Rhabdomyosarcomas in adults and children: an update

Engineering an fgfr4 knockout zebrafish to study its role in development and disease

Fibroblast growth factor receptor 4 (FGFR4) has a role in many biological processes, including lipid metabolism, tissue repair, and vertebrate development. In recent years, FGFR4 overexpression and activating mutations have been associated with numerous adult and pediatric cancers. As such, FGFR4 presents an opportunity for therapeutic targeting which is being pursued in clinical trials. To understand the role of FGFR4 signaling in disease and development, we generated and characterized three alleles of fgfr4 knockout zebrafish strains using CRISPR/Cas9. To generate fgfr4 knockout crispants, we injected single-cell wildtype zebrafish embryos with fgfr4 targeting guide RNA and Cas9 proteins, identified adult founders, and outcrossed to wildtype zebrafish to create an F1 generation. The generated mutations introduce a stop codon within the second Ig-like domain of Fgfr4, resulting in a truncated 215, 223, or 228 amino acid Fgfr4 protein compared to 922 amino acids in the full-length protein. All mutant strains exhibited significantly decreased fgfr4 mRNA expression during development, providing evidence for successful knockout of fgfr4 in mutant zebrafish. We found that, consistent with other Fgfr4 knockout animal models, the fgfr4 mutant fish developed normally; however, homozygous fgfr4 mutant zebrafish were significantly smaller than wildtype fish at three months post fertilization. These fgfr4 knockout zebrafish lines are a valuable tool to study the role of FGFR4 in vertebrate development and its viability as a potential therapeutic target in pediatric and adult cancers, as well as other diseases.

Adult head and neck rhabdomyosarcoma: radiotherapy- based treatment, outcomes, and predictors of survival

BACKGROUND

Adult head and neck rhabdomyosarcoma (HNRMS) is an exceptionally rare malignancy, and there is a paucity of data and research dedicated to understanding its characteristics and management in adult populations. This study aimed to assess the outcomes and identify survival predictors in adult HNRMS.

METHODS

We retrospectively evaluated 42 adult patients (> 16 years) with HNRMS who received radiotherapy (RT)-based treatment at our institute between 2008 and 2022. We analysed the clinical characteristics and prognosis of these patients, including the locoregional recurrence-free survival (LRFS), progression-free survival (PFS), and overall survival (OS), using the Kaplan-Meier method. The chi-square and Fisher's exact tests were used to analyse differences between groups for dichotomous and categorical variables, respectively. Survival rates were calculated using the Kaplan-Meier method. Prognostic variables were assessed through univariate Cox analyses.

RESULTS

The median patient age was 28 years (range, 16-82 years). Alveolar RMS was the most common histological type, observed in 21 patients (50.0%), followed by embryonal in 16 patients (38.1%). The anatomic sites of origin were orbital in one (2.4%), parameningeal in 26 (61.9%), and non-orbital/non-parameningeal in 15 (35.7%) patients. Nineteen patients (45.2%) had regional lymph node metastasis, and five patients (11.9%) presented with distant metastatic disease. Distant metastasis (n = 17) was the primary cause of treatment failure. At a median follow-up of 47.0 months, the 5-year LRFS, PFS, and OS rates were 69.0%, 39.7%, and 41.0%, respectively. Univariate analysis revealed that tumour size, lymph node involvement, and the local treatment pattern (surgery and RT vs. RT alone) were significant predictors of survival.

CONCLUSIONS

The main failure pattern in patients with HNRMS receiving RT-based treatment was distant metastasis. Tumour size > 5 cm and lymph node involvement were predictors of worse LRFS. Multimodality local treatment, combining surgery and RT, is effective and provides survival benefits.

High-dose chemotherapy for Ewing sarcoma and Rhabdomyosarcoma: A systematic review by the Australia and New Zealand sarcoma association clinical practice guidelines working party

INTRODUCTION

Patients with high-risk or metastatic Ewing sarcoma (ES) and rhabdomyosarcoma (RMS) have a guarded prognosis. High-dose chemotherapy (HDT) with autologous stem cell transplant (ASCT) has been evaluated as a treatment option to improve outcomes. However, survival benefits remain unclear, and treatment is associated with severe toxicities.

METHODS

A systematic review was conducted, using the population, intervention, comparison outcome (PICO) model, to evaluate whether utilization of HDT/ASCT impacts the outcome of patients with ES and RMS compared to standard chemotherapy alone, as part of first line treatment or in the relapse setting. Medline, Embase and Cochrane Central were queried for publications from 1990 to October 2022 that evaluated event-free survival (EFS), overall survival (OS), and toxicities. Each study was screened by two independent reviewers for suitability. A qualitative synthesis of the results was performed.

RESULTS

Of 1,172 unique studies screened, 41 studies were eligible for inclusion with 29 studies considering ES, 10 studies considering RMS and 2 studies considering both. In ES patients with high-risk localised disease who received HDT/ASCT after VIDE chemotherapy, consolidation with melphalan-based HDT/ASCT as first line therapy conveyed an EFS and OS benefit over standard chemotherapy consolidation. Efficacy of HDT/ASCT using a VDC/IE backbone, which is now standard care, has not been established. Survival benefits are not confirmed for ES patients with metastatic disease at initial diagnosis. For relapsed/refractory ES, four retrospective studies report improvement in outcomes with HDT/ASCT with the greatest evidence in patients who demonstrate a treatment response before HDT, and in patients under the age of 14. In RMS, there is no proven survival benefit of HDT/ASCT in primary localised, metastatic or relapsed disease.

CONCLUSION

Prospective randomised trials are required to determine the utility of HDT/ASCT in ES and RMS. Selected patients with relapsed ES could be considered for HDT/ASCT.

Frontline and Relapsed Rhabdomyosarcoma (FAR-RMS) Clinical Trial: A Report from the European Paediatric Soft Tissue Sarcoma Study Group (EpSSG)

The Frontline and Relapsed Rhabdomyosarcoma (FaR-RMS) clinical trial is an overarching, multinational study for children and adults with rhabdomyosarcoma (RMS). The trial, developed by the European Soft Tissue Sarcoma Study Group (EpSSG), incorporates multiple different research questions within a multistage design with a focus on (i) novel regimens for poor prognostic subgroups, (ii) optimal duration of maintenance chemotherapy, and (iii) optimal use of radiotherapy for local control and widespread metastatic disease. Additional sub-studies focusing on biological risk stratification, use of imaging modalities, including [18F]FDG PET-CT and diffusion-weighted MRI imaging (DWI) as prognostic markers, and impact of therapy on quality of life are described. This paper forms part of a Special Issue on rhabdomyosarcoma and outlines the study background, rationale for randomisations and sub-studies, design, and plans for utilisation and dissemination of results.

Prognostic Factors in Pediatric Alveolar Rhabdomyosarcoma: SEER Analysis of 277 Cases

Alveolar rhabdomyosarcoma (ARMS) is a rare but highly aggressive cancer predominantly affecting children and adolescents. This study explores prognostic factors for pediatric and adolescent ARMS, using the Surveillance, Epidemiology, and End Results (SEER) database. Leveraging SEER data (2000-2019), we analyzed 277 cases. Employing Kaplan-Meier survival analysis and Cox proportional hazards models, we identified significant prognostic factors. Gender distribution was nearly equal (56.0% boys, 44.0% girls), with the majority (70.8%) from the white ethnic group. Primary tumors were predominantly in extremities (37.2%). Distant metastases significantly increased mortality risk (hazard ratio [HR], 3.13; 95% CI: 2.14-4.58) and regional lymph node involvement raised mortality risk (HR, 1.36; 95% CI: 0.96-1.92). Chemotherapy-only treatment had higher mortality risk than chemoradiotherapy (HR, 1.16; 95% CI: 0.97-2.67). Conclusively, our study identifies distant metastases, regional lymph node involvement, and treatment modality as crucial predictors of overall survival in pediatric ARMS.

