Rhabdomyosarcoma in adolescent and young adult patients: current perspectives

A rare case of perianal alveolar rhabdomyosarcoma

Perianal alveolar rhabdomyosarcoma is a rare sarcoma that requires a high index of suspicion along with tissue biopsy for accurate diagnosis. Successful treatment, even in the setting of recurrence, requires a multidisciplinary approach.

A rare case of metastatic paraspinal rhabdomyosarcoma presenting with proptosis in an adult patient

Secondary metastasis of rhabdomyosarcoma (RMS) to the orbit from a distant primary site is extremely rare in adults. In this article, we describe the case of a 24-year-old male presenting with proptosis, diplopia, and headaches concurrently with a histologically confirmed diagnosis of PAX3-FOXO1 positive paraspinal alveolar rhabdomyosarcoma. An orbital MRI revealed a fusiform mass arising from the inferior rectrus, displaying necrotic and irregular morphology consistent with malignancy. The patient is currently undergoing intensive chemotherapy. The objective of this case report is to highlight the rarity of an extraocular metastasis of RMS in an adult patient, alongside the importance of considering metastatic disease in a patient with fulminant unilateral proptosis.

Embryonal Rhabdomyosarcoma of the Prostate: Clinico-Pathological Highlights with Review of Literature

Rhabdomyosarcoma (RMS) is the third most common extra-cranial sarcoma occurring in childhood, adolescents, and young adults (AYAs); and is rare in adults. Literature about RMS mainly considers RMS in AYAs, either with that in the children or adults, even though histological, molecular, and clinical characteristics of RMS in AYAs are significantly different from either of the two. Herein, we report a case of prostatic embryonal RMS, in a 17-year-old boy, along with the review of literature of prostatic RMS, with emphasis on AYAs. Our patient presented with clinical complaints of acute urinary retention, Grade IV prostatomegaly and, low serum prostate-specific-antigen (0.11ng/dl). The diagnosis was clinched by prostatic biopsy, which revealed diffuse 'small round blue cell' tumour admixed with larger rhabdomyoblasts, displaying positivity for desmin and myogenin, on immunohistochemistry. Clinicians should be mindful that RMS is found in all age groups ranging from childhood to adults; however, the clinical, histological, and molecular features are different. RMS in AYAs is often treated according to the guidelines provided for the paediatric age group. Treatment mostly comprises a multimodality approach, including surgery with/without chemo- and radiotherapy. Prognosis in AYAs is worse than in children but is better than in adults. Thus, early diagnosis gains utmost importance to provide comparatively more probability of rendering treatment and, hopefully, a better quality of life.

Small bowel metastasis from embryonal rhabdomyosarcoma of the extremity- a case report

Rhabdomyosarcoma is the most common soft tissue tumour in children and adolescents, but extremely rare in adults with comparatively worse outcomes. Metastatic disease is not uncommon, but intra-abdominal metastases are exceedingly rare. We report an unusual case of ileal metastases from an upper extremity rhabdomyosarcoma in a 17-year-old male who presented with abdominal pain during a routine follow-up visit. Laparotomy and ileocecectomy for a perforated ileal mass confirmed metastatic embryonal rhabdomyosarcoma with 1 out of 14 positive lymph node metastases. This case demonstrates that, although rare, intra-abdominal metastases should be considered when patients with a rhabdomyosarcoma present with abdominal complaints.

ErbB2 (HER2)-CAR-NK-92 cells for enhanced immunotherapy of metastatic fusion-driven alveolar rhabdomyosarcoma

Introduction

Metastatic rhabdomyosarcoma (RMS) is a challenging tumor entity that evades conventional treatments and endogenous antitumor immune responses, highlighting the need for novel therapeutic strategies. Applying chimeric antigen receptor (CAR) technology to natural killer (NK) cells may offer safe, effective, and affordable therapies that enhance cancer immune surveillance.

Methods

Here, we assess the efficacy of clinically usable CAR-engineered NK cell line NK-92/5.28.z against ErbB2-positive RMS in vitro and in a metastatic xenograft mouse model.

Results

Our results show that NK-92/5.28.z cells effectively kill RMS cells in vitro and significantly prolong survival and inhibit tumor progression in mice. The persistence of NK-92/5.28.z cells at tumor sites demonstrates efficient antitumor response, which could help overcome current obstacles in the treatment of solid tumors.

Discussion

These findings encourage further development of NK-92/5.28.z cells as off-the-shelf immunotherapy for the treatment of metastatic RMS.

Orbital rhabdomyosarcoma in a 19-year-old male patient: A case report and literature review

Rhabdomyosarcoma (RMS) is the most common mesenchymal tumor in children and adolescents, with 10% of cases occurring in the orbits. RMS should be suspected whenever children present with rapidly progressing unilateral exophthalmos. Its symptoms depend on the lesion's origin and location. We report the clinical case of a 19-year-old male patient admitted to the hospital because of blurred vision and bulging eyes that gradually increased over several months. Magnetic resonance imaging showed a mass located mainly in the left orbit, pushing and deforming but not invading the eyeball. The lesion had grown into the left ethmoid sinus wall. The histopathological incisional biopsy results were with alveolar RMS.

Case report: Clinical features and prognosis of two Infants with rhabdomyosarcoma of the tongue

Background

Rhabdomyosarcoma (RMS) is the most common soft tissue tumor in children, and its most common pathological types include embryonal RMS and alveolar RMS. In contrast, spindle cell RMS (SRMS) is a rare type. Moreover, the tongue is a rare primary site of RMS, and infancy is a rare age at onset.

Case presentation

Two infants were diagnosed with lingual RMS at 3 and 5 months after birth, respectively, and were admitted to Beijing Children's Hospital. The pathological type in both cases was SRMS. Both were classified as low-risk and were treated with surgery and chemotherapy. Case 1 was in complete remission at the latest follow-up, and Case 2 had a relapse 10 months after stopping chemotherapy, achieving complete remission after the multimodal treatment of chemotherapy, surgery, and radiotherapy. The venous blood gene test of the two infants did not indicate a pathogenic mutation or a possible pathogenic mutation related to RMS. In Case 1, variants of the CDK4 and BRCA1 genes, both with unknown significance and a possible relation to RMS, were detected. In Case 2, three gene variants of unknown significance that were possibly associated with RMS-TRIP13, APC, and RAD54L-were identified.

Conclusion

Lingual RMS in infants is rare. Its clinical manifestations lack specificity, and early recognition is complex. The success and timing of local treatment are important prognostic factors. Genetic testing may be helpful for the early detection of tumor susceptibility and the estimation of prognosis.

Ferroptosis and its role in skeletal muscle diseases

Ferroptosis is characterized by the accumulation of iron and lipid peroxidation products, which regulates physiological and pathological processes in numerous organs and tissues. A growing body of research suggests that ferroptosis is a key causative factor in a variety of skeletal muscle diseases, including sarcopenia, rhabdomyolysis, rhabdomyosarcoma, and exhaustive exercise-induced fatigue. However, the relationship between ferroptosis and various skeletal muscle diseases has not been investigated systematically. This review’s objective is to provide a comprehensive summary of the mechanisms and signaling factors that regulate ferroptosis, including lipid peroxidation, iron/heme, amino acid metabolism, and autophagy. In addition, we tease out the role of ferroptosis in the progression of different skeletal muscle diseases and ferroptosis as a potential target for the treatment of multiple skeletal muscle diseases. This review can provide valuable reference for the research on the pathogenesis of skeletal muscle diseases, as well as for clinical prevention and treatment.

Particle beam radiation therapy for head and neck rhabdomyosarcoma in adults

Background

Rhabdomyosarcoma (RMS) is rare in adults, with a significantly worse prognosis than its pediatric counterpart. Radiotherapy (RT) plays a significant role in treating head and neck RMS (HNRMS), but the outcomes of conventional RT are limited by the complex anatomy and unfavorable pathology subtypes of the adult H&N RMS. Here, we aim to report the effectiveness and safety of carbon-ion beam RT (CIRT), either alone or in combination with proton radiotherapy (PRT) in the management of adult HNRMS.

