formation. Thus, we dissected the effects of HDAC3 depletion using CRISPR/Cas9-dependent HDAC3 knock-out (KO) in FP-RMS cells, which resulted in Endoplasmatic Reticulum Stress activation, ERK inactivation, PARP1- and caspase-dependent apoptosis and reduced stemness when combined with irradiation compared to single treatments. HDAC3 loss-of-function increased DNA damage in irradiated cells augmenting H2AX phosphorylation and DNA double-strand breaks (DSBs) and counteracting irradiation-dependent activation of ATM and DNA-Pkcs as well as Rad51 protein induction. Moreover, HDAC3 depletion hampers FP-RMS tumor growth in vivo and maximally inhibits the growth of irradiated tumors compared to single approaches. We, then, developed a new HDAC3 inhibitor, MC4448, which showed specific cell anti-tumor effects and mirrors the radiosensitizing effects of HDAC3 depletion in vitro synergizing with ERKs inhibition. Overall, our findings dissect the pro-survival role of HDAC3 in FP-RMS and suggest HDAC3 genetic or pharmacologic inhibition as a new promising strategy to overcome radioresistance in this tumor.

Sociodemographic and Socioeconomic Factors Correlate with Late-Stage Pediatric Hodgkin Lymphoma and Rhabdomyosarcoma: A Report from the Children's Oncology Group Registries.

We examined the association between late-stage diagnosis and individual- and community-level sociodemographic and socioeconomic characteristics among patients with pediatric Hodgkin lymphoma and rhabdomyosarcoma (RMS). We obtained Children's Oncology Group data from 1999 to 2021 including summary stage [local (L), regional (R), and distant (D)], tumor subtype, demographics, and ZIP Code at diagnosis. We linked ZIP Codes to county-level redlining scores (C, D = greatest redlining), the Child Opportunity Index, and measures of segregation (racial dissimilarity indices). Logistic regressions calculated odds ratios for late-stage diagnosis and by race within tumor subtype. In total, 5,956 patients with Hodgkin lymphoma and 2,800 patients with RMS were included. Late-stage diagnosis of Hodgkin lymphoma was correlated with Black race [ORDistant(D) vs. regional/local (R&L) = 1.38 (1.13-1.68)], being uninsured [ORD vs. R&L = 1.38 (1.09-1.75)], and subtype [nodular sclerosis vs. Other Hodgkin lymphoma: ORD vs. R&L = 1.64 (1.34-2.01), Untyped: ORD vs. R&L = 1.30 (1.04-1.63)]. Late-stage RMS was correlated with bilingual households [ORDistant/regional(D&R) vs. local(L) = 2.66 (1.03-6.91)] and tumor type [alveolar vs. embryonal ORD vs. R&L = 6.16 (5.00-7.58)]. Community-level factors associated with late-stage Hodgkin lymphoma were greater Black (OR80-100% = 1.83; 95% CI = 1.11-3.02) and Hispanic (OR60-79% = 1.30; 95% CI = 1.05-1.60) dissimilarity indices. Late-stage diagnosis for RMS was associated with more redlined census tracts within counties (OR = 1.54; 95% CI = 1.02-2.35) and low/very low Child Opportunity Index (OR = 1.21; 95% CI = 1.02-1.45). Novel markers of community deprivation, such as redlining and racial segregation, were correlated with cancer outcomes for children with Hodgkin lymphoma and RMS in this first disparities study using Children's Oncology Group registries. The interplay of multilevel risk factors provides important consideration for efforts to improve early detection of pediatric cancer diagnosis.