Critical elements of pediatric rhabdomyosarcoma surgery

Rhabdomyosarcoma (RMS), the most common soft tissue sarcoma in children, requires multimodal therapy which is determined by risk group stratification. Local control may be achieved by surgical resection, radiation, or both. Resection may occur upfront or following induction chemotherapy as a delayed primary excision. An R1 resection may allow a reduction in radiation exposure; however, debulking is not indicated nor is excision of residual masses at the end of therapy. Regional lymph node assessment is an important component of surgical care, as positive nodal basins require radiation. Depending on the tumor site and biology, sentinel lymph node biopsy vs biopsy of clinically or radiographically concerning nodes is indicated. Therapeutic lymph node dissection is never indicated. Familiarity with site-specific oncologic principles for RMS and participation in a multidisciplinary team including Pediatric Oncology and Radiation Oncology are necessary components of surgical care to ensure optimal outcomes.

Spindle Cell Rhabdomyosarcoma of the Inguinal Region Mimicking a Complicated Hernia in the Adult-An Unexpected Finding

Rhabdomyosarcoma is a rare tumor that is diagnosed mostly in children and adolescents, rarely in adults, representing 2-5% of all soft tissue sarcomas. It has four subtypes that are recognized: embryonal (50%), alveolar (20%), pleomorphic (20%), and spindle cell/sclerosing (10%). The diagnosis of rhabdomyosarcoma is based on the histological detection of rhabdomyoblasts and the expression of muscle-related biomarkers. Spindle cell/sclerosing rhabdomyosarcoma consists morphologically of fusiform cells with vesicular chromatin arranged in a storiform pattern or long fascicles, with occasional rhabdomyoblasts. Also, dense, collagenous, sclerotic stroma may be seen more commonly in adults. We present a rare case of an adult who presented to the hospital with a tumor in the left inguinal area, was first diagnosed with a left strangulated inguinal hernia and was operated on as an emergency, although the diagnosis was ultimately a spindle cell rhabdomyosarcoma of the inguinal region.

Garcinol and Anacardic Acid, Natural Inhibitors of Histone Acetyltransferases, Inhibit Rhabdomyosarcoma Growth and Proliferation

Rhabdomyosarcoma (RMS) is a malignant tumour of the soft tissues. There are two main histopathological types: alveolar and embryonal. RMS occurs mainly in childhood and is a result of the deregulation of growth and differentiation of muscle cell precursors. There is an increasing amount of data indicating that numerous epigenetic alterations within chromatin and histone proteins are involved in the pathogenesis of this malignancy. Histone acetylation is one of the most important epigenetic modifications that is catalysed by enzymes from the group of histone acetyltransferases (HAT). In this study, the impact of the natural histone acetyltransferase inhibitors (HATi)-garcinol (GAR) and anacardic acid (AA)-on the biology of RMS cells was evaluated through a series of in vitro tests measuring proliferation, viability, clonogenicity, cell cycle and apoptosis. Moreover, using oligonucleotide microarrays and real-time PCR, we identified several genes whose expression changed after GAR and AA treatment. The examined HATi significantly reduce the invasive phenotype of RMS cells by inhibiting the growth rate, viability and clonogenic abilities. What is more, these substances cause cell cycle arrest in the G2/M phase, induce apoptosis and affect the genetic expression of the endoplasmic reticulum stress sensors. GAR and AA may serve as promising potential anti-cancer drugs since they sensitize the RMS cells to chemotherapeutic treatment.

Zebrafish her3 knockout impacts developmental and cancer-related gene signatures

HES3 is a basic helix-loop-helix transcription factor that regulates neural stem cell renewal during development. HES3 overexpression is predictive of reduced overall survival in patients with fusion-positive rhabdomyosarcoma, a pediatric cancer that resembles immature and undifferentiated skeletal muscle. However, the mechanisms of HES3 cooperation in fusion-positive rhabdomyosarcoma are unclear and are likely related to her3/HES3's role in neurogenesis. To investigate HES3's function during development, we generated a zebrafish CRISPR/Cas9 null mutation of her3, the zebrafish ortholog of HES3. Loss of her3 is not embryonic lethal and adults exhibit expected Mendelian ratios. Embryonic her3 zebrafish mutants exhibit dysregulated neurog1 expression, a her3 target gene, and the mutant her3 fails to bind the neurog1 promoter sequence. Further, her3 mutants are significantly smaller than wildtype and a subset present with lens defects as adults. Transcriptomic analysis of her3 mutant embryos indicates that genes involved in organ development, such as pctp and grinab, are significantly downregulated. Further, differentially expressed genes in her3 null mutant embryos are enriched for Hox and Sox10 motifs. Several cancer-related gene pathways are impacted, including the inhibition of matrix metalloproteinases. Altogether, this new model is a powerful system to study her3/HES3-mediated neural development and its misappropriation in cancer contexts.

Seasonality of main childhood embryonal tumours and rhabdomyosarcoma, France, 2000-2015

Few studies have investigated the seasonal patterns of embryonal tumours. Based on data from the French National Registry of Childhood Cancers, the present study aimed to investigate seasonal variations in embryonal tumour incidence rates by month of birth and by month of diagnosis. The study included 6635 primary embryonal tumour cases diagnosed before the age of 15 years over the period 2000-2015 in mainland France. Assuming monthly variations in incidence rates were homogeneous over 2000-2015, we used a Poisson regression model to test for overall heterogeneity in standardised incidence ratios (SIRs) by month of birth or diagnosis. The seasonal scan statistic method was used to detect monthly excesses or deficits of embryonal tumour cases over the whole study period. The annual reproducibility of the observed monthly variations was formally tested. An overall heterogeneity in incidence rates by month of birth was observed for rhabdomyosarcoma in boys only. Based on the month of diagnosis, a seasonality was evidenced for unilateral retinoblastoma, with a lower incidence rate in the summer (SIR_Jul-Aug  = 0.68, 95% CI = 0.52-0.87), whilst the incidence rate of rhabdomyosarcoma tended to be lower in August (SIR_Aug  = 0.68, 95% CI = 0.52-0.89). No seasonality was detected for the other embryonal tumour groups by month of birth or month of diagnosis. This study is one of the largest to have investigated the seasonality of childhood embryonal tumours. The study showed a seasonal variation in the incidence rates by month of diagnosis for unilateral retinoblastoma and rhabdomyosarcoma. Our findings are likely to reflect a delay in consultation during the summer months. However, the role of seasonally varying environmental exposures cannot be ruled out.

An uncommon perineal embryonal rhabdomyosarcoma in adult: A case report

RATIONALE

Embryonal rhabdomyosarcoma (ERMS) is a major subtype of rhabdomyosarcoma, mainly affect children. There is seldom report for perineal ERMS in adults, since its rare location and the age.

PATIENT CONCERNS

A 20-year old male adult was admitted due to the perineal mass.

DIAGNOSES

Diagnosis by histopathological examination of the biopsy sample was ERMS. Magnetic resonance imaging showed the tumor was found in the perineal region, with metastasis to pelvic cavity, right testis, lymph nodes and bone.

INTERVENTIONS

The patient received Isophosphamide and Epirubicin for 4 cycles, followed by Irinotecan and Vindesine Sulfate for 2 cycles, then cisplatin, Dacarbazine and Apatinib for 3 cycles.

OUTCOME

The patient showed no response to chemotherapy.

LESSONS

Perineal ERMS in adults is very rare. There is still no standard therapy for adult ERMS. Personalized therapy might be promising treatment for each individual.