Methods

Fifteen adult patients with HNRMS were enrolled on a prospective registry protocol between 06/2015 and 12/2019. Eight patients presented with parameningeal tumors, and eight had unfavorable pathology subtypes [alveolar =7, not otherwise specified (NOS) =1]. Eleven patients had gross tumors before the start of RT (volume range, 46.1-137.6 cm³). Two patients failed the earlier RT. All except for one patient received multi-drug chemotherapy. The median absolute dose of particle beam RT was 70.0 Gy [relative biological effectiveness (RBE)].

Results

With a median follow-up of 21 months, local or distant recurrence occurred in three and four patients, respectively, and two added patients had both local and distant failure. One patient died of distant metastasis (DM), and another died of an unrelated condition. The 1- and 2-year overall survival (OS), local relapse-free survival (LRFS), distant metastasis-free survival (DMFS), and progression-free survival (PFS) rates were 87.5% and 70.0%, 92.3% and 67.1%, 72.2% and 54.2%, and 65.0% and 24.4%, respectively, for the entire cohort. Both patients who failed earlier RT and received salvage CIRT developed DM but were alive at last follow-up. No acute toxicity of ≥ grade 3 or late toxicity of ≥ grade 2 was observed.

Conclusions

CIRT, either used alone or in combination with PRT, is not only feasible and safe but also useful in local disease control for HNRMS. DM is the most important cause of treatment failure; thus, more effective systemic treatment is needed to improve the prognosis of HNRMS further.

Prognostic factors of pediatric pelvic and genitourinary rhabdomyosarcoma: An analysis based on SEER database

Background

Rhabdomyosarcoma (RMS) is the most common soft-tissue sarcomas in children. This study aimed to investigate the prognostic factors of pelvic and genitourinary RMS in children and evaluate the survival outcomes of these children treated with or without radiation therapy (RT).

Methods

The Surveillance, Epidemiology, and End Results Program (SEER) database was required for children with pelvic and genitourinary RMS. Overall survival (OS) and cancer-specific survival (CSS) were analyzed using the Kaplan-Meier method, log-rank test, Cox proportional hazards models, and propensity score-matched analyses.

Results

For the 262 patients analyzed, the most common biological subtypes were embryonic (n=209, 79.8%) and alveolar (n=29, 11.1%). Patients with alveolar RMS had the worst prognosis (P < 0.05). The testis (n=122, 46.6%) was the most common location, followed by the urinary bladder (n=57, 21.8%) and prostate (n=48, 18.3%). Uterus RMS had the highest survival rate, followed by testis, urinary bladder, and prostate RMS. Favorable prognostic factors were age at diagnosis < 15 years, non-alveolar histological subtype, early tumor stage (localized/regional), specific sites (uterus and testis), and treatment (cancer-directed surgery and chemotherapy) (P < 0.05). Propensity score-matched analyses comparing the cohorts of patients treated with or without RT demonstrated no significant differences in prognostic survival (OS: P=0.872, CSS: P=0.713).

Conclusion

The nomogram constructed based on independent prognostic factors may accurately predict survival rates at 1 and 5 years. Surgery and adjuvant chemotherapy can be effective treatments, but RT fails to guarantee a survival benefit. Therefore, prospective trials evaluating RT for pediatric pelvic and genitourinary RMS are warranted.

Non-coding RNA in rhabdomyosarcoma progression and metastasis

Rhabdomyosarcoma (RMS) is a soft tissue sarcoma of skeletal muscle differentiation, with a predominant occurrence in children and adolescents. One of the major challenges facing treatment success is the presence of metastatic disease at the time of diagnosis, commonly associated with the more aggressive fusion-positive subtype. Non-coding RNA (ncRNA) can regulate gene transcription and translation, and their dysregulation has been associated with cancer development and progression. MicroRNA (miRNA) are short non-coding nucleic acid sequences involved in the regulation of gene expression that act by targeting messenger RNA (mRNA), and their aberrant expression has been associated with both RMS initiation and progression. Other ncRNA including long non-coding RNA (lncRNA), circular RNA (circRNA) and ribosomal RNA (rRNA) have also been associated with RMS revealing important mechanistic roles in RMS biology, but these studies are still limited and require further investigation. In this review, we discuss the established roles of ncRNA in RMS differentiation, growth and progression, highlighting their potential use in RMS prognosis, as therapeutic agents or as targets of treatment.

Precision Medicine Highlights Dysregulation of the CDK4/6 Cell Cycle Regulatory Pathway in Pediatric, Adolescents and Young Adult Sarcomas

Simple Summary

This review provides an overview of clinical features and current therapies in children, adolescents, and young adults (AYA) with sarcoma. It highlights the basic and clinical findings on the cyclin-dependent kinases 4 and 6 (CDK4/6) cell cycle regulatory pathway in the context of the precision medicine-based molecular profiles of the three most common types of pediatric and AYA sarcomas—osteosarcoma (OS), rhabdomyosarcoma (RMS), and Ewing sarcoma (EWS).

Abstract

Despite improved therapeutic and clinical outcomes for patients with localized diseases, outcomes for pediatric and AYA sarcoma patients with high-grade or aggressive disease are still relatively poor. With advancements in next generation sequencing (NGS), precision medicine now provides a strategy to improve outcomes in patients with aggressive disease by identifying biomarkers of therapeutic sensitivity or resistance. The integration of NGS into clinical decision making not only increases the accuracy of diagnosis and prognosis, but also has the potential to identify effective and less toxic therapies for pediatric and AYA sarcomas. Genome and transcriptome profiling have detected dysregulation of the CDK4/6 cell cycle regulatory pathway in subpopulations of pediatric and AYA OS, RMS, and EWS. In these patients, the inhibition of CDK4/6 represents a promising precision medicine-guided therapy. There is a critical need, however, to identify novel and promising combination therapies to fight the development of resistance to CDK4/6 inhibition. In this review, we offer rationale and perspective on the promise and challenges of this therapeutic approach.

Emerging Roles of Circ-ZNF609 in Multiple Human Diseases

Circular RNAs (circRNAs) are a special type of endogenous RNAs with extensive roles in multiple human diseases. They are formed by back-splicing of partial sequences of the parental precursor mRNAs. Unlike linear RNAs, their covalently closed loop structure without a 5′ cap and a 3′ polyadenylated tail confers on them high stability and they are difficult to be digested by RNase R. Increasing evidence has proved that aberrant expressions of many circRNAs are detected and that circRNAs exert essential biological functions in disease development and progression via acting as a molecular sponge of microRNA, interacting with proteins as decoys or scaffolds, or self-encoding small peptides. Circular RNA zinc finger protein 609 (circ-ZNF609) originates from exon2 of ZNF609, which is located at chromosome 15q22.31, and it has recently been proved that it can translate into a protein. Being aberrantly upregulated in various diseases, it could promote malignant progression of human tumors, as well as tumor cell proliferation, migration, and invasion. Here in this review, we concluded the biological functions and potential mechanisms of circ-ZNF609 in multiple diseases, which could be further explored as a targetable molecule in future accurate diagnosis and prognosis.

Adult Sinonasal Rhabdomyosarcoma With Spinal Metastasis: A Case Report and Review of the Literature

Rhabdomyosarcoma (RMS) is a malignant soft-tissue tumor mainly seen in the pediatric population. Here, we describe a case of an aggressive sinonasal RMS with distant metastasis in an adult patient. A 51-year-old male presented to the otolaryngology clinic with a unilateral painless neck mass and nasal obstruction. A flexible transnasal endoscope showed a huge fungating mass obstructing more than 80% of the right nasal cavity. A contrasted computed tomography (CT) scan of the paranasal sinuses showed an enhancing soft-tissue density mass involving the right nasal cavity. A biopsy revealed RMS, an embryonal variant. The patient responded well to chemoradiotherapy but later developed spinal metastasis and cord compression. He was admitted for palliative care but died due to cardiopulmonary arrest 10 months after diagnosis. A high index of clinical suspicion for malignancy is required in adult patients with unilateral nasal symptoms.

