Robotic retroperitoneal lymph node dissection for paratesticular rhabdomyosarcoma in adolescents: a case series.

Robotic assisted (RA) retroperitoneal lymph node dissection (RPLND) has grown in popularity as it offers decreased morbidity and faster recovery compared to the open technique. Proponents of open surgery raised concerns about the oncological fidelity of the RA approach for testicular tumors where complete resection is needed. In boys > 10 years with paratesticular rhabdomyosarcoma (RMS), RPLND is indicated for staging purposes only. In this population, the RA technique should provide its benefits without concerns for oncological compromise. We present an analysis of RA-RPLND for boys with paratesticular RMS. We queried our institution's prospectively collected database of pediatric robotic cases for patients undergoing RA-RPLND post-radical orchiectomy for paratesticular mass, confirmed by pathology as RMS. Demographic, surgical, follow-up, and oncological outcomes were evaluated between 2017 and 2023. Five patients underwent RA-RPLND for paratesticular RMS. The median age was 16.1 years (15-17), with median OR time of 456 min (357-508). No conversions to open occurred. Inpatient median total opioid use was 1.8 (0.4-2.7) morphine equivalent/kg. The median lymph node yield was 27 (8-44) and post-op length of stay was 3 days (2-5). The median time to initiating adjuvant chemotherapy was 10.5 days (7-13). One patient had complications: pneumothorax attributed to central line placement and chyle leak that resolved in 1 week with dietary restriction. Our series demonstrates the feasibility, safety, and efficacy of the RA approach for RPLND in pediatric patients with paratesticular RMS. This is the most extensive case series currently in the literature and the only one exclusively done for paratesticular RMS.

A report on second neo-plasms in seven children with solid tumors.

OBJECTIVE: This study aims to investigate the characteristics and related high risk factors of second neoplasms after chemotherapy and radiotherapy in children with solid tumors. METHODS: The detailed clinical data of seven children with malignant solid tumors, who were treated in our department, were retrospectively analyzed, in order to summarize the clinical characteristics of the secondary onset of second neoplasms, and determined the risk factors related to the occurrence of second neoplasms. RESULTS: (1) Clinical characteristics: Among the seven children with malignant solid tumors, three children had rhabdomyosarcoma (3/132, 2.27%), two children had hepatoblastoma (2/313, 0.64%), one child had neuroblastoma (1/305, 0.33%), and one child had inflammatory myofibroblastoma (1/3, 33.33%). Furthermore, among these children, four children were boys and three children were girls, and their onset age ranged within 5-34 months, with a median onset age of 27 months. Moreover, among these children, three children were ≤1 year old. All second neoplasms exhibited symptoms, and the diagnosis was made after the complete remission of the first primary tumor. The time interval between these two tumors was within 17-78 months, and the median time was 38 months. Three of seven children with rhabdomyosarcoma were treated with chemotherapy in combination with radiotherapy, while four children only received the chemotherapy. The chemotherapy cycles were 6-39 times, and the median chemotherapy cycles were 10 times. Among these children, one child with relapsed stage IV rhabdomyosarcoma and one child with stage IV retroperitoneal neuroblastoma had 39 cycles and 33 cycles of chemotherapy respectively. (2) Characteristics of the accumulated doses of high-risk chemotherapy drugs: The accumulated dose of cyclophosphamide in six patients was within 2.47-44.45 g/m2, with a median of 6.14 g/m2. The accumulated dose of ifosfamide in five patients was within 13.63-96.41 mg/m2, with a median of 31.23g/m2. The accumulated dose of etoposide in six patients was within 1,237.35-3,754.95 mg/m2, with a median of 1,548.67 mg/m2. The accumulated dose of anthracyclines in seven patients was within 150.68-843.78 mg/m2, with a median of 329.73 mg/m2. The accumulated dose of vincristine in seven patients was within 3.11-18.89 mg/m2, with a median of 15.92 mg/m2. The accumulated dose of cisplatin in seven patients was within 271.23-1,681.59 mg/m2, with a median of 733.07 mg/m2. Children with abdominal inflammatory myofibroblastic tumors did not apply cyclophosphamide, ifosfamide and etoposide regimens. The main chemotherapy drugs consisted of methotrexate, pirarubicin, cisplatin and vincristine. (3) Radiotherapy doses. (4) Characteristics of second neoplasms: Among the seven children with second neoplasms, five children had leukemia, 3 patients with rhabdomyosarcoma were combined with radiotherapy. The doses of radiation were 40 and 45GY" after "(3) Radiotherapy doses (four children had acute myeloid leukemia and one children had acute B-lymphoblastic leukemia), one child had myelodysplastic syndrome, and one child had myeloid sarcoma. Furthermore, among these seven children, four children (4/7) had abnormal chromosomes, two children were normal, and one child gave up the treatment and underwent the chromosome test after the diagnosis of second neoplasms. CONCLUSION: The incidence of secondary onset of second neoplasms in children with malignant solid tumors is not high, considering that this is correlated to the use of alkylating agents, topoisomerase II inhibitors, platinum-based chemotherapy drugs and radiotherapy, and associated with the chromosomal abnormalities of children. KEY WORDS: Chemotherapy, Children, Radiotherapy, Second malignant neoplasm, Solid tumor.