FOXO1 and PAX5 Rearrangement in Alveolar Rhabdomyosarcoma in Saudi Pediatric Patients

Objective: In this study, we investigate the molecular rearrangement of FOXO1 in alveolar rhabdomyosarcoma (ARHS) in Saudi pediatric patients. Method: We performed a molecular detection of molecular translocation in 30 pediatric cases of ARHS using FOXO1 dual color break-apart FISH probe (ZytoLight®, 13q14.11) and PAX5 dual color break-apart FISH probe (ZytoLight®, 9p13.2). Results: All analyzable cases of ARHS demonstrated FOXO1 translocation whereas PAX5 translocation was not detected in any case. Conclusion: Although the testing for PAX5 rearrangement was based on protein-protein network analysis, our study showed that PAX5 translocation is not conspicuous in ARHS. PAX7/3::FOXO1 fusion genes feature ARMS, rendering crossreactivity between PAX7 and PAX3 a possible explanation. Nevertheless, PAX5 immunoreactivity and molecular translocation could be an adjunctive pathway that is confined to aggressive ARMS.

Baseline Characteristics, Prognostic Factors, and Treatment Outcomes for Adult Patients With Rhabdomyosarcoma (RMS)

BACKGROUND

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma of childhood, while in adults it is one of the rarer tumors. Its prognosis is better in children with current treatment modalities; however, it carries poorer prognosis in adults. Recent data on adult RMS is scarce from our part of world. We report outcomes of adult patients with RMS, and with 40 patients; it is the first study to publish such a large data from Pakistan.

METHODS

This was a retrospective study that included 64 adult patients aged 18 years and older. After data extraction and scrutiny, a total of 40 patients were segregated with diagnosis of RMS of various varieties who were treated and followed up subsequently. International Business Machines (IBM) Statistical Package for Social Sciences (SPSS), version 26 (IBM Corp., Armonk, NY) was used to evaluate all of the gathered data.

RESULTS

Embryonal RMS (ERMS) was the most common subtype. Factors favoring better overall survival (OS) at 5 years were absence of nodal and distal metastases, treatment with surgery, margin negative resection, and absence of residual disease on postoperative imaging. Adjuvant radiation therapy (XRT) for positive resection margins as well as for residual disease on postoperative imaging also favored better OS at 5 years. Chemotherapy did impart a trend towards better OS; however, it was not significant. Histopathologic subtype and tumor size did not have any significant impact on outcomes. Median progression free survival (PFS) was 11 months and median OS was 15 months.

CONCLUSIONS

Adult RMS is a rare disease entity with widely heterogeneous clinical picture and poorer outcomes as compared to the disease of childhood and adolescence. Further prospective studies with larger sample size are required to establish role of patient, disease, and treatment-related factors affecting outcomes in our population.

Rhabdomyosarcoma in children: Retrospective analysis from a single tertiary care center in Saudi Arabia

BACKGROUND

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children occurring most commonly in the head and neck region. The treatment involves using a multimodality approach including chemotherapy, surgery, and radiation therapy. Survival for patients with localized disease has improved markedly, but the treatment of advanced disease remains a challenge. We report the clinical characteristics and outcome for patients treated at a tertiary care center in Saudi Arabia.

METHODS

Patients aged 0-14 years diagnosed with RMS between 2005 and 2018 were included. Statistical analysis was performed using SPSS software. Kaplan-Meier method was used to calculate overall and event free survival. Cox proportional hazards model was used for multivariate analysis.

RESULTS

One hundred and twenty-four patients were analyzed. The median age was 5.7 years with male predominance (2.4:1). The most common primary sites were head/neck (30%) and the genitourinary tract (25%). Embryonal RMS was present in 81%; alveolar in 19%. Most patients had intermediate risk disease (60%). The 5-year overall and event free survivals were 64.3% and 53.3%, respectively. Survival was influenced by primary tumor site, histology, and clinical risk group. Unfavorable primary site, high risk stratification, and poor initial response to therapy predicted a poor outcome.

CONCLUSION

This study provides an insight on the current management outcomes for our patients with RMS. Cytogenetics and molecular diagnostics need to be incorporated as standard of care in the therapeutic approach of our patients. In addition, there is a need for national collaborative efforts to improve the outcome of RMS in children and adolescents.

Rhabdomyosarcomas are oncogene addicted to the activation of AVIL

Rhabdomyosarcoma (RMS) is one of the most common pediatric soft-tissue cancer. Previously, we discovered a gene fusion, MARS-AVIL formed by chromosomal inversion in RMS. Suspecting that forming a fusion with a housekeeping gene may be one of the mechanisms to dysregulate an oncogene, we investigated AVIL expression and its role in RMS. We first showed that MARS-AVIL translates into an in-frame fusion protein, which is critical for RMS cell tumorigenesis. Besides forming a gene fusion with the housekeeping gene, MARS, the AVIL locus is often amplified, and its RNA and protein expression are overexpressed in the majority of RMSs. Tumors with AVIL dysregulation exhibit evidence of oncogene addiction: Silencing MARS-AVIL in cells harboring the fusion, or silencing AVIL in cells with AVIL overexpression, nearly eradicated the cells in culture, as well as inhibited in vivo xenograft growth in mice. Conversely, gain-of-function manipulations of AVIL led to increased cell growth and migration, enhanced foci formation in mouse fibroblasts, and most importantly transformed mesenchymal stem cells in vitro and in vivo. Mechanistically, AVIL seems to serve as a converging node functioning upstream of two oncogenic pathways, PAX3-FOXO1 and RAS, thus connecting two types of RMS associated with these pathways. Interestingly, AVIL is overexpressed in other sarcoma cells as well, and its expression correlates with clinical outcomes, with higher levels of AVIL expression being associated with worse prognosis. AVIL is a bona fide oncogene in RMS, and RMS cells are addicted to its activity.

Adult embryonal rhabdomyosarcoma in the nasal cavity; a case report with a review of the literature

Introduction

Rhabdomyosarcoma (RMS) is a primitive malignant soft tissue tumor arising from premature mesenchymal cells. The current study presents a rare case of embryonal rhabdomyosarcoma in the nasal cavity of an adult patient.

Case presentation

An 18-year-old female presented with right nasal obstruction for five months. Examination showed a pale soft, painless mass in the right nasal cavity with attachment to the nasal septum at the osteocartilaginous junction. The patient was falsely suspected for bacterial infection, but later histological examination showed undifferentiated small round blue cell tumor with extensive necrosis. Immunohistochemistry confirmed the diagnosis of embryonal RMS. The patient was operated on for endoscopic sinus surgery to remove the mass with additional cleaning of surrounding sinuses.

Discussion

Embryonal RMS is a rare type of malignant tumor that mostly affects the head and neck area in children while usually occur in the extremities of adults. Encountering an adult ERMS of the nasal chambers represents a small portion of head and neck cases that lack specific presentations.

Conclusion

Adult embryonal RMS of the nasal cavity is exceedingly rare and presents a diagnostic and management challenge, with immunohistochemistry being the only definitive diagnostic method.

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Embryonal rhabdomyosarcoma is a malignant soft tissue tumor of the pediatric population.

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Specific presentation and symptoms regarding Embryonal rhabdomyosarcoma of the nasal cavity is lacking.

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The recommended management is surgical excision with radiotherapy and chemotherapy.

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This report presents a case of adult Embryonal rhabdomyosarcoma occurring in nasal cavity.

Primary Pleomorphic Omental Rhabdomyosarcoma in an Adult: A Report of a Unique Case

Rhabdomyosarcoma (RMS) is a very rare, highly malignant neoplasm thought to originate from the pluripotent mesenchymal tissue. Predominantly diagnosed among children and teenagers, however they can also be encountered in adults. There are a few risk factors associated with RMS like family history of malignancy and genetic syndromes like neurofibromatosis type 1, Li-Fraumeni syndrome, Noonan syndrome and Beckwith-Wiedemann syndrome; however, most cases of RMS are sporadic. Other factors like radiotherapy for other malignancy and pre-natal radiation exposure also are associated with increased risk of developing RMS. The most common reported sites for RMS are head, neck, trunk, pelvis and lower limbs. Omental involvement of primary RMS has been rarely reported in the literature. Principally, the survival of treated RMS cases has improved, primarily due to multidisciplinary management approaches. In this paper, we report a case of primary pleomorphic RMS in a 50-year-old female who presented with abdominal pain.