MEK and MCL-1 sequential inhibition synergize to enhance rhabdomyosarcoma treatment

Targeted agents have emerged as promising molecules for cancer treatment, but most of them fail to achieve complete tumor regression or attain durable remissions due to tumor adaptations. We used dynamic BH3 profiling to identify targeted agents effectiveness and anti-apoptotic adaptations upon targeted treatment in rhabdomyosarcoma. We focused on studying the use of BH3 mimetics to specifically inhibit pro-survival BCL-2 family proteins, overwhelm resistance to therapy and prevent relapse. We observed that the MEK1/2 inhibitor trametinib rapidly depleted the pro-apoptotic protein NOXA, thus increasing MCL-1 availability. Indeed, we found that the MCL-1 inhibitor S63845 synergistically enhanced trametinib cytotoxicity in rhabdomyosarcoma cells in vitro and in vivo. In conclusion, our findings indicate that the combination of a BH3 mimetic targeting MCL-1 with trametinib improves efficiency on rhabdomyosarcoma by blocking tumor adaptation to treatment.

Gross perianal embryonal rhabdomyosarcoma with severe multiple bone metastases throughout the body: a case report

In adults, embryonal rhabdomyosarcoma (ERMS) is rare and has a poor prognosis. Giant perianal ERMS with severe multiple bone metastases at initial diagnosis has not been reported and lacks effective treatment options. This current case report describes a 31-year-old female patient that presented with a large lump on the right side of the anus. ERMS was diagnosed, accompanied by multiple bone metastases throughout the body and severe thrombocytopenia. She had an extremely low platelet count at initial diagnosis, making systemic chemotherapy inappropriate. Genetic testing did not help identify effective targeted drugs. A multi-target tyrosine kinase inhibitor, anlotinib, was selected to control the tumours combined with local radiotherapy to relieve pain. The lump became smaller and this reduction was maintained for 5 months. At 7 months after the diagnosis, the patient died of thrombocytopenia. This current case may provide supportive evidence for a potential treatment for patients with advanced ERMS, especially those not suitable for chemotherapy or surgery.

Bioinformatics prediction and experimental verification identify MAD2L1 and CCNB2 as diagnostic biomarkers of rhabdomyosarcoma

Background

Rhabdomyosarcoma (RMS) is a malignant soft-tissue tumour. In recent years, the tumour microenvironment (TME) has been reported to be associated with the development of tumours. However, the relationship between the occurrence and development of RMS and TME is unclear. The purpose of this study is to identify potential tumor microenvironment-related biomarkers in rhabdomyosarcoma and analyze their molecular mechanisms, diagnostic and prognostic significance.

Methods

We first applied bioinformatics method to analyse the tumour samples of 125 patients with rhabdomyosarcoma (RMS) from the Gene Expression Omnibus database (GEO). Differential genes (DEGs) that significantly correlate with TME and the clinical staging of tumors were extracted. Immunohistochemistry (IHC) was applied to validate the expression of mitotic arrest deficient 2 like 1 (MAD2L1) and cyclin B2 (CCNB2) in RMS tissue. Then, we used cell function and molecular biology techniques to study the influence of MAD2L1 and CCNB2 expression levels on the progression of RMS.

Results

Bioinformatics results show that the RMS TME key genes were screened, and a TME-related tumour clinical staging model was constructed. The top 10 hub genes were screened through the establishment of a protein–protein interaction (PPI) network, and then Gene Expression Profiling Interactive Analysis (GEPIA) was conducted to measure the overall survival (OS) of the 10 hub genes in the sarcoma cases in The Cancer Genome Atlas (TCGA). Six DEGs of statistical significance were acquired. The relationship between these six differential genes and the clinical stage of RMS was analysed. Further analysis revealed that the OS of RMS patients with high expression of MAD2L1 and CCNB2 was worse and the expression of MAD2L1 and CCNB2 was related to the clinical stage of RMS patients. Gene set enrichment analysis (GSEA) revealed that the genes in MAD2L1 and CCNB2 groups with high expression were mainly related to the mechanism of tumour metastasis and recurrence. In the low-expression MAD2L1 and CCNB2 groups, the genes were enriched in the metabolic and immune pathways. Immunohistochemical results also confirmed that the expression levels of MAD2L1 (30/33, 87.5%) and CCNB2 (33/33, 100%) were remarkably higher in RMS group than in normal control group (0/11, 0%). Moreover, the expression of CCNB2 was related to tumour size. Downregulation of MAD2L1 and CCNB2 suppressed the growth, invasion, migration, and cell cycling of RMS cells and promoted their apoptosis. The CIBERSORT immune cell fraction analysis indicated that the expression levels of MAD2L1 and CCNB2 affected the immune status in the TME.

Conclusions

The expression levels of MAD2L1 and CCNB2 are potential indicators of TME status changes in RMS, which may help guide the prognosis of patients with RMS and the clinical staging of tumours.

Dissecting the Role of Circular RNAs in Sarcomas with Emphasis on Osteosarcomas

Circular RNAs (circRNAs) are single-stranded RNAs generated from exons back-splicing from a single pre-mRNA, forming covalently closed loop structures which lack 5'-3'-polarity or polyadenylated tail. Ongoing research depicts that circRNAs play a pivotal role in tumorigenesis, tumor progression, metastatic potential and chemoresistance by regulating transcription, microRNA (miRNA) sponging, RNA-binding protein interactions, alternative splicing and to a lesser degree, protein coding. Sarcomas are rare malignant tumors stemming from mesenchymal cells. Due to their clinically insidious onset, they often present at advanced stage and their treatment may require aggressive chemotherapeutic or surgical options. This review is mainly focused on the regulatory functions of circRNAs on osteosarcoma progression and their potential role as biomarkers, an area which has prompted lately extensive research. The attributed oncogenic role of circRNAs on other mesenchymal tumors such as Kaposi Sarcoma (KS), Rhabdomyosarcoma (RMS) or Gastrointestinal Stromal Tumors (GISTs) is also described. The involvement of circRNAs on sarcoma oncogenesis and relevant emerging diagnostic, prognostic and therapeutic applications are expected to gain more research interest in the future.

Clinical features and prognosis of paediatric rhabdomyosarcoma with bone marrow metastasis: a single Centre experiences in China

BACKGROUND

The aim of this study was to summarize the clinical characteristics, therapeutic effects and prognosis of patients with rhabdomyosarcoma (RMS) and bone marrow metastasis, improve the understanding of this disease.

METHOD

This was a single-institution retrospective study involving the children with RMS, who presented with bone marrow metastasis at initial presentation to our hospital between 1st, Jan, 2006 and 31st, Dec,2019. Follow-up concluded on 31st, Dec, 2020 and the clinical data were collected and analysed.

RESULT

Between 1st Jan 2006 and 31st Dec 2019, 13 eligible patients presented to our hospital, including 10 males and 3 females, these eligible patients accounted for 4.5% of all RMS patients. The median age at onset was 5.6 years (range 1.7-14 years). The patients not only had unfavourable primary sites, but also had multiple metastases. The bone marrow aspirate samples of the patients comprised 8-95% blast-like cells. Nine of 13 patients were misdiagnosed with haematological malignancies or other solid tumours. With respect to histology, four of 13 children were classified as embryonal RMS and nine as alveolar RMS. Eleven patients underwent PAX-FOXO1 fusion testing; eight had the POX- FOXO1 fusion gene. Immunohistochemically(IHC) analysis revealed that the tumour cells were positive for Desmin, Vimentin, Myo-D1 and Myogenin. More importantly, the patients had extremely poor prognoses, the median EFS was 12.0 months (range 3-28.3 months) and the median OS was 27.0 months (range6-46.2 months).

