SALL4 and C-kit positive malignant extrarenal rhabdoid tumor of the pelvis in a child: A diagnostic and therapeutic challenge.

ABSTRACT: Extrarenal rhabdoid tumors (ERRTs) are highly aggressive pediatric tumors with very few cases reported in the literature. These tumors, similar to their renal counterparts, are characterized by inactivating mutations of the SMARCB1/INI-1 gene, a member of the SWI/SNF chromatin remodeling pathway. Diagnosis of ERRTs appears challenging owing to its rarity, varied morphological profile with a higher tendency for rhabdoid differentiation, and overlapping features with other SMARCB-1 deficient tumors. Here, we report a case of ERRT in the pelvis of a three-year-old child with an unusual expression of SALL4 and C-kit on immunohistochemistry. A complete immunohistochemical workup might help in differentiating ERRTs from other SMARCB1/INI1-deficient soft tissue tumors. The expression of stem cell markers in the presented case also suggests that these tumors might originate from or share similarities with embryonic stem cells or germ cells.

[Pediatric soft tissue tumors : Tumors of uncertain origin]. / Kindliche Weichteiltumoren : Tumoren unklaren Ursprungs.

Soft tissue tumors of childhood are an extremely heterogeneous group of tumors that require precise diagnosis for therapy. In this article, selected tumors of uncertain origin that exhibit characteristic histological, immunophenotypical, and molecular features are addressed. Angiomatoid fibrous histiocytoma, alveolar soft part sarcoma, extrarenal rhabdoid tumor, synovial sarcoma, and desmoplastic small round cell tumor differ in their pathology, their clinical behavior, and prognosis.

Inhibiting EZH2 targets atypical teratoid rhabdoid tumor by triggering viral mimicry via both RNA and DNA sensing pathways.

Inactivating mutations in SMARCB1 confer an oncogenic dependency on EZH2 in atypical teratoid rhabdoid tumors (ATRTs), but the underlying mechanism has not been fully elucidated. We found that the sensitivity of ATRTs to EZH2 inhibition (EZH2i) is associated with the viral mimicry response. Unlike other epigenetic therapies targeting transcriptional repressors, EZH2i-induced viral mimicry is not triggered by cryptic transcription of endogenous retroelements, but rather mediated by increased expression of genes enriched for intronic inverted-repeat Alu (IR-Alu) elements. Interestingly, interferon-stimulated genes (ISGs) are highly enriched for dsRNA-forming intronic IR-Alu elements, suggesting a feedforward loop whereby these activated ISGs may reinforce dsRNA formation and viral mimicry. EZH2i also upregulates the expression of full-length LINE-1s, leading to genomic instability and cGAS/STING signaling in a process dependent on reverse transcriptase activity. Co-depletion of dsRNA sensing and cytoplasmic DNA sensing completely rescues the viral mimicry response to EZH2i in SMARCB1-deficient tumors.

Direct Administration of Chemotherapy and Other Agents into the Fourth Ventricle to Treat Recurrent Malignant Brain Tumors in Children.

Direct administration of chemotherapy and other