Pleomorphic Rhabdomyosarcoma on the Lumbal in Adult Patient: A Case Report

BACKGROUND: The incidence of Rhabdomyosarcoma in children found at the top of age 5-15 years, with median age about 10 years. In adult, the tumor occurs about 10 % of all cases. PRMS is a very rare subtype of RMS and almost exclusively in male patient older than 45 years. Approximately 40% of RMS occurs in the head and neck region, RMS in the trunk is rare. RMS arising from the paraspinal area only comprises 3.3% of all cases.   CASE REPORTS: This case report described a 38 years-old male with lump on his back, since 1 year ago and enlarge slowly until bigger than a tennis ball, with no neurological deficit. Based on MRI with contrast there’s a solid mass on the subcutis on the level L4-5 with size 7,5 x 3 x 7,2 cm. Patient was underwent wide excision and the histopathology examination was referred to Pleomorphic Rhabdomyosarcoma. Patient underwent radiotherapy procedure for 1 month in outpatient clinic, with maximum dose radiotherapy 60 Gy, and patient underwent 30 times session of radiotherapy with dose 2 Gy for each session. After 1,5 years of control there’s no sign of recurrences.                                                                                                                              RESULTS: Based on clinical, radiologic, and histological examination, the diagnosis of pleomorphic rhabdomyosarcoma confirmed by an expert pathology consultant. Immunohistochemical examination was performed, and patient underwent wide excision and definitive radiotherapy.   DISCUSSION: Pleomorphic Rhabdomyosarcoma on the back is extremely rare and difficult to distinguish histologically. This is a very valuable case, which highlights the need for orthopedic surgeons to re-evaluate clinical and histologic finding carefully when diagnosing patients with soft tissue tumor on the lumbal region.

Splice-switching of the insulin receptor pre-mRNA alleviates tumorigenic hallmarks in rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is an aggressive pediatric tumor with a poor prognosis for metastasis and recurrent disease. Large-scale sequencing endeavors demonstrate that Rhabdomyosarcomas have a dearth of precisely targetable driver mutations. However, IGF-2 signaling is known to be grossly altered in RMS. The insulin receptor (IR) exists in two alternatively spliced isoforms, IR-A and IR-B. The IGF-2 signaling molecule binds both its innate IGF-1 receptor as well as the insulin receptor variant A (IR-A) with high affinity. Mitogenic and proliferative signaling via the canonical IGF-2 pathway is, therefore, augmented by IR-A. This study shows that RMS patients express increased IR-A levels compared to control tissues that predominantly express the IR-B isoform. We also found that Hif-1α is significantly increased in RMS tumors, portraying their hypoxic phenotype. Concordantly, the alternative splicing of IR adapts to produce more IR-A in response to hypoxic stress. Upon examining the pre-mRNA structure of the gene, we identified a potential hypoxia-responsive element, which is also the binding site for the RNA-binding protein CUG-BP1 (CELF1). We designed Splice Switching Oligonucleotides (SSO) against this binding site to decrease IR-A levels in RMS cell lines and, consequently, rescue the IR-B expression levels. SSO treatment resulted in a significant reduction in cell proliferation, migration, and angiogenesis. Our data shows promising insight into how impeding the IGF-2 pathway by reducing IR-A expression mitigates tumor growth. It is evident that Rhabdomyosarcomas use IR alternative splicing as yet another survival strategy that can be exploited as a therapeutic intervention in conjunction with already established anti-IGF-1 receptor therapies.

Incidental Discovery of Embryonal Rhabdomyosarcoma on CT Imaging

Rhabdomyosarcoma is an uncommon soft tissue sarcoma that rarely presents in adults. Clinical presentation is dependent on site and size. We present the case of a woman who presented with acute-onset dyspnoea and whose pathology report confirmed embryonal rhabdomyosarcoma (ERMS) seen as an incidental finding on chest computed tomography. We also describe the clinical, laboratory and radiological work-up conducted to diagnose and manage ERMS in the critical care setting.

LEARNING POINTS

Rhabdomyosarcoma is a rare malignancy with a poor prognosis in adults compared with children, especially if it presents in an unfavourable primary site and has an unfavourable histological diagnosis.Immunohistochemical diagnosis remains the gold standard for embryonal rhabdomyosarcoma diagnosis and differentiation from similar malignancies on initial imaging studies.Management of adult rhabdomyosarcoma is usually multimodal with surgical resection and a combination of chemo and radiotherapy.

Flavonoids kaempferol and quercetin are nuclear receptor 4A1 (NR4A1, Nur77) ligands and inhibit rhabdomyosarcoma cell and tumor growth

BACKGROUND

Flavonoids exhibit both chemopreventive and chemotherapeutic activity for multiple tumor types, however, their mechanisms of action are not well defined. Based on some of their functional and gene modifying activities as anticancer agents, we hypothesized that kaempferol and quercetin were nuclear receptor 4A1 (NR4A1, Nur77) ligands and confirmed that both compounds directly bound NR4A1 with KD values of 3.1 and 0.93 μM, respectively.

METHODS

The activities of kaempferol and quercetin were determined in direct binding to NR4A1 protein and in NR4A1-dependent transactivation assays in Rh30 and Rh41 rhabdomyosarcoma (RMS) cells. Flavonoid-dependent effects as inhibitors of cell growth, survival and invasion were determined in XTT and Boyden chamber assays respectively and changes in protein levels were determined by western blots. Tumor growth inhibition studies were carried out in athymic nude mice bearing Rh30 cells as xenografts.

RESULTS

Kaempferol and quercetin bind NR4A1 protein and inhibit NR4A1-dependent transactivation in RMS cells. NR4A1 also regulates RMS cell growth, survival, mTOR signaling and invasion. The pro-oncogenic PAX3-FOXO1 and G9a genes are also regulated by NR4A1 and, these pathways and genes are all inhibited by kaempferol and quercetin. Moreover, at a dose of 50 mg/kg/d kaempferol and quercetin inhibited tumor growth in an athymic nude mouse xenograft model bearing Rh30 cells.

CONCLUSION

These results demonstrate the clinical potential for repurposing kaempferol and quercetin for clinical applications as precision medicine for treating RMS patients that express NR4A1 in order to increase the efficacy and decrease dosages of currently used cytotoxic drugs.

Genetic Characterization, Current Model Systems and Prognostic Stratification in PAX Fusion-Negative vs. PAX Fusion-Positive Rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children and adolescents and accounts for approximately 2% of soft tissue sarcomas in adults. It is subcategorized into distinct subtypes based on histological features and fusion status (PAX-FOXO1/VGLL2/NCOA2). Despite advances in our understanding of the pathobiological and molecular landscape of RMS, the prognosis of these tumors has not significantly improved in recent years. Developing a better understanding of genetic abnormalities and risk stratification beyond the fusion status are crucial to developing better therapeutic strategies. Herein, we aim to highlight the genetic pathways/abnormalities involved, specifically in fusion-negative RMS, assess the currently available model systems to study RMS pathogenesis, and discuss available prognostic factors as well as their importance for risk stratification to achieve optimal therapeutic management.