Long-term Follow-up of Detaenial Sigmoid Neobladder Reconstruction for Paediatric Patients with Bladder and Prostate Rhabdomyosarcoma: Technique and Results from a Single High-volume Centre.

BACKGROUND: Rhabdomyosarcoma (RMS) is the most common paediatric soft-tissue sarcoma. Approximately 15-20% of RMS cases arise from the bladder and prostate (B/P). The optimal treatment strategy for B/P RMS remains unclear. OBJECTIVE: To retrospectively evaluate the applicability of our procedure performed to treat paediatric patients with B/P RMS. DESIGN, SETTING, AND PARTICIPANTS: This is a retrospective analysis from a single tertiary referral hospital. From August 2003 to March 2021, 62 children pathologically diagnosed with B/P RMS underwent radical cystectomy and orthotopic detaenial sigmoid neobladder reconstruction in our centre. SURGICAL PROCEDURE: Surgical procedures included laparoscopic radical cystectomy and detaenial sigmoid neobladder reconstruction, which is demonstrated in the accompanying video. MEASUREMENTS: Demographic, clinical, and follow-up data were collected. Perioperative and long-term oncological and functional outcomes were reported. A logistic regression analysis was also performed. RESULTS AND LIMITATIONS: All surgeries, including three intracorporeal laparoscopic surgeries, were completed successfully. Of the 62 patients, 54 were alive without evidence of disease recurrence or metastasis at the last follow-up. Five of the 14 >12-yr-old boys reported that they experienced erections. Two female patients >12 yr old reported that they menstruated. However, this was a retrospective study conducted at a single centre with limited surgeon experience. CONCLUSIONS: Our results confirmed the safety and feasibility of primary orthotopic sigmoid neobladder reconstruction after radical cystectomy for paediatric patients with B/P RMS. Good outcomes in terms of oncological control and functional recovery were achieved. The high histocompatibility and tissue adaptability of children are inspiring. PATIENT SUMMARY: We describe our stepwise technique of radical cystectomy and detaenial sigmoid neobladder reconstruction for paediatric patients with bladder and prostate rhabdomyosarcoma. With this technique, we were able to achieve good functional recovery without compromising cancer control and significantly increasing complications.

Dickkopf-1 Inhibition Reactivates Wnt/ß-Catenin Signaling in Rhabdomyosarcoma, Induces Myogenic Markers In Vitro and Impairs Tumor Cell Survival In Vivo.

The Wnt/ß-catenin signaling pathway plays a pivotal role during embryogenesis and its deregulation is a key mechanism in the origin and progression of several tumors. Wnt antagonists have been described as key modulators of Wnt/ß-catenin signaling in cancer, with Dickkopf-1 (DKK-1) being the most studied member of the DKK family. Although the therapeutic potential of DKK-1 inhibition has been evaluated in several diseases and malignancies, little is known in pediatric tumors. Only a few works have studied the genetic inhibition and function of DKK-1 in rhabdomyosarcoma. Here, for the first time, we report the analysis of the therapeutic potential of DKK-1 pharmaceutical inhibition in rhabdomyosarcoma, the most common soft tissue sarcoma in children. We performed DKK-1 inhibition via shRNA technology and via the chemical inhibitor WAY-2626211. Its inhibition led to ß-catenin activation and the modulation of focal adhesion kinase (FAK), with positive effects on in vitro expression of myogenic markers and a reduction in proliferation and invasion. In addition, WAY-262611 was able to impair survival of tumor cells in vivo. Therefore, DKK-1 could constitute a molecular target, which could lead to novel therapeutic strategies in RMS, especially in those patients with high DKK-1 expression.