CONCLUSION

This study demonstrates that children with RMS and bone marrow metastasis usually exhibit atypical primary sites and multiple metastases, with presentation mimicking haematological malignancies or other solid tumors at initial presentation. Pathology and IHC analysis combined with POX-FOXO1 fusion gene detections can effectively confirm the diagnosis. These patients are more likely to relapse or progress during early treatment and are prone to intracranial metastasis. While multidisciplinary therapy combined with Temozolomide may prevent it, further prospective research is required to evaluate the therapeutic effects.

Extremities Soft Tissue Sarcomas, more Common and as Dangerous as Bone Sarcomas

Musculoskeletal sarcomas are rare diseases that require attention. They often present high degree of malignancy at diagnosis and, if underestimated, they can evolve aggressively locally and systemically. They present as soft tissue sarcoma and bone sarcomas, with soft tissue being four to five times more common. Most soft tissue sarcomas occur in the extremities. The most common subtypes in children and adolescents are rhabdomyosarcoma and synovial sarcoma; in adults, undifferentiated pleomorphic sarcoma, liposarcoma, leiomyosarcoma, myxofibrosarcoma and synovial sarcoma; all with a high degree of histological malignancy. Many soft tissue sarcomas are confused with benign soft tissue tumors, 100 times more common, so they are resected without the necessary planning, resulting in amputation of a limb that could have been preserved. As in all cancers, the most important prognostic factor is metastatic disease. When it is present, the overall survival rate falls around 20 to 30%. Survival rates are generally similar between bone and soft tissue sarcomas. So soft tissue sarcomas, in addition to being more prevalent, are as aggressive as bone sarcomas, deserving a lot of attention from orthopedic surgeons, who are often the first line of care of carriers of these tumors.

Rare Adult Subtype of Rhabdomyosarcoma, a Common Childhood Soft Tissue Carcinoma

Rhabdomyosarcoma is a malignant soft tissue sarcoma of primitive mesenchymal cells, showing varying degrees of striated skeletal muscle cell differentiation. It is a very common cancer of childhood and adolescence, but rarely seen in the adult population. Here, we present a case of a 33-year-old male presented with a poorly differentiated desmin positive alveolar rhabdomyosarcoma in the left arm. The prognosis of alveolar rhabdomyosarcoma in adults is very poor, frequently detected at advanced stages or with metastases. The alveolar subtype in particular has been found to have a more aggressive course with a high rate of metastasis. Recent studies have shown that using pediatric treatment guidelines resulted in better survival outcomes and local control, but the survival rates are still below that of the pediatric population. Newer studies are looking into using specific molecular markers for more targeted therapy in hopes of further improving survival rates in the adult population.

CircVAMP3: A circRNA with a Role in Alveolar Rhabdomyosarcoma Cell Cycle Progression

Circular RNAs (circRNAs), a class of covalently closed RNAs formed by a back-splicing reaction, have been involved in the regulation of diverse oncogenic processes. In this article we describe circVAMP3, a novel circular RNA overexpressed in RH4, a representative cell line of alveolar rhabdomyosarcoma. We demonstrated that circVAMP3 has a differential m⁶A pattern opposed to its linear counterpart, suggesting that the two isoforms can be differently regulated by such RNA modification. Moreover, we show how circVAMP3 depletion in alveolar rhabdomyosarcoma cells can impair cell cycle progression, through the alteration of the AKT-related pathways, pointing to this non-coding RNA as a novel regulator of the alveolar rhabdomyosarcoma progression and as a putative future therapeutic target.

Embryonal Rhabdomyosarcoma of Prostate in Adult: A Rare Case Report

Rhabdomyosarcoma is the fifth most common type of soft tissue solid tumor in children and the most common in the last two decades. Rhabdomyosarcoma of the urogenital organ is a rare mesenchymal tumor, covering 22% of all Rhabdomyosarcoma cases. The two most common histologic types are alveolar and embryonal, whereas botryoid and spindle cells are rarely found. We reported a case of embryonal Rhabdomyosarcoma of the prostate. In this study, we improved the understanding of Embryonal Rhabdomyosarcoma of the prostate on 23 years old male who had a history of swelling in the perineal area and a history of falling from a height in the groin area 5 months before. The patient complains of the difficulty of urinating and hematuria one month after falling. We underwent drainage of the swelling area, found pus 100cc and took a sample for pathological examination. The result was embryonal rhabdomyosarcoma. Prostate volume was 122cc, PSA 5,32 and PSAD 0,04. The CT scan result was solid mass size 15x8x18 cm at perineum enhance to the pelvic cavity, push the bladder to the superior, rectum to posterior, and urethra posterior to the left side. We diagnosed this patient as Embryonal Rhabdomyosarcoma prostate T2bG1N0M0 (stage 3) group 3 and intermediate-risk group. The patient underwent VAC chemotherapy based on D.9803 (IRS V) protocol and planned radiotherapy, but it stopped at halfway because of profuse bleeding. Embryonal Rhabdomyosarcoma is an aggressive tumor, especially in adults. However, there was limited evidence and guideline to diagnose and manage the disease.

Skeletal Muscle Subpopulation Rearrangements upon Rhabdomyosarcoma Development through Single-Cell Mass Cytometry

The embryonal rhabdomyosarcoma (eRMS) is a soft tissue sarcoma commonly affecting the head and neck, the extremities and the genitourinary tract. To contribute to revealing the cell types that may originate this tumor, we exploited mass cytometry, a single-cell technique that, by using heavy-metal-tagged antibodies, allows the accurate monitoring of the changes occurring in the mononuclear cell composition of skeletal muscle tissue during tumor development. To this end, we compared cell populations of healthy muscles with those from spatiotemporal-induced eRMS tumors in a mouse model (LSL-Kras^G12D/+;Tp53^Fl/Fl) that can be used to develop rhabdomyosarcoma by means of infection with an adenovirus vector expressing Cre (Ad-Cre) recombinase. By monitoring different time points after tumor induction, we were able to analyze tumor progression and composition, identifying fibro/adipogenic progenitors (FAPs) as the cell type that, in this model system, had a pivotal role in tumor development. In vitro studies highlighted that both FAPs and satellite cells (SCs), upon infection with the Ad-Cre, acquired the potential to develop rhabdomyosarcomas when transplanted into immunocompromised mice. However, only infected FAPs had an antigen profile that was similar to embryonal rhabdomyosarcoma cells. Overall, our analysis supports the involvement of FAPs in eRMS development.

Pathogenic Germline Variants in Cancer Susceptibility Genes in Children and Young Adults With Rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is the most common pediatric soft-tissue sarcoma and accounts for 3% of all pediatric cancer. In this study, we investigated germline sequence and structural variation in a broad set of genes in two large, independent RMS cohorts.

MATERIALS AND METHODS

Genome sequencing of the discovery cohort (n = 273) and exome sequencing of the secondary cohort (n = 121) were conducted on germline DNA. Analyses were performed on 130 cancer susceptibility genes (CSG). Pathogenic or likely pathogenic (P/LP) variants were predicted using the American College of Medical Genetics and Genomics (ACMG) criteria. Structural variation and survival analyses were performed on the discovery cohort.

RESULTS

We found that 6.6%-7.7% of patients with RMS harbored P/LP variants in dominant-acting CSG. An additional approximately 1% have structural variants (ATM, CDKN1C) in CSGs. CSG variants did not influence survival, although there was a significant correlation with an earlier age of tumor onset. There was a nonsignificant excess of P/LP variants in dominant inheritance genes in the patients with FOXO1 fusion-negative RMS patients versus the patients with FOXO1 fusion-positive RMS. We identified pathogenic germline variants in CSGs previously (TP53, NF1, DICER1, mismatch repair genes), rarely (BRCA2, CBL, CHEK2, SMARCA4), or never (FGFR4) reported in RMS. Numerous genes (TP53, BRCA2, mismatch repair) were on the ACMG Secondary Findings 2.0 list.

CONCLUSION

In two cohorts of patients with RMS, we identified pathogenic germline variants for which gene-specific therapies and surveillance guidelines may be beneficial. In families with a proband with an RMS-risk P/LP variant, genetic counseling and cascade testing should be considered, especially for ACMG Secondary Findings genes and/or with gene-specific surveillance guidelines.