Loss of p16/Ink4a drives high frequency of rhabdomyosarcoma in a rat model of Duchenne muscular dystrophy

Rhabdomyosarcoma (RMS) is an aggressive type of soft tissue sarcoma, and pleomorphic RMS is a rare subtype of RMS found in adult. p16 is a tumor suppressor which inhibits cell cycle. In human RMS, p16 gene is frequently deleted, but p16-null mice do not develop RMS. We reported that genetic ablation of p16 by the crossbreeding of p16 knock-out rats (p16-KO rats) improved the dystrophic phenotype of a rat model of Duchenne muscular dystrophy (Dmd-KO rats). However, p16/Dmd double knock-out rats (dKO rats) unexpectedly developed sarcoma. In the present study, we raised p16-KO, Dmd-KO, and dKO rats until 11 months of age. Twelve out of 22 dKO rats developed pleomorphic RMS after 9 months of age, while none of p16-KO rats and Dmd-KO rats developed tumor. The neoplasms were connected to skeletal muscle tissue with indistinct borders and characterized by diffuse proliferation of pleomorphic cells which had eosinophilic cytoplasm and atypical nuclei with anisokaryosis. For almost all cases, the tumor cells immunohistochemically expressed myogenic markers including desmin, MyoD, and myogenin. The single cell cloning from tumor primary cells gained 20 individual Pax7-negative MyoD-positive RMS cell clones. Our results demonstrated that double knock-out of p16 and dystrophin in rats leads to the development of pleomorphic RMS, providing an animal model that may be useful to study the developmental mechanism of pleomorphic RMS.

High Frequency of Tumor Propagating Cells in Fusion-Positive Rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children. Fusion-positive RMS (FPRMS), expressing the PAX3/7-FOXO1, has a worse prognosis compared to the more common fusion-negative RMS (FNRMS). Although several studies reported hierarchical organization for FNRMS with the identification of cancer stem cells, the cellular organization of FPRMS is not yet clear. In this study we investigated the expression of key stem cell markers, developed a sphere assay, and investigated the seven most common FPRMS cell lines for subpopulations of tumor propagating cancer stem-like cells, also called cancer stem cells (CSCs). Moreover, loss- and gain-of-functions of the stem cell genes SOX2, OCT4, and NANOG were investigated in the same cells. Single-cell clonal analysis was performed in vitro as well as in vivo. We found that no stable CSC subpopulation could be enriched in FPRMS. Unlike depletion of PAX3-FOXO1, neither overexpression nor siRNA-mediated downregulation of SOX2, OCT4, and NANOG affected physiology of RMS cells. Every single subclone-derived cell clone initiated tumor growth in mice, despite displaying considerable heterogeneity in gene expression. FPRMS appears to contain a high frequency of tumor propagating stem-like cells, which could explain their higher propensity for metastasis and relapse. Their dependency on PAX3-FOXO1 activity reinforces the importance of the fusion protein as the key therapeutic target.

Pericardial metastasis from alveolar rhabdomyosarcoma: A case report

Alveolar rhabdomyosarcoma (ARMS) commonly occurring in children and adolescents, is a rare and aggressive soft tissue malignancy demonstrating rapid growth and dissemination. Although their histopathologic and immunohistochemical findings are well known, cytomorphological features on serous effusions have not been well documented. A case of metastatic rhabdomyosarcoma diagnosed on cytological examination of the pericardial fluid cytology and discuss the diagnostic difficulties that were encountered in this case has been presented.

Embryonal rhabdomyosarcoma of breast, pleura, and retroperitoneum diagnosed from pleural fluid cytology

Embryonal rhabdomyosarcoma (ERMS) is a malignant small blue round cell tumor which is commonly seen in head and neck region. Breast and pleural involvement are uncommon. Rhabdomyosarcoma has been rarely reported in the body fluids like ascitic, pleural, and cerebrospinal fluid. In this article, we report an interesting case of ERMS which had deceptive small blue round cells in pleural fluid. The cytomorphological features along with a panel of immunocytochemical markers helped in arriving at the definite diagnosis. Later, biopsy from the breast lump and retroperitoneal mass also revealed the same tumor. This case is reported since it is rare to find sarcoma cells in pleural fluid and highlight the diagnostic difficulties faced during interpretation.

Adult parameningial alveolar rhabdomyosarcoma: Case report and literature review

Alveolar rhabdomyosarcoma (ARMS) represents the most common childhood soft tissue sarcoma, but they are rarely seen among adults. Most of the protocols for adults are adapted from pediatric protocols. Here we report a case of a 53-year-old woman diagnosed with a nasal alveolar rhabdomyosarcoma, stage IV at diagnosis, treated by chemotherapy (a regimen inspired from the pediatric protocole pEpSSG RMS 2005) which led to partial response followed by chemo-radiotherapy. We performed a systematic review of adult head and neck ARMS and found 29 cases. Primary chemotherapy with different protocols (VAC, VAI or VIE) should be done followed by surgery and/or external beam radiotherapy (preferably with IMRT). EBRT seems beneficial to every ARMS with a dose around 50Gy in a conventional fractionation, eventually completed with a boost on residual tumor. The target volume must be defined on pre-chemotherapy imaging. Brachytherapy and proton therapy are under evaluation.

Update on pediatric rhabdomyosarcoma: A report from the APSA Cancer Committee

BACKGROUND/PURPOSE

Rhabdomyosarcoma is the most common soft tissue sarcoma in children and young adults and requires multimodality treatment. The purpose of this review is to present an update on risk stratification as well as surgical and medical management strategies in pediatric rhabdomyosarcoma.

METHODS

A comprehensive review of the current literature on pediatric rhabdomyosarcoma, including the most recent Children's Oncology Group studies and several international collaboratives, was performed by the authors and key findings were summarized in the manuscript.

RESULTS

FOXO1 fusion status is a stronger prognostic factor than histology and is now used for risk stratification in treatment protocols. For assessment of regional nodal involvement, FDG-PET-CT shows poor sensitivity and specificity to detect histologically confirmed nodal metastasis. Thus, surgical assessment of regional lymph nodes is required for rhabdomyosarcoma of the extremities or trunk as well as paratesticular rhabdomyosarcoma in patients ≥10 years of age, although adherence to surgical guidelines remains poor. Hemiscrotectomy performed for scrotal violation in paratesticular rhabdomyosarcoma has not shown an improvement in event free survival and is not recommended.

CONCLUSIONS

Surgical and medical treatment strategies for rhabdomyosarcoma in children continue to evolve. This review provides current evidence-based treatment standards with an emphasis on surgical care.

TYPE OF STUDY

Review.

LEVEL OF EVIDENCE

Level IV.

Fine Needle Aspiration Cytology of Malignant Digestive System Gastrointestinal Neuroectodermal Tumor in a Lymph Node Metastasis from a Previously Diagnosed Liver Primary: A Case Report and Review of Literature

Malignant gastrointestinal neuroectodermal tumor (GNET) is an extremely rare neoplasm. Immunohistochemically, GNET typically demonstrates neural differentiation but lacks melanocytic differentiation, making it distinct from clear cell sarcoma of the soft tissues (CCS). Herein we report for the first time the cytomorphologic features of lymph node metastasis from presumably liver GNET. A 36-year-old female presented with fevers, night sweats, loss of appetite, and a 20-lbs weight loss. Radiographic imaging showed a 13 cm heterogeneously enhancing mass in the right lobe of the liver and a hypermetabolic 0.9 cm periportal lymph node on positron emission tomography-computed tomography (PET/CT). Initially, a CT-guided liver biopsy was performed followed by right hepatic lobectomy and portal lymphadenectomy. The liver biopsy and resection showed an S100-protein and SOX10 positive malignant neoplasm and genomic profiling of liver biopsy revealed EWSR1-CREB1gene rearrangement. These findings in conjunction with the morphologic and immunohistochemical profile were diagnostic of GNET. Two months later, she presented with recurrent lymphadenopathy in the upper abdomen. Fine needle aspiration of the periportal nodal mass revealed single and clusters of primitive, large to medium-sized neoplastic cells with round to oval nuclei, high nuclear-cytoplasmic ratio, vesicular chromatin, and prominent nucleoli. The tumor cells were S100 protein and SOX10 positive, consistent with metastasis of the patient's recently diagnosed malignant digestive system GNET. Palliative chemotherapy was administered but the patient died a few days later, 4 months from the initial diagnosis. Awareness of this entity and judicial use of ancillary studies including molecular testing are essential for achieving accurate diagnosis.