Methylation profiling reveals novel molecular classes of rhabdomyosarcoma.

Rhabdomyosarcomas (RMS) represent a family of aggressive soft tissue sarcomas that present in both children and adults. Pathologic risk stratification for RMS has been based on histologic subtype, with poor outcomes observed in alveolar rhabdomyosarcoma (ARMS) and the adult-type pleomorphic rhabdomyosarcoma (PRMS) compared to embryonal rhabdomyosarcoma (ERMS). Genomic sequencing studies have expanded the spectrum of RMS, with several new molecularly defined entities, including fusion-driven spindle cell/sclerosing rhabdomyosarcoma (SC/SRMS) and MYOD1-mutant SC/SRMS. Comprehensive genomic analysis has previously defined the mutational and copy number spectrum for the more common ERMS and ARMS and revealed corresponding methylation signatures. Comparatively, less is known about epigenetic correlates for the rare SC/SRMS or PRMS histologic subtypes. Herein, we present exome and RNA sequencing, copy number analysis, and methylation profiling of the largest cohort of molecularly characterized RMS samples to date. In addition to ARMS and ERMS, we identify two novel methylation subtypes, one having SC/SRMS histology and defined by MYOD1 p. L122R mutations and the other matching adult-type PRMS. Selected tumors from adolescent patients grouped with the PRMS methylation class, expanding the age range of these rare tumors. Limited follow-up data suggest that pediatric tumors with MYOD1-mutations are associated with an aggressive clinical course.

SNAI2-Mediated Repression of BIM Protects Rhabdomyosarcoma from Ionizing Radiation.

Ionizing radiation (IR) and chemotherapy are mainstays of treatment for patients with rhabdomyosarcoma, yet the molecular mechanisms that underlie the success or failure of radiotherapy remain unclear. The transcriptional repressor SNAI2 was previously identified as a key regulator of IR sensitivity in normal and malignant stem cells through its repression of the proapoptotic BH3-only gene PUMA/BBC3. Here, we demonstrate a clear correlation between SNAI2 expression levels and radiosensitivity across multiple rhabdomyosarcoma cell lines. Modulating SNAI2 levels in rhabdomyosarcoma cells through its overexpression or knockdown altered radiosensitivity in vitro and in vivo. SNAI2 expression reliably promoted overall cell growth and inhibited mitochondrial apoptosis following exposure to IR, with either variable or minimal effects on differentiation and senescence, respectively. Importantly, SNAI2 knockdown increased expression of the proapoptotic BH3-only gene BIM, and chromatin immunoprecipitation sequencing experiments established that SNAI2 is a direct repressor of BIM/BCL2L11. Because the p53 pathway is nonfunctional in the rhabdomyosarcoma cells used in this study, we have identified a new, p53-independent SNAI2/BIM signaling axis that could potentially predict clinical responses to IR treatment and be exploited to improve rhabdomyosarcoma therapy. SIGNIFICANCE: SNAI2 is identified as a major regulator of radiation-induced apoptosis in rhabdomyosarcoma through previously unknown mechanisms independent of p53.

Negative correlation of single-cell PAX3:FOXO1 expression with tumorigenicity in rhabdomyosarcoma.

Rhabdomyosarcomas (RMS) are phenotypically and functionally heterogeneous. Both primary human RMS cultures and low-passage Myf6Cre,Pax3:Foxo1,p53 mouse RMS cell lines, which express the fusion oncoprotein Pax3:Foxo1 and lack the tumor suppressor Tp53 (Myf6Cre,Pax3:Foxo1,p53), exhibit marked heterogeneity in PAX3:FOXO1 (P3F) expression at the single cell level. In mouse RMS cells, P3F expression is directed by the Pax3 promoter and coupled to eYFP YFPlow/P3Flow mouse RMS cells included 87% G0/G1 cells and reorganized their actin cytoskeleton to produce a cellular phenotype characterized by more efficient adhesion and migration. This translated into higher tumor-propagating cell frequencies of YFPlow/P3Flow compared with YFPhigh/P3Fhigh cells. Both YFPlow/P3Flow and YFPhigh/P3Fhigh cells gave rise to mixed clones in vitro, consistent with fluctuations in P3F expression over time. Exposure to the anti-tropomyosin compound TR100 disrupted the cytoskeleton and reversed enhanced migration and adhesion of YFPlow/P3Flow RMS cells. Heterogeneous expression of PAX3:FOXO1 at the single cell level may provide a critical advantage during tumor progression.