Establishment and Characterization of a Sclerosing Spindle Cell Rhabdomyosarcoma Cell Line with a Complex Genomic Profile

Sclerosing spindle cell rhabdomyosarcoma (SSRMS) is a rare rhabdomyosarcomas (RMS) subtype. Especially cases bearing a myogenic differentiation 1 (MYOD1) mutation are characterized by a high recurrence and metastasis rate, often leading to a fatal outcome. SSRMS cell lines are valuable in vitro models for studying disease mechanisms and for the preclinical evaluation of new therapeutic approaches. In this study, a cell line established from a primary SSRMS tumor of a 24-year-old female after multimodal chemotherapeutic pretreatment has been characterized in detail, including immunohistochemistry, growth characteristics, cytogenetic analysis, mutation analysis, evaluation of stem cell marker expression, differentiation potential, and tumorigenicity in mice. The cell line which was designated SRH exhibited a complex genomic profile, including several translocations and deletions. Array-comparative genomic hybridization (CGH) revealed an overall predominating loss of gene loci. The mesenchymal tumor origin was underlined by the expression of mesenchymal markers and potential to undergo adipogenic and osteogenic differentiation. Despite myogenic marker expression, terminal myogenic differentiation was inhibited, which might be elicited by the MYOD1 hotspot mutation. In vivo tumorigenicity could be confirmed after subcutaneous injection into NOD/SCID/γ_c^null mice. Summarized, the SRH cell line is the first adult SSRMS cell line available for preclinical research on this rare RMS subtype.

Curcumin loaded zinc oxide nanoparticles for activity-enhanced antibacterial and anticancer applications

Zinc oxide nanoparticles and curcumin have been shown to be excellent antimicrobial agents and promising anticancer agents, both on their own as well as in combination. Together, they have potential as alternatives/supplements to antibiotics and traditional anticancer drugs. In this study, different morphologies of zinc oxide-grafted curcumin nanocomposites (ZNP-Cs) were synthesized and characterized using SEM, TGA, FTIR, XRD and UV-vis spectrophotometry. Antimicrobial assays were conducted against both Gram negative and Gram-positive bacterial stains. Spherical ZnO-curcumin nanoparticles (SZNP-Cs) and rod-shaped ZnO-curcumin nanoparticles showed the most promising activity against tested bacterial strains. The inhibition zones for these curcumin-loaded ZnO nanocomposites were consistently larger than their bare counterparts or pure curcumin, revealing an additve effect between the ZnO and curcumin components. The potential anticancer activity of the synthesized nanocomposites was studied on the rhabdomyosarcoma RD cell line via MTT assay, while their cytotoxic effects were tested against human embryonic kidney cells using the resazurin assay. SZNP-Cs exhibited the best balance between the two, showing the lowest toxicity against healthy cells and good anticancer activity. The results of this investigation demonstrate that the nanomatrix synthesized can act as an effective, additively-enhanced combination delivery/therapeutic agent, holding promise for anticancer therapy and other biomedical applications.

Sequential combinations of chemotherapeutic agents with BH3 mimetics to treat rhabdomyosarcoma and avoid resistance

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in childhood and adolescence. Refractory/relapsed RMS patients present a bad prognosis that combined with the lack of specific biomarkers impairs the development of new therapies. Here, we utilize dynamic BH3 profiling (DBP), a functional predictive biomarker that measures net changes in mitochondrial apoptotic signaling, to identify anti-apoptotic adaptations upon treatment. We employ this information to guide the use of BH3 mimetics to specifically inhibit BCL-2 pro-survival proteins, defeat resistance and avoid relapse. Indeed, we found that BH3 mimetics that selectively target anti-apoptotic BCL-xL and MCL-1, synergistically enhance the effect of clinically used chemotherapeutic agents vincristine and doxorubicin in RMS cells. We validated this strategy in vivo using a RMS patient-derived xenograft model and observed a reduction in tumor growth with a tendency to stabilization with the sequential combination of vincristine and the MCL-1 inhibitor S63845. We identified the molecular mechanism by which RMS cells acquire resistance to vincristine: an enhanced binding of BID and BAK to MCL-1 after drug exposure, which is suppressed by subsequently adding S63845. Our findings validate the use of DBP as a functional assay to predict treatment effectiveness in RMS and provide a rationale for combining BH3 mimetics with chemotherapeutic agents to avoid tumor resistance, improve treatment efficiency, and decrease undesired secondary effects.

Machine Learning Approach to Forecast Chemotherapy-Induced Haematological Toxicities in Patients with Rhabdomyosarcoma

Developing precision medicine is a major trend in clinical oncology. The main adverse effects of ifosfamide, actinomycin D and vincristine (IVA) treatment for rhabdomyosarcoma are haematological toxicities such as neutropenia or thrombocytopenia. The severity of these effects vary among patients but their dynamic profiles are similar. A non-empirical adjustment of the chemotherapy dose to avoid severe toxicities could help secure the treatment administration. Twenty-four patients with rhabdomyosarcoma treated with IVA chemotherapy courses were selected. Before and during each cycle, routine multiple blood cell counts were performed allowing for a dynamic study of the haematological toxicities. We developed a machine learning analysis using a gradient boosting regression technique to forecast the ifosfamide induced haematological toxicities as a function of neutrophils and platelets initial levels and the initial ifosfamide dose. To validate models’ accuracy, predicted and observed neutrophils and platelets levels were compared. The model was able to reproduce the dynamic profiles of the haematological toxicities. Among all cycles, the mean absolute errors between predicted and observed neutrophils and platelets levels were 1.0 and 72.8 G/L, respectively. Adjusting a patient’s ifosfamide dose based upon the predicted haematological toxicity levels at the end of a treatment cycle could enable tailored treatment.

The expanded endonasal approach in pediatric skull base surgery: A review

OBJECTIVE

Surgery of the pediatric skull base has multiple unique challenges and has seen recent rapid advances. The objective of this review is to assess key issues in pediatric skull base surgery (SBS), including anatomic limitations, surgical approaches, reconstruction techniques, postoperative care, complications, and outcomes.

DATA SOURCES

PubMed literature review.

REVIEW METHODS

A review of the literature was conducted to assess the challenges, recent advances, and reported outcomes in pediatric SBS.

RESULTS

The pediatric skull base presents multiple anatomic challenges, including variable patterns of pneumatization, narrow piriform aperture width, and narrow intercarotid distance at the level of the cavernous sinus but not the superior clivus. These issues may be particularly challenging in patients less than 2 years of age. Endoscopic endonasal approaches in the sagittal and coronal plane have been applied to the pediatric skull base while open approaches may still be necessary in the setting of extensive intracranial or orbital disease, as well as disease lateral to critical neurovascular structures. While the nasoseptal flap was initially called into question for pediatric cases, it has been shown through multiple reports to be a feasible and robust reconstructive option. Complications and outcomes often depend upon the pathology. In children, response to noxious stimuli, ability to avoid Valsalva, and adherence to nasal precautions is variable. The use of lumbar drains is more common in pediatric than adult patients.

CONCLUSION

While the pediatric skull base presents unique challenges, outcomes data support that endoscopic endonasal approaches are a pertinent surgical technique in appropriately selected patients.

LEVEL OF EVIDENCE

3a.

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.