Embryonal mastoid rhabdomyosarcoma in a three years old child: A case report

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The middle ear is a very rare site for rhabdomyosarcoma in children.

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The common clinical presentation of middle ear rhabdomyosarcoma is suppurative chronic otitis media which might delay the diagnosis.

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Chemotherapy with loco-regional radiotherapy and surgery are the main therapeutic mainstay.

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Rhabdomyosarcoma should be considered as a differential diagnosis of any mastoiditis resistant to treatment in a young child.

Introduction

Rhabdomyosarcoma is the most common malignant soft tissue tumor in the pediatric age, especially in the head and neck region; in the orbit and the nasopharynx. The middle ear is a very rare site for this neoplasm as it accounts for only 10 % of head neck rhabdomyosarcoma.

Presentation of case

We report here the case of a three years-old child who was admitted to the emergency room for a left parotid and retro-auricular swelling with grade V facial palsy. The patient experienced chronic otorrhea with left facial palsy for two months. Two weeks later, a left parotid swelling appeared and gradually increased in size with weight loss. Computed tomography showed a slightly dense tissue lesion in the left mastoid. The patient underwent a diagnostic mastoidectomy. Pathology and immunohistochemical study were compatible with an embryonic rhabdomyosarcoma.

Conclusion

Rhabdomyosarcoma should be considered as a differential diagnosis of any mastoiditis resistant to treatment in a young child. Because of its serious prognosis, rhabdomyosarcoma must be diagnosed at an early stage to increase chances of recovery.

Should we keep rocking? Portraits from targeting Rho kinases in cancer

Cancer targeted therapy, either alone or in combination with conventional chemotherapy, could allow the survival of patients with neoplasms currently considered incurable. In recent years, the dysregulation of the Rho-associated coiled-coil kinases (ROCK1 and ROCK2) has been associated with increased metastasis and poorer patient survival in several tumor types, and due to their essential roles in regulating the cytoskeleton, have gained popularity and progressively been researched as targets for the development of novel anti-cancer drugs. Nevertheless, in a pediatric scenario, the influence of both isoforms on prognosis remains a controversial issue. In this review, we summarize the functions of ROCKs, compile their roles in human cancer and their value as prognostic factors in both, adult and pediatric cancer. Moreover, we provide the up-to-date advances on their pharmacological inhibition in pre-clinical models and clinical trials. Alternatively, we highlight and discuss detrimental effects of ROCK inhibition provoked not only by the action on off-targets, but most importantly, by pro-survival effects on cancer stem cells, dormant cells, and circulating tumor cells, along with cell-context or microenvironment-dependent contradictory responses. Together these drawbacks represent a risk for cancer cell dissemination and metastasis after anti-ROCK intervention, a caveat that should concern scientists and clinicians.

Recent Advances and Challenges in the Treatment of Rhabdomyosarcoma

Rhabdomyosarcoma, the most common soft tissue sarcoma noted in childhood, requires multimodality treatment, including chemotherapy, surgical resection, and/or radiation therapy. The majority of the patients with localized rhabdomyosarcoma can be cured; however, the long-term outcomes in patients with metastatic rhabdomyosarcoma remain poor. The standard chemotherapy regimen for patients with rhabdomyosarcoma is the combination of vincristine, actinomycin, and cyclophosphamide/ifosfamide. In recent clinical trials, modifications of the standard chemotherapy protocol have shown improvements in the outcomes in patients with rhabdomyosarcoma. In various type of malignancies, new treatments, such as molecular targeted drugs and immunotherapies, have shown superior clinical outcomes compared to those of standard treatments. Therefore, it is necessary to assess the benefits of these treatments in patients with rhabdomyosarcoma. Moreover, recent basic and clinical studies on rhabdomyosarcoma have reported promising therapeutic targets and novel therapeutic approaches. This article reviews the recent challenges and advances in the management of rhabdomyosarcoma.

The survival benefit of radiotherapy in localized primary adult rhabdomyosarcoma

AIM

To evaluate the role of radiotherapy (RT) in the treatment of localized primary adult rhabdomyosarcoma (RMS).

METHODS

This retrospective study identified 62 consecutive adult patients with localized primary RMS from January 2000 and July 2016. Local failure-free survival (LFFS), distant metastasis-free survival (DMFS) and overall survival (OS) were analyzed by the Kaplan-Meier method. Multivariate Cox proportional hazards regression models were fit to assess the ability of patient characteristics to predict survival.

RESULTS

With a median follow-up of 33 months (range, 6-195 months), the 5-year LFFS, DMFS and OS of all patients were 64.0%, 50.0% and 45.0%, respectively. RT was administered to 28 patients (45.2%). Patients who received RT had a higher 5-year LFFS (81.7% vs 47.2%), 5-year DMFS (59.4% vs 43.1%) and 5-year OS (57.1% vs 34.8%) compared with patients who did not received RT. In mulitvariate analysis, RT retained significance as an independent predictor of improved LFFS [hazard ratio (HR) = 0.282; 95% confidence interval (CI), 0.095-0.838; P = 0.023], DMFS (HR = 0.289; 95% CI, 0.125-0.991; P = 0.004) and OS (HR = 0.334; 95% CI, 0.153-0.727; P = 0.006).

CONCLUSIONS

RT significantly reduced local recurrence, distant metastasis and tumor mortality compared with no radiotherapy for localized primary adult RMS.

Chemopreventive Effects and Antioxidant Capacity of Combined Leaf Extracts of Sesamum angustifolium (Oliv.) Engl. and Hibiscus articulatus on Rhabdomyosarcoma

Sesamum angustifolium (Oliv.) Engl. and Hibiscus articulatus contain compounds that have antimutagenic properties. The rise in rhabdomyosarcoma in paediatrics and prognosis of the disease in infants compared to adults calls for newer, less toxic alternatives in treatment of the disease. The aim of this study was to determine the anticancer activity and antioxidant capacity of combined leaf extracts of Sesamum angustifolium (Oliv.) Engl. and Hibiscus articulatus (SAHA), against rhabdomyosarcoma (RMS) using rhabdomyosarcoma (RD) cell line and mouse (L20B) cell line. Cytotoxicity, morphology, apoptosis induction, and antioxidant capacity assays were done. Of the four solvents used for extraction, the dichloromethane SAHA extract was the most cytotoxic with IC₅₀ of 106 μg/mL after doxorubicin, the reference anticancer drug with IC₅₀ of 0.8 μg/mL. The SAHA extracts had a stronger cytotoxicity effect on the cancerous RD cells than on normal L20B cells. Morphological assessment showed untreated cells maintained their normal striated appearance of muscle cells whereas cells treated with doxorubicin or SAHA extracts exhibited cell shrinkage, loss of surface adherence, reduced cell density along with cell debris, which is a characteristic of apoptosis. Normal L20B cells when treated with doxorubicin or SAHA extracts, maintained their cell shape, and remained adherent to the surface. The apoptotic enzyme caspase-3 was induced in a concentration dependent manner upon treatment of the RD cells with SAHA extracts or doxorubicin. Induction of caspase-3 was ten times less in treated L20B cells compared to the RD cells. Low induction of caspase-9 enzyme was observed in both treated RD and L20B cells. Treatment of both RD and L20B cells with SAHA extracts or doxorubicin resulted in increased activity of peroxidase and reduction of oxidative stress. Results of the study show that the SAHA extracts are potential sources of compounds that may serve as useful agents for treatment of rhabdomyosarcoma.

Treatment strategies and outcomes for spinal rhabdomyosarcoma: A series of 11 cases in a single center and review of the literature

OBJECTIVES

Rhabdomyosarcoma (RMS) involving the spine is rare. The aim of the present study is to explore the clinicopathological features, surgical treatments and outcomes of this rare disease.