Case-control study of paternal occupational exposures and childhood bone tumours and soft-tissue sarcomas in Great Britain, 1962-2010.

BACKGROUND: This nationwide study investigated associations between paternal occupational exposure and childhood bone tumours and soft- tissue sarcomas. METHODS: The UK National Registry of Childhood Tumours provided cases of childhood sarcomas born and diagnosed in Great Britain, 1962-2010. Control births, unaffected by childhood cancer, were matched on sex, birth period and birth registration sub-district. Fathers' occupations were assigned to one or more of 33 exposure groups and coded for occupational social class. RESULTS: We analysed 5,369 childhood sarcoma cases and 5380 controls. Total bone tumours, total soft-tissue sarcomas and the subgroups osteosarcoma, rhabdomyosarcoma and Ewing Sarcoma Family of Tumours (ESFT) were considered separately. Significant positive associations were seen between rhabdomyosarcoma and paternal exposure to EMFs (odds ratio = 1.67, CI = 1.22-2.28) and also for ESFT and textile dust (1.93, 1.01-3.63). There were putative protective effects on total bone tumours of paternal dermal exposure to hydrocarbons, metal, metal working or oil mists. CONCLUSIONS: Despite the large size and freedom from bias of this study, our results should be interpreted with caution. Many significance tests were undertaken, and chance findings are to be expected. Nevertheless, our finding of associations between ESFT and paternal exposure to textile dust may support related suggestions in the literature.

Refinement of risk stratification for childhood rhabdomyosarcoma using FOXO1 fusion status in addition to established clinical outcome predictors: A report from the Children's Oncology Group.

BACKGROUND: Previous studies of the prognostic importance of FOXO1 fusion status in patients with rhabdomyosarcoma (RMS) have had conflicting results. We re-examined risk stratification by adding FOXO1 status to traditional clinical prognostic factors in children with localized or metastatic RMS. METHODS: Data from six COG clinical trials (D9602, D9802, D9803, ARST0331, ARTS0431, ARST0531; two studies each for low-, intermediate- and high-risk patients) accruing previously untreated patients with RMS from 1997 to 2013 yielded 1727 evaluable patients. Survival tree regression for event-free survival (EFS) was conducted to recursively select prognostic factors for branching and split. Factors included were age, FOXO1, clinical group, histology, nodal status, number of metastatic sites, primary site, sex, tumor size, and presence of metastases in bone/bone marrow, soft tissue, effusions, lung, distant lymph nodes, and other sites. Definition and outcome of the proposed risk groups were compared to existing systems and cross-validated results. RESULTS: The 5-year EFS and overall survival (OS) for evaluable patients were 69% and 79%, respectively. Extent of disease (localized versus metastatic) was the first split (EFS 73% vs 30%; OS 84% vs. 42%). FOXO1 status (positive vs negative) was significant in the second split both for localized (EFS 52% vs 78%; OS 65% vs 88%) and metastatic disease (EFS 6% vs 46%; OS 19% vs 58%). CONCLUSIONS: After metastatic status, FOXO1 status is the most important prognostic factor in patients with RMS and improves risk stratification of patients with localized RMS. Our findings support incorporation of FOXO1 status in risk stratified clinical trials.

Muscle Stem Cells Give Rise to Rhabdomyosarcomas in a Severe Mouse Model of Duchenne Muscular Dystrophy.

Most human cancers originate from high-turnover tissues, while low-proliferating tissues, like skeletal muscle, exhibit a lower incidence of tumor development. In Duchenne muscular dystrophy (DMD), which induces increased skeletal muscle regeneration, tumor incidence is increased. Rhabdomyosarcomas (RMSs), a rare and aggressive type of soft tissue sarcoma, can develop in this context, but the impact of DMD severity on RMS development and its cell of origin are poorly understood. Here, we show that RMS latency is affected by DMD severity and that muscle stem cells (MuSCs) can give rise to RMS in dystrophic mice. We report that even before tumor formation, MuSCs exhibit increased self-renewal and an expression signature associated with RMSs. These cells can form tumorspheres in vitro and give rise to RMSs in vivo. Finally, we show that the inflammatory genes Ccl11 and Rgs5 are involved in RMS growth. Together, our results show that DMD severity drives MuSC-mediated RMS development.