Wilms’ tumor 1 protein expression in embryonal and alveolar rhabdomyosarcoma and its association with clinical prognostic factors: a cross-sectional study

BACKGROUND Embryonal rhabdomyosarcoma (ERMS) and alveolar rhabdomyosarcoma (ARMS) are the two major histological types commonly found in the pediatric population, which have different morphology and genetic profile. Wilms’ tumor 1 (WT1) is an antigen highly expressed in solid tumors, including rhabdomyosarcoma, and a potential immunotherapy target. Only a few studies have attempted to determine WT1 expression in rhabdomyosarcoma. This study was conducted to demonstrate WT1 expression in ERMS, ARMS and associate it with established prognostic factors. METHODS A cross-sectional study was conducted at the Department of Anatomical Pathology, Faculty of Medicine, Universitas Indonesia, Cipto Mangunkusumo Hospital, Jakarta using archival data from January 2011 to December 2017. 30 from 102 ERMS cases and 16 from 28 ARMS cases were included in this study. Data of age, tumor size, and location were collected. All cases were stained by WT1 immunohistochemistry. The expression was assessed semiquantitatively using histoscore (H-score) formula. An independent t-test was used to compare WT1 expression between ERMS and ARMS. Correlation analysis was used to evaluate the relationship between WT1 expression and prognostic factors. RESULTS All ERMS and ARMS cases expressed WT1 in diffuse, moderate to strong staining. ERMS show higher WT1 expression than ARMS (H-score 179.9 versus 149.5) (p = 0.014). Strong WT1 expression mostly found in patient age <20 years and non favourable location. Moderate WT1 expression mostly found in cases with tumor size >5 cm. CONCLUSIONS WT1 expression was higher in ERMS cases than in ARMS cases, which the expressions were similar in different age, tumor size, and location groups.

[Intraspinal metastasis of alveolar rhabdomyosarcoma: A case report]

This paper reported a case of cervical intraspinal metastasis of alveolar rhabdomyosarcoma (ARMS). The clinicopathological features, surgical treatment, chemotherapy and prognosis were introduced and the current literature was reviewed. The diagnosis, differential diagnosis, treatment, molecular features and prognosis of the disease were comprehensively analyzed to improve clinicians' knowledge of this rare disease. The primary lesion appeared about 1 year ago which was painless mass of left hand whose size was about 2 cm×2 cm. After conservative treatment, the mass gradually enlarged and the mass was resected. Postoperative pathology revealed embryonic rhabdomyosarcoma. Postoperative chemotherapy with recombinant human endostatin, liposomal doxorubicin and ifosfamide was performed. The left neck mass was found about 3 months ago, and then the left neck mass was resected under general anesthesia. Postoperative pathological examination showed small round cell malignant tumors. Severe left upper extremity pain began about 2 weeks ago with nocturnal pain and supine pain. Non-steroidal anti-inflammatory drugs were needed to relieve pain which was accompanied by numbness and weakness of the left upper extremity. MRI showed a intraspinal tumor at C5. The left thumb and index finger were absent. Hypoesthesia, muscle atrophy and hypotonia of the left upper limb were confirmed. The muscle strength of biceps brachii and deltoid muscle of the left upper limb was grade 0, the muscle strength of extensor carpus and interphalangeal muscle was grade II, the muscle strength of intrinsic muscles of hands was grade I. The tendon reflex of the left upper limb disappeared. Intraspinal mass was removed and the pain was relieved. But there was no significant change in the muscle strength of the left upper limb. Pathological examination revealed small cell malignancies which were poorly differentiated with diffuse patchy distribution and disordered arrangement. The tumor cells had round, oval or irregular nuclei, and few cytoplasms were positive for Myogenin and MyoD1. FISH test of FOXO1 gene was positive. More than 50% of nuclei showed redgreen signal separation, and the distance between redgreen signals was larger than double diameter of the signal points, which supported ARMS. Total resection of intraspinal tumors was achieved and postoperative chemotherapy was admitted. But intraspinal disseminated metastasis occurred rapidly. ARMS was rare, aggressive tumor with poor prognosis. Subdural metastasis was rare. Correct diagnosis and classification can be made only with help of modern molecular diagnostic methods, which is effective to guide the treatment.

Paediatric proton therapy

Proton beam therapy is a highly conformal form of radiation therapy, which currently represents an important therapeutic component in multidisciplinary management in paediatric oncology. The precise adjustability of protons results in a reduction of radiation-related long-term side-effects and secondary malignancy induction, which is of particular importance for the quality of life. Proton irradiation has been shown to offer significant advantages over conventional photon-based radiotherapy, although the biological effectiveness of both irradiation modalities is comparable. This review evaluates current data from clinical and dosimetric studies on the treatment of tumours of the central nervous system, soft tissue and bone sarcomas of the head and neck region, paraspinal or pelvic region, and retinoblastoma. To date, the clinical results of irradiating childhood tumours with high-precision proton therapy are promising both with regard to tumour cure and the reduction of adverse events. Modern proton therapy techniques such as pencil beam scanning and intensity modulation are increasingly established modern facilities. However, further investigations with larger patient cohorts and longer follow-up periods are required, in order to be able to have clear evidence on clinical benefits.

Isolated Breast Relapse after Metastatic Alveolar Rhabdomyosarcoma in a Young Premenarcheal Girl: What Could Have Been Done?

Alveolar rhabdomyosarcoma (RMS) is one of the most common pediatric soft-tissue neoplasms. Breast involvement either as primary tumor or metastasis is extremely rare. Herein, we report a case of primary limb alveolar RMS with breast metastases in a young premenarcheal girl that relapsed only to the metastatic breast site after achieving complete response. Accordingly, we believe that investigations of the mammary glands should be part of the routine diagnostic workup in adolescent females with RMS. Local therapeutic measures to control breast disease, including surgery or radiotherapy has to be considered for better prognosis. Newer radiation modalities aiming at reducing side effects should be developed.

Pediatric Tracheal Rhabdomyosarcoma Masquerading as a Granuloma

We describe a posterior wall intratracheal embryonal rhabdomyosarcoma (RMS) arising in a 6-year-old tracheostomized child masquerading as reactive granulation tissue and review all reported cases of pediatric intratracheal RMS. The child underwent laser debulking of the tumor and postoperative radiation and chemotherapy with no evidence of recurrence at 2-year follow-up. A literature review revealed four previous cases of pediatric primary tracheal or intratracheal RMS, and remission was achieved in all but one case with surgery, chemotherapy, and radiation. Pathologic evaluation of tracheal mucosal granulation tissue may merit consideration, particularly in patients with increased risk factors.

TP53 in bone and soft tissue sarcomas

Genomic and functional study of existing and emerging sarcoma targets, such as fusion proteins, chromosomal aberrations, reduced tumor suppressor activity, and oncogenic drivers, is broadening our understanding of sarcomagenesis. Among these mechanisms, the tumor suppressor p53 (TP53) plays significant roles in the suppression of bone and soft tissue sarcoma progression. Although mutations in TP53 were thought to be relatively low in sarcomas, modern techniques including whole-genome sequencing have recently illuminated unappreciated alterations in TP53 in osteosarcoma. In addition, oncogenic gain-of-function activities of missense mutant p53 (mutp53) have been reported in sarcomas. Moreover, new targeting strategies for TP53 have been discovered: restoration of wild-type p53 (wtp53) activity through inhibition of TP53 negative regulators, reactivation of the wtp53 activity from mutp53, depletion of mutp53, and targeting of vulnerabilities in cells with TP53 deletions or mutations. These discoveries enable development of novel therapeutic strategies for therapy-resistant sarcomas. We have outlined nine bone and soft tissue sarcomas for which TP53 plays a crucial tumor suppressive role. These include osteosarcoma, Ewing sarcoma, chondrosarcoma, rhabdomyosarcoma (RMS), leiomyosarcoma (LMS), synovial sarcoma, liposarcoma (LPS), angiosarcoma, and undifferentiated pleomorphic sarcoma (UPS).