PATIENTS AND METHODS

Eleven patients with spinal RMS who received surgery in our institution between 2012 and 2018 were retrospectively investigated. The literature on spinal RMS was also reviewed.

RESULTS

Our study consisted of 7 cases of primary RMS and 4 cases of metastatic RMS. Seven primary and one metastatic spinal RMS received radical resection, the remaining three metastatic patients received palliative resection. Eight patients died with a median survival time of 8 months. The mean value of Ki-67 positivity was 48.2 %. Literature review revealed a total of 22 previously reported cases. 54.5 % of the pooled cases of the 33 patients were under the age of 18. Of the 20 patients with primary spinal RMS, 9 cases were diagnosed as embryonal, while 6 of the 13 metastatic patients were diagnosed as alveolar. Multiple modalities, including surgery and concurrent adjuvant therapy were performed in 19 patients. The median overall survival (OS) for 28 patients with detailed follow-up information was 10 months. Radical resection offered a significant longer median OS than non-radical resection (18 vs. 6 months, p = 0.027).

CONCLUSION

Spinal RMS mainly affects young patients. The embryonal form and alveolar form is the most frequent subtype for primary and metastatic spinal RMS respectively. Spinal RMS is highly aggressive with dismal prognosis. Multimodality therapies are the mainstay of treatment. Radical resection is strongly recommended in eligible patients.

Oropharyngeal Rhabdomyosarcoma with cranial nerve paralysis in a limited resource setting: a case report and review of literature

Rhabdomyosarcoma (RMS), a tumor of skeletal muscle origin, is the most common soft tissue sarcoma encountered in childhood and adolescence; it is primarily found in the head and neck region, it is relatively uncommon tumors of the oral cavity. Clinical signs depend on the exact location of the lesion in the oral cavity and its development. Authors reported the case of a 14-year-old patient who presented an oropharyngeal mass causing voice dysfunction, after two surgical operation the patient experimented two 2 recurrences of the lesion. The histopathological examination objectifies an oropharyngeal rhabdomyosarcoma. Immediate postoperative outcome was uneventful with improvement in the voice dysfunction and dysphagia one month after surgery. Complementary treatment (chemotherapy and radiotherapy) was not available and accessible to the patient. Twenty months (20) after surgery, the examination found a recurrence of the tumor with pulmonary metastases and neurological complications. Oropharyngeal rhabdomyosarcomas are rare. Their interest lies in the fact that they often affect children and adolescents. The prognosis remains unfavorable in our context, even for cases accessible to surgery since complementary treatment with chemotherapy and / or radiotherapy does not exist. The prognosis depends on tumor size, location, staging, age of patients and especially the quality of the management.

Inhibition of NR4A1 Promotes ROS Accumulation and IL24-Dependent Growth Arrest in Rhabdomyosarcoma

Nuclear receptor 4A1 (NR4A1, Nur77) is overexpressed in rhabdomyosarcoma (RMS), and inactivation of NR4A1 (siNR4A1) or treatment with the NR4A1 antagonist 1,1-bis(3'-indoly)-1-(p-hydroxy-phenyl)methane (DIM-C-pPhOH) has antiproliferative and proapoptotic effects on RMS cells. However, the mechanism by which NR4A1 inhibition exerts these effects is poorly defined. Here, we report that NR4A1 silencing or inhibition resulted in accumulation of reactive oxygen species (ROS) and ROS-dependent induction of the tumor suppressor-like cytokine IL24 in RMS cells. Mechanistically, NR4A1 was found to regulate the expression of the proreductant genes thioredoxin domain-containing 5 (TXNDC5) and isocitrate dehydrogenase 1 (IDH1), which are downregulated in RMS cells following NR4A1 knockdown or inhibition. Silencing TXNDC5 and IDH1 also induced ROS accumulation and IL24 expression in RMS cells, suggesting that NR4A1 antagonists mediate their antiproliferative and apoptotic effects through modulation of proreductant gene expression. Finally, cotreatment with the antioxidant glutathione or IL24-blocking antibody reversed the effects of NR4A1 inhibition, demonstrating the importance of both ROS and IL24 in mediating the cellular responses. IMPLICATIONS: Overall, these data elucidate the mechanism by which NR4A1 inhibition functions to inhibit the proliferation, survival, and migration of RMS cells.

Primary Rhabdomyosarcoma of the Breast: Study of Three Cases at One Institution with a Review of Primary Breast Sarcomas

BACKGROUND

Primary breast sarcoma (PBS) is rare, comprising approximately 1% of breast malignancies. Rhabdomyosarcoma (RMS) accounts for an extremely small proportion of PBSs, often leading to delayed histologic confirmation.

METHODS

Upon reviewing Asan Medical Center's pathology database between 2000 and 2018, 41 PBS cases were retrieved, including three cases of primary RMS of the breast. Their clinicopathological features were analyzed, and the literature related to PBS and primary RMS of the breast was reviewed.

RESULTS

We identified three primary breast RMS cases from our institution database, comprising 7.3% of PBS: one case each of spindle cell/sclerosing RMS (ssRMS), alveolar RMS (aRMS), and embryonal RMS (eRMS). All cases involved adolescents or young adults (14, 16, and 25 years, respectively) who underwent mastectomy or radiotherapy and were confirmed using immunohistochemical testing for myogenin, desmin, and myogenic differentiation. The ssRMS patient experienced recurrence at the operation site 4 months post-surgery despite undergoing concurrent chemoradiotherapy. The aRMS patient had multiple metastases at diagnosis and showed FAX3-FOXO1 fusion transcripts; she died 22 months after the diagnosis. The eRMS patient had enlarged axillary lymph nodes; post-radiotherapy, the lesion recurred as multiple metastases to the bone and lung. She died 18 months post-diagnosis.

CONCLUSIONS

Our experience on RMS cases suggests that spindle cell or small round cell malignancy in breasts of young female should raise suspicion for the possibility of primary or secondary RMS. To our knowledge, this is the second report of primary breast ssRMS and it may help clinicians who encounter this rare disease in the future.

Small bowel metastasis from pulmonary rhabdomyosarcoma causing intussusception: a case report

Background

Rhabdomyosarcoma (RMS), especially primary pulmonary RMS, is an extremely rare type of soft tissue sarcoma in adults. Small bowel is an uncommon site for metastases.

Case presentation

This report described an unusual case of jejunum metastasis from primary pulmonary RMS causing intussusception in a 75-year-old man. The patient consulted for 2 weeks of continuous dyspnea. Chest computed tomography (CT) demonstrated a large mass involving the left lower lobe. Transthoracic biopsy confirmed the existence of pleomorphic RMS. Immunohistochemical studies showed positive findings about desmin and MyoD1. The results of gastroscopy, colonoscopy and abdominal CT were all negative. Positron emission tomography/CT demonstrated a fluorodeoxyglucose-reactive large lesion in the left lower lobe without metastatic lesions. The patient received synchronous chemoradiotherapy. After 9 months, the patient presented with intermittent upper abdominal pain with nausea and vomiting. CT showed small bowel dilatation secondary to intussusception. The patient subsequently received laparotomy, and the intussuscepted small bowel segment was resected. Histological examination revealed pleomorphic RMS involving the mucosa, submucosa, and muscular tissues.

Conclusions

RMS is highly aggressive and metastatic. The metastatic disease can rapidly progress to cause subsequent complications. The possibility of small bowel metastasis should be considered, although it is extremely rare.