Combined Sclerosing and Spindle Cell Rhabdomyosarcoma in Previous Craniotomy Site: A Case Report and a Review of the Literature.

Sclerosing rhabdomyosarcoma (RMS) is a rare subtype of RMS with unique prominent stromal hyalinization and a pseudovascular architecture. It overlaps morphologically with spindle cell RMS and poses both diagnostic and therapeutic challenges because of its rarity and aggressive clinical course. In this article, we report a case of sclerosing RMS arising from a prior craniotomy site, which demonstrated both sclerosing and spindle cell components. A literature review of RMS with sclerosing morphology identified 122 cases. Our review documents the following: sclerosing RMS occurs in both childhood and adult populations, has a predilection for the head and neck areas, and has a worse prognosis in adults. Sclerosing RMS harbors a high frequency of MYOD1 mutations, conferring a poor clinical outcome. Sclerosing RMS and spindle RMS likely represent a morphologic spectrum of one entity.

RAGE in the pathophysiology of skeletal muscle.

Emerging evidence suggests that the signalling of the Receptor for Advanced Glycation End products (RAGE) is critical for skeletal muscle physiology controlling both the activity of muscle precursors during skeletal muscle development and the correct time of muscle regeneration after acute injury. On the other hand, the aberrant re-expression/activity of RAGE in adult skeletal muscle is a hallmark of muscle wasting that occurs in response to ageing, genetic disorders, inflammatory conditions, cancer, and metabolic alterations. In this review, we discuss the mechanisms of action and the ligands of RAGE involved in myoblast differentiation, muscle regeneration, and muscle pathological conditions. We highlight potential therapeutic strategies for targeting RAGE to improve skeletal muscle function.

Targeted Therapy-based Combination Treatment in Rhabdomyosarcoma.

Targeted therapies have revolutionized cancer treatment; however, progress lags behind in alveolar (ARMS) and embryonal rhabdomyosarcoma (ERMS), a soft-tissue sarcoma mainly occurring at pediatric and young adult age. Insulin-like growth factor 1 receptor (IGF1R)-directed targeted therapy is one of the few single-agent treatments with clinical activity in these diseases. However, clinical effects only occur in a small subset of patients and are often of short duration due to treatment resistance. Rational selection of combination treatments of either multiple targeted therapies or targeted therapies with chemotherapy could hypothetically circumvent treatment resistance mechanisms and enhance clinical efficacy. Simultaneous targeting of distinct mechanisms might be of particular interest in this regard, as this affects multiple hallmarks of cancer at once. To determine the most promising and clinically relevant targeted therapy-based combination treatments for ARMS and ERMS, we provide an extensive overview of preclinical and (early) clinical data concerning a variety of targeted therapy-based combination treatments. We concentrated on the most common classes of targeted therapies investigated in rhabdomyosarcoma to date, including those directed against receptor tyrosine kinases and associated downstream signaling pathways, the Hedgehog signaling pathway, apoptosis pathway, DNA damage response, cell-cycle regulators, oncogenic fusion proteins, and epigenetic modifiers. Mol Cancer Ther; 17(7); 1365-80. ©2018 AACR.

Immunohistochemical Characterization of Sarcomas in Trp53+/- Haploinsufficient Mice.

The use of immunohistochemical (IHC) staining in determining and/or confirming the cellular origin of poorly differentiated sarcomas was evaluated in this study. Sarcomatous neoplasms were evaluated in a research study conducted in 2 strains of p53+/- haploinsufficient mice. The most common neoplasms were undifferentiated sarcomas, followed by osteosarcomas and rhabdomyosarcomas (RMSs). The RMSs were poorly differentiated and appeared similar to the pleomorphic, or adult type, RMS of humans. All sarcomas stained positive by IHC for the mesenchymal cell intermediate filament vimentin. The RMSs were identified by positive IHC staining for myogenin, a transcription factor specific to skeletal muscle. Osteosarcomas were easily identifiable on hematoxylin and eosin-stained slides; no generally accepted IHC stain specific for bone is presently available. Some of the undifferentiated sarcomas contained numerous macrophages that stained positive for F4/80, a macrophage marker; the positive-staining cells were considered to be infiltrating macrophages. One-third of the neoplasms observed in this study were associated with subcutaneous implanted electronic microchips used for animal identification. Based upon histopathologic evaluation and IHC staining, it was not possible to distinguish neoplasms associated with subcutaneous microchips from neoplasms not associated with microchips.