Physicochemical and pathohistological changes in experimental fibrosarcoma tumors of hamsters treated with metformin and itraconazole

The anticancer effects of metformin (an antihyperglycaemic agent) and itraconazole (an antifungal agent), which are established non-oncologic drugs, were investigated in the present study. The weight, diameter, volume, density, surface, surface to volume ratio and immunohistochemistry of experimental fibrosarcoma tumors were investigated in hamsters treated with metformin and itraconazole. Briefly, the hamsters were injected with BHK-21/C13 cells in order to induce fibrosarcoma, and the animals were treated daily with metformin, itraconazole or a combination of the two drugs. Subsequently, blood samples were obtained for biochemical analyses and the tumors were excised, weighed and measured. The tumor samples were pathohistologically and immunohistochemically assessed for proliferation marker protein Ki-67, hematopoietic progenitor cell antigen CD34, cytochrome c oxidase subunit 4 (COX4), glucose transporter 1 (GLUT1) and inducible nitric oxide synthase (iNOS), and vital organs were toxicologically tested. Ki-67-positivity and cytoplasmic marker (CD34, COX4, GLUT1, iNOS) immunoexpression in the tumor samples were quantified. The results revealed that the combination of metformin and itraconazole significantly altered the physicochemical and pathohistological characteristics of the hamster fibrosarcoma tumors, including absolute and relative weight, volume, density, length, surface area, surface to volume ratio, Ki-67-positivity and the immunoexpression of cytoplasmic markers, without indications of toxicity. Furthermore, metformin with itraconazole demonstrated antiproliferative functions in cervical carcinoma HeLa, colon carcinoma HT-29, lung carcinoma A549 and fibrosarcoma BHK-21/C13 cells, with markedly lower cytotoxicity in the normal fetal lung MRC-5 cells. In conclusion, the administration of metformin in combination with itraconazole may inhibit the growth of fibrosarcoma tumors in vivo and the proliferation of various malignant cell lines in vitro, suggesting that this may be an effective and safe approach as a nontoxic anticancer adjuvant and relapse prevention therapy.

Adult Alveolar Rhabdomyosarcoma on Extremity, Successful Treatment with Radiotherapy following Chemotherapy: Serial Case Report

Alveolar rhabdomyosarcoma (RMS) is one of the four subtypes of RMS. Alveolar RMS is the rare type found in adults, with the worse prognosis. We report 2 serial cases of alveolar RMS on extremity which was only treated with subtotal excision or incision biopsy. We further gave a total dose of 70 Gy radiotherapy on the local tumor and 50 Gy prophylaxis dose on regional lymph node after 6 cycles of anthracyclines-based chemotherapy. Postradiotherapy, contrast computed tomography scan revealed no tumor mass left (complete response).

The palladacycle complex AJ-5 induces apoptotic cell death while reducing autophagic flux in rhabdomyosarcoma cells

Rhabdomyosarcoma (RMS) forms in skeletal muscle and is the most common soft tissue sarcoma in children and adolescents. Current treatment is associated with debilitating side effects and treatment outcomes for patients with metastatic disease are dismal. Recently, a novel binuclear palladacycle, AJ-5, was shown to exert potent cytotoxicity in melanoma and breast cancer and to present with negligible adverse effects in mice. This study investigates the anti-cancer activity of AJ-5 in alveolar and embryonal RMS. IC50 values of ≤ 0.2 µM were determined for AJ-5 and it displayed a favourable selectivity index of >2. Clonogenic and migration assays showed that AJ-5 inhibited the ability of RMS cells to survive and migrate, respectively. Western blotting revealed that AJ-5 induced levels of key DNA damage response proteins (γH2AX, p-ATM and p-Chk2) and the p38/MAPK stress pathway. This correlated with an upregulation of p21 and a G1 cell cycle arrest. Annexin V-FITC/propidium iodide staining revealed that AJ-5 induced apoptosis and necrosis. Apoptosis was confirmed by the detection of cleaved PARP and increased levels and activity of cleaved caspases-3, -7, -8 and -9. Furthermore, AJ-5 reduced autophagic flux as shown by reduced LC3II accumulation in the presence of bafilomycin A1 and a significant reduction in autophagosome flux J. Finally, pharmacokinetic studies in mice show that AJ-5 has a promising half-life and that its volume of distribution is high, its clearance low and its intraperitoneal absorption is good. Together these findings suggest that AJ-5 may be an effective chemotherapeutic with a desirable mechanism of action for treating drug-resistant and advanced sarcomas.

Circ-ZNF609 regulates G1-S progression in rhabdomyosarcoma

Circular RNAs (circRNAs) represent a class of covalently closed RNAs, derived from non-canonical splicing events, which are expressed in all eukaryotes and often conserved among different species. We previously showed that the circRNA originating from the ZNF609 locus (circ-ZNF609) acts as a crucial regulator of human primary myoblast growth: indeed, the downregulation of the circRNA, and not of its linear counterpart, strongly reduced the proliferation rate of in vitro cultured myoblasts. To deepen our knowledge about circ-ZNF609 role in cell cycle regulation, we studied its expression and function in rhabdomyosarcoma (RMS), a pediatric skeletal muscle malignancy. We found that circ-ZNF609 is upregulated in biopsies from the two major RMS subtypes, embryonal (ERMS) and alveolar (ARMS). Moreover, we discovered that in an ERMS-derived cell line circ-ZNF609 knock-down induced a specific block at the G1-S transition, a strong decrease of p-Akt protein level and an alteration of the pRb/Rb ratio. Regarding p-Akt, we were able to show that circ-ZNF609 acts by counteracting p-Akt proteasome-dependent degradation, thus working as a new regulator of cell proliferation-related pathways. As opposed to ERMS-derived cells, the circRNA depletion had no cell cycle effects in ARMS-derived cells. Since in these cells the p53 gene resulted downregulated, with a concomitant upregulation of its cell cycle-related target genes, we suggest that this could account for the lack of circ-ZNF609 effect in ARMS.

Rhabdomyosarcoma and Extraosseous Ewing Sarcoma

Rhabdomyosarcoma (RMS) is a malignant tumor that represents the most common form of pediatric soft tissue sarcoma. It arises from mesenchymal origin and forms part of the group of small round blue cell tumors of childhood. It has a constant annual incidence of 4.5 cases per 1,000,000 children. The known histological diagnosis of the two major subtypes (embryonal and alveolar) has been recently enhanced by tumor biological markers and molecular differentiation diagnostic tools that have improved not only the updated classification based on risk stratification, but also the treatment approach based on the clinical group. Ewing sarcoma (ES) is a round cell tumor, highly malignant and poorly differentiated that is currently the second most common malignant bone tumor in children. In rare instances, it develops from an extraskeletal origin, classified as extraosseous Ewing sarcoma (EES). We provide an updated, evidence-based and comprehensive review of the molecular diagnosis, clinical and diagnostic approach and a multidisciplinary medical and surgical management according to the latest standard of care for the treatment of pediatric RMS and EES.

Pleomorphic rhabdomyosarcoma metastasis to small intestine causing intussusception: A case report

RATIONALE

Pleomorphic rhabdomyosarcoma (PRMS) is a rare soft tissue malignancy which is frequently misdiagnosed and associated with metastasis to the lungs, lymph nodes, and bone marrow. Case studies are needed to improve the awareness of the disease and our understanding of it.

PATIENT CONCERNS

In this study, we present a case of a 36-year-old man with a lesion on the right back shoulder. Lesion was confirmed by magnetic resonance imaging (MRI) around the right armpit, subscapularis, deltoid, and infraspinatus muscle, with oozing surrounding soft tissues.

DIAGNOSIS

The tumor was diagnosed as PRMS which metastasized to the intestine, where it caused intussusception.

INTERVENTIONS

The patient was treated by complete surgery in combination with neo-adjuvant chemotherapy including ifosfamide and epirubicin.

OUTCOME

The patient remained alive 6 months after the treatment with no recurrence and metastasis.

LESSON

PRMS can be aggressive, and surgical treatment in combination with multidrug chemotherapy can be used in the management.

Pannexin 1 inhibits rhabdomyosarcoma progression through a mechanism independent of its canonical channel function

Rhabdomyosarcoma (RMS) is an aggressive soft tissue sarcoma of childhood thought to arise from impaired differentiation of skeletal muscle progenitors. We have recently identified Pannexin 1 (PANX1) channels as a novel regulator of skeletal myogenesis. In the present study, we determined that PANX1 transcript and protein levels are down-regulated in embryonal (eRMS) and alveolar RMS (aRMS) patient-derived cell lines and primary tumor specimens as compared to differentiated skeletal muscle myoblasts and tissue, respectively. While not sufficient to overcome the inability of RMS to reach terminal differentiation, ectopic expression of PANX1 in eRMS (Rh18) and aRMS (Rh30) cells significantly decreased their proliferative and migratory potential. Furthermore, ectopic PANX1 abolished 3D spheroid formation in eRMS and aRMS cells and induced regression of established spheroids through induction of apoptosis. Notably, PANX1 expression also significantly reduced the growth of human eRMS and aRMS tumor xenografts in vivo. Interestingly, PANX1 does not form active channels when expressed in eRMS (Rh18) and aRMS (Rh30) cells and the addition of PANX1 channel inhibitors did not alter or reverse the PANX1-mediated reduction of cell proliferation and migration. Moreover, expression of channel-defective PANX1 mutants not only disrupted eRMS and aRMS 3D spheroids, but also inhibited in vivo RMS tumor growth. Altogether our findings suggest that PANX1 alleviates RMS malignant properties in vitro and in vivo through a process that is independent of its canonical channel function.

Therapeutic Approaches Targeting PAX3-FOXO1 and Its Regulatory and Transcriptional Pathways in Rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is a family of soft tissue cancers that are related to the skeletal muscle lineage and predominantly occur in children and young adults. A specific chromosomal translocation t(2;13)(q35;q14) that gives rise to the chimeric oncogenic transcription factor PAX3-FOXO1 has been identified as a hallmark of the aggressive alveolar subtype of RMS. PAX3-FOXO1 cooperates with additional molecular changes to promote oncogenic transformation and tumorigenesis in various human and murine models. Its expression is generally restricted to RMS tumor cells, thus providing a very specific target for therapeutic approaches for these RMS tumors. In this article, we review the recent understanding of PAX3-FOXO1 as a transcription factor in the pathogenesis of this cancer and discuss recent developments to target this oncoprotein for treatment of RMS.

Targeting Anaplastic Lymphoma Kinase (ALK) in Rhabdomyosarcoma (RMS) with the Second-Generation ALK Inhibitor Ceritinib

Background

The receptor tyrosine kinase (RTK) anaplastic lymphoma kinase (ALK) has been implicated in the tumorigenesis of rhabdomyosarcoma (RMS). However, the exact role of ALK in RMS is debatable and remains to be elucidated.

Objective

To determine the in vitro and in vivo effects and mechanism of action of the second-generation ALK inhibitor ceritinib on RMS cell growth.

Methods

Effects of ceritinib on cell proliferation, wound healing, cell cycle, and RTK signaling were determined in alveolar and embryonal rhabdomyosarcoma (ARMS, ERMS). In addition, possible synergistic effects of combined treatment with ceritinib and the Abl/Src family kinase inhibitor dasatinib were determined.

Results

Ceritinib treatment led to decreased cell proliferation, cell cycle arrest, apoptosis, and decreased in vivo tumor growth for the ARMS subtype. ERMS cell lines were less affected and showed no cell cycle arrest or apoptosis. Both subtypes lacked intrinsic ALK phosphorylation, and ceritinib was shown to affect the IGF1R signaling pathway. High levels of phosphorylated Src (Tyr416) were present following ceritinib treatment, making combined treatment with a Src inhibitor a potential treatment option. Combined treatment of ceritinib and dasatinib showed synergistic effects in both ERMS and ARMS cell lines.

Conclusion

This study shows that monotherapy with an ALK inhibitor, such as ceritinib, in RMS, has no effect on ALK signaling. However, the synergistic effects of ceritinib and dasatinib are promising, most probably due to targeting of IGF1R and Src.

Electronic supplementary material

The online version of this article (10.1007/s11523-017-0528-z) contains supplementary material, which is available to authorized users.

EGR1 interacts with TBX2 and functions as a tumor suppressor in rhabdomyosarcoma

EGR1, one of the immediate-early response genes, can function as a tumor suppressor gene or as an oncogene in cancer. The function of EGR1 has not been fully characterized in rhabdomyosarcoma (RMS), a pediatric cancer derived from the muscle linage. We found that EGR1 is downregulated in the alveolar RMS (ARMS) subtype but expressed at levels comparable to normal skeletal muscle in embryonal RMS (ERMS). We found that overexpression of EGR1 in ARMS significantly decreased cell proliferation, mobility, and anchorage-independent growth while also promoting differentiation. We found that EGR1 interacts with TBX2, which we have shown functions as an oncogene in RMS. The interaction inhibits EGR1 dependent gene expression, which includes the cell cycle regulators p21 and PTEN as well as other important cell growth drivers such as NDRG1 and CST6. We also found that EGR1 induced apoptosis by triggering the intrinsic apoptosis pathway. EGR1 also activated two pro-apoptotic factors, BAX and dephosphorylated BAD, which are both located upstream of the caspase cascades in the intrinsic pathway. EGR1 also sensitized RMS cells to chemotherapeutic agents, suggesting that activating EGR1 may improve therapeutic targeting by inducing apoptosis. Our results establish the important role of EGR1 in understanding RMS pathology.

A novel retinoid X receptor agonist, UAB30, inhibits rhabdomyosarcoma cells in vitro

BACKGROUND

While patients with early-stage rhabdomyosarcoma (RMS) have seen steady improvement in prognosis over the last 50 y, those with advanced-stage or high-grade disease continue to have a dismal prognosis. Retinoids have been shown to cause growth suppression and terminal differentiation in RMS cells, but the toxicities associated with retinoic acid limit its use. Rexinoids provide an alternative treatment approach to retinoic acid. Rexinoids primarily bind the retinoid X receptor with minimal retinoic acid receptor binding, the entity responsible for many of the toxicities of retinoid therapies. UAB30 is a novel rexinoid with limited toxicities. We hypothesized that UAB30 would lead to decreased cell survival in RMS.

MATERIALS AND METHODS

Two RMS cell lines, one embryonal (RD) subtype and one alveolar (St. Jude Cancer Research Hospital 30) subtype, were used. Cells were treated with UAB30, and cytotoxicity, proliferation, mobility, and apoptosis were evaluated.

RESULTS

UAB30 significantly decreased RMS tumor cell viability and proliferation. Invasion, migration, and attachment-independent growth were reduced following UAB30 treatment. UAB30 also resulted in apoptosis and G1 cell cycle arrest. UAB30 affected both the alveolar and embryonal RMS cell lines in a similar fashion.

CONCLUSIONS

The results of these studies suggest a potential therapeutic role for the low-toxicity synthetic retinoid X receptor selective agonist, UAB30, in RMS treatment.

Prohibitin 2 localizes in nucleolus to regulate ribosomal RNA transcription and facilitate cell proliferation in RD cells

Prohibitin 2 (PHB2), as a conserved multifunctional protein, is traditionally localized in the mitochondrial inner membrane and essential for maintenance of mitochondrial function. Here, we investigated the role of PHB2 in human rhabdomyosarcoma (RMS) RD cells and found substantial localization of PHB2 in the nucleolus. We demonstrated that PHB2 knockdown inhibited RD cell proliferation through inducing cell cycle arrest and suppressing DNA synthesis. Meanwhile, down-regulation of PHB2 also induced apoptosis and promoted differentiation in fractions of RD cells. In addition, PHB2 silencing led to altered nucleolar morphology, as observed by transmission electron microscopy, and impaired nucleolar function, as evidenced by down-regulation of 45S and 18S ribosomal RNA synthesis. Consistently, upon PHB2 knockdown, occupancy of c-Myc at the ribosomal DNA (rDNA) promoter was attenuated, while more myoblast determination protein 1 (MyoD) molecules bound to the rDNA promoter. In conclusion, our findings suggest that nucleolar PHB2 is involved in maintaining nucleolar morphology and function in RD cells by regulating a variety of transcription factors, which is likely to be one of the underlying mechanisms by which PHB2 promotes tumor proliferation and represses differentiation. Our study provides new insight into the pathogenesis of RMS and novel characterizations of the highly conserved PHB2 protein.