Primary Alveolar Rhabdomyosarcoma of the Breast in an Adult: An Extremely Rare Case

Sarcomas of the breast constitute less than 1% of all malignant breast tumors and primary rhabdomyosarcoma (RMS) is a very rare entity with limited case reports in the literature. RMS is common in children and adolescents and rare in adults. Primary RMS arising from the breast is exceedingly rare in adults. We report a case of a primary RMS of the breast in a 60-year-old woman, who presented in an early stage, mimicking invasive ductal carcinoma clinically and is in complete remission after three years of diagnosis and one year of treatment.

Primary alveolar rhabdomyosarcoma of retrorectal-presacral space in an adult patient: A case report of an uncommon tumor with rare presentation

RATIONALE

Rhabdomyosarcoma (RMS) has known as a highly malignant soft tissue sarcoma, representing 5% to 10% of all solid tumors in childhood. Alveolar rhabdomyosarcoma (ARMS) of the retrorectal-presacral space is an extremely rare lesion for adult, no study has been reported in the English literature.

PATIENT CONCERNS

A 51-year-old male presented with abdominal pain for 1 month, significantly worse when having a bowel movement.

DIAGNOSIS

Computed tomography (CT) and magnetic resonance imaging (MRI) of the pelvis showed a solid-cystic, enhancing lesion of dimension located in retrorectal-presacral space. The surgical specimen was reported as ARMS after pathological evaluation.

INTERVENTIONS

The tumor was complete surgical resection, and after surgery, the patient was treated with combination chemotherapy.

OUTCOMES

At 23 months follow up, the patient was asymptomatic with no evidence of metastases or local recurrence.

LESSONS

Improvements in imaging in addition to early surgical intervention and chemotherapy treatment are crucial to improve survival chances against RMS.

Embryonal rhabdomyosarcoma within abdomen and pelvis in an adult

Rhabdomyosarcoma arising in abdomen and pelvis is an uncommon but important type of soft tissue sarcoma, posing a great challenge for clinicians. Sporadic cases of intra-abdominal rhabdomyosarcoma were reported, but mostly in pediatrics. We demonstrated a rare case of primary abdominopelvic rhabdomyosarcoma in an elderly woman who presented with a notable increase in abdominal circumference and constipation. Abdominal magnetic resonance imaging showed a huge mass throughout the abdomen and pelvis. Cytoreductive surgery was performed by gynecologists due to the suspicious diagnosis of disseminated leiomyosarcoma. However, the final pathological analysis revealed embryonal rhabdomyosarcoma. Although adjuvant chemotherapy was administered, localized recurrence was identified 6 months after the initial operation. Gynecologists and radiologists should be aware of it so it can be listed in the differential diagnosis of masses that primarily arise in the abdomen and pelvis.

Interleukin-24 (IL24) Is Suppressed by PAX3-FOXO1 and Is a Novel Therapy for Rhabdomyosarcoma

Alveolar rhabdomyosarcoma (ARMS) patients have a poor prognosis, and this is primarily due to overexpression of the oncogenic fusion protein PAX3-FOXO1. Results of RNA-sequencing studies show that PAX3-FOXO1 represses expression of interleukin-24 (IL24), and these two genes are inversely expressed in patient tumors. PAX3-FOXO1 also regulates histone deacetylase 5 (HDAC5) in ARMS cells, and results of RNA interference studies confirmed that PAX3-FOXO1-mediated repression of IL24 is HDAC5-dependent. Knockdown of PAX3-FOXO1 decreases ARMS cell proliferation, survival, and migration, and we also observed similar responses in cells after overexpression of IL24, consistent with results reported for this tumor suppressor-like cytokine in other solid tumors. We also observed in double knockdown studies that the inhibition of ARMS cell proliferation, survival, and migration after knockdown of PAX3-FOXO1 was significantly (>75%) reversed by knockdown of IL24. Adenoviral-expressed IL24 was directly injected into ARMS tumors in athymic nude mice, and this resulted in decreased tumor growth and weight. Because adenoviral IL24 has already successfully undergone phase I in clinical trials, this represents an alternative approach (alone and/or combination) for treating ARMS patients who currently undergo cytotoxic drug therapies.

Clinicopathologic features of 300 rhabdomyosarcomas with emphasis upon differential expression of skeletal muscle specific markers in the various subtypes: A single institutional experience

The present study was aimed at evaluating clinicopathologic and immunohistochemical (IHC) features of 300 rhabdomyosarcomas (RMSs), including differential IHC expression and prognostic value of myogenin and MyoD1 across various subtypes of RMSs. IHC expression of myogenin and MyoD1 was graded on the basis of percentage of tumor cells displaying positive intranuclear immunostaining i.e. grade 1 (1-25%); grade 2 (26-50%); grade 3 (51-76%) and grade 4 (76-100%).Clinical follow-up was available in 238 (79.3%) patients. Various clinicopathologic parameters were correlated with 3-year disease free survival (DFS) and overall survival (OS). There were 140 cases (46.7%) of alveolar RMS (ARMS), 90 of embryonal RMS (ERMS) (30%), 61 (20.3%) of spindle cell/sclerosing RMS and 9 cases (3%) of pleomorphic RMS. Most cases, barring pleomorphic RMSs, occurred in the first two decades (228 cases) (76%), frequently in males, in the head and neck region (126) (42%). By immunohistochemistry, desmin was positive in 292/299 (97.6%) tumors; myogenin in 238/267 (89.1%) and MyoD1 in 192/266 (72.2%) tumors. High myogenin expression (in ≥51% positive tumor cells) was significantly associated with ARMSs (95/121, 78.5%), as compared to other subtypes (48/117, 41%) (p value < 0.001). High MyoD1 expression (≥51% tumor cells) was seen in more cases of pure sclerosing, combined with spindle cell/sclerosing RMSs (10/10, 100%), as compared to the other subtypes (91/141, 67.4%) (p = 0.032). There was no significant difference between high myogenin expression and clinical outcomes. Patients without metastasis and harbouring tumors, measuring ≤5 cm showed a significant increase in OS, with p values = 0.01 and <0.001, respectively. ARMS was the most frequent subtype. There was a significant association between high myogenin expression and ARMSs and high MyoD1 expression and spindle cell/sclerosing RMSs. High myogenin expression did not correlate with clinical outcomes. Patients with smaller sized tumors and without metastasis had significantly better clinical outcomes.

Safety markers for rhabdomyosarcoma cells using an in vivo imaging system

In vivo imaging system (IVIS) is a novel and rapidly expanding technology that is widely applied in life sciences, including cell tracing. IVIS is able to quantify biological events, including tumor proliferation, through counting the number of photons emitted from a specimen. PLA802-enhanced green fluorescent protein (EGFP), PLA802-monomeric cherry fluorescent protein (mCherry), RH30-EGFP and RH30-mCherry tumor cells were injected into 18 BALB/c female nude mice subcutaneously with 5×10⁶ cells in 100 µl to quantitatively analyze EGFP and mCherry cells traced by IVIS. Inversion fluorescence microscopy revealed no transfection efficiency difference between PLA802-EGFP (95.3±1.2%) and PLA802-mCherry (95.8±1.7%), or between RH30-EGFP (94.7±2.1%) and RH30-mCherry (95.2±1.9%). Transfection did not influence the cell morphology of PLA802 or RH30. The cell migration, invasion and proliferation assay results of lentivirus-EGFP and lentivirus-mCherry revealed no significant difference prior to or following transfection. Therefore, lentivirus-EGFP and lentivirus-mCherry may serve as safety biological markers for PLA802 and RH30 cells. In vivo experiments demonstrated that lentivirus-EGFP and lentivirus-mCherry tumor luminescence signals were observed in all mice by IVIS. Hematoxylin-eosin staining and immunohistochemistry indicated that PLA802-EGFP, PLA802-mCherry, RH30-EGFP and RH30-mCherry cell lines exhibited rhabdomyosarcoma (RMS) characteristics like the maternal cells. In summary, mCherry and green fluorescent protein in human RMS PLA802 and RH30 cancer cells may be safely and stably expressed for a long time in vitro and in vivo.