Malformación adenomatoidea quística y riesgo de tumores malignos pulmonares / Adenomatoid lung malformation and malignant tumors

Cystic adenomatoid malformation is the most frequent congenital pulmonary malformation. The usual treatment is surgical resection. However there is controversy over management in asymptomatic patients. The possible malignization would justify surgery of cystic lesions. Relation with pleuropulmonary blastoma has been described, however it is not clear whether this is a primary tumor or cyst malignization. Cystic adenomatoid malformation also has association with adenocarcinoma and rhabdomyosarcoma. Currently available evidence suggests surgical resection, despite the natural course of congenital lung cystic lesions is uncertain

La malformación adenomatoidea quística (MAQ) es la anomalía del desarrollo pulmonar más frecuente. El tratamiento habitual es la resección quirúrgica, no obstante existe controversia sobre el manejo en pacientes asintomáticos. La posible malignización de las lesiones quísticas es uno de los argumentos que justifican la cirugía en estos pacientes. Se ha descrito relación con blastoma pleuropulmonar, sin embargo no está claro si se trataría de una lesión quística que se maligniza o es una entidad diferente. También hay asociación con adenocarcinoma y rabdomiosarcoma . Actualmente se sugiere la resección quirúrgica como el tratamiento más adecuado, sin embargo la evolución natural de las lesiones quísticas pulmonares congénitas es incierta

Deep Sequencing Reveals a Novel miR-22 Regulatory Network with Therapeutic Potential in Rhabdomyosarcoma.

Current therapeutic options for the pediatric cancer rhabdomyosarcoma have not improved significantly, especially for metastatic rhabdomyosarcoma. In the current work, we performed a deep miRNA profiling of the three major human rhabdomyosarcoma subtypes, along with cell lines and normal muscle, to identify novel molecular circuits with therapeutic potential. The signature we determined could discriminate rhabdomyosarcoma from muscle, revealing a subset of muscle-enriched miRNA (myomiR), including miR-22, which was strongly underexpressed in tumors. miR-22 was physiologically induced during normal myogenic differentiation and was transcriptionally regulated by MyoD, confirming its identity as a myomiR. Once introduced into rhabdomyosarcoma cells, miR-22 decreased cell proliferation, anchorage-independent growth, invasiveness, and promoted apoptosis. Moreover, restoring miR-22 expression blocked tumor growth and prevented tumor dissemination in vivo Gene expression profiling analysis of miR-22-expressing cells suggested TACC1 and RAB5B as possible direct miR-22 targets. Accordingly, loss- and gain-of-function experiments defined the biological relevance of these genes in rhabdomyosarcoma pathogenesis. Finally, we demonstrated the ability of miR-22 to intercept and overcome the intrinsic resistance to MEK inhibition based on ERBB3 upregulation. Overall, our results identified a novel miR-22 regulatory network with critical therapeutic implications in rhabdomyosarcoma. Cancer Res; 76(20); 6095-106. ©2016 AACR.

Combined chemical-genetic approach identifies cytosolic HSP70 dependence in rhabdomyosarcoma.

Cytosolic and organelle-based heat-shock protein (HSP) chaperones ensure proper folding and function of nascent and injured polypeptides to support cell growth. Under conditions of cellular stress, including oncogenic transformation, proteostasis components maintain homeostasis and prevent apoptosis. Although this cancer-relevant function has provided a rationale for therapeutically targeting proteostasis regulators (e.g., HSP90), cancer-subtype dependencies upon particular proteostasis components are relatively undefined. Here, we show that human rhabdomyosarcoma (RMS) cells, but not several other cancer cell types, depend upon heat-shock protein 70 kDA (HSP70) for survival. HSP70-targeted therapy (but not chemotherapeutic agents) promoted apoptosis in RMS cells by triggering an unfolded protein response (UPR) that induced PRKR-like endoplasmic reticulum kinase (PERK)-eukaryotic translation initiation factor α (eIF2α)-CEBP homologous protein (CHOP) signaling and CHOP-mediated cell death. Intriguingly, inhibition of only cytosolic HSP70 induced the UPR, suggesting that the essential activity of HSP70 in RMS cells lies at the endoplasmic reticulum-cytosol interface. We also found that increased CHOP mRNA in clinical specimens was a biomarker for poor outcomes in chemotherapy-treated RMS patients. The data suggest that, like human epidermal growth factor receptor 2 (HER2) amplification in breast cancer, increased CHOP in RMS is a biomarker of decreased response to chemotherapy but enhanced response to targeted therapy. Our findings identify the cytosolic HSP70-UPR axis as an unexpected regulator of RMS pathogenesis, revealing HSP70-targeted therapy as a promising strategy to engage CHOP-mediated apoptosis and improve RMS treatment. Our study highlights the utility of dissecting cancer subtype-specific dependencies on proteostasis networks to uncover unanticipated cancer vulnerabilities.

The Role of Childhood Infections and Immunizations on Childhood Rhabdomyosarcoma: A Report From the Children's Oncology Group.

BACKGROUND: Rhabdomyosarcoma (RMS) is a rare, highly malignant tumor arising from primitive mesenchymal cells that differentiate into skeletal muscle. Relatively little is known about RMS susceptibility. Based on growing evidence regarding the role of early immunologic challenges on RMS development, we evaluated the role of infections and immunizations on this clinically significant pediatric malignancy. PROCEDURE: RMS cases (n = 322) were enrolled from the third trial coordinated by the Intergroup Rhabdomyosarcoma Study Group. Population-based controls (n = 322) were pair matched to cases on race, sex, and age. The following immunizations were assessed: diphtheria, pertussis, and tetanus (DPT); measles, mumps, and rubella; and oral polio vaccine. We also evaluated if immunizations were complete versus incomplete. We examined selected infections including chickenpox, mumps, pneumonia, scarlet fever, rubella, rubeola, pertussis, mononucleosis, and lung infections. Conditional logistic regression models were used to calculate an odds ratio (OR) and 95% confidence interval (CI) for each exposure, adjusted for maternal education and total annual income. RESULTS: Incomplete immunization schedules (OR = 5.30, 95% CI: 2.47-11.33) and incomplete DPT immunization (OR = 1.56, 95% CI: 1.06-2.29) were positively associated with childhood RMS. However, infections did not appear to be associated with childhood RMS. CONCLUSIONS: This is the largest study of RMS to date demonstrating a possible protective effect of immunizations against the development of childhood RMS. Further studies are needed to validate our findings. Our findings add to the growing body of literature, suggesting a protective role of routine vaccinations in childhood cancer and specifically in childhood RMS.

Neurofibromatosis type 1 and malignancy in childhood.

Neurofibromatosis type 1 (NF1) is an autosomal dominant hereditary neurocutaneous syndrome characterized by multi-system involvement and an increased incidence of both benign and malignant tumors. In this study, we evaluated the clinical presentation and prognosis of NF1 and malignancy. Between 1975 and 2013, 26 (5%) of the 473 patients with NF1 at our center developed non-neurofibroma neoplasms. The patient files of 26 subjects with tumors, other than optic glioma, were analyzed retrospectively to evaluate clinical features and treatment results. The age at diagnosis of NF1 ranged from 3 months to 16 years (median 5.5 years). The age range at tumor diagnosis was 1.5-33 years (median 8 years) in these 26 patients. The tumor histological subtypes included the following: 12 soft-tissue tumors (6 malignant peripheral nerve sheath tumors (MPNST), 5 rhabdomyosarcomas (RMS) and 1 malignant fibrous histiocytoma), 11 brain tumors (6 low-grade gliomas, 3 high-grade gliomas, and 2 medulloblastoma), 2 neuroblastomas and 1 non-Hodgkin's lymphoma. Twelve of 26 patients were alive at the time of the study. Although benign brain tumors with NF1 are more common, high-grade brain tumors also occur. Thus, careful and regular follow-up is crucial for early detection of malignancy in NF1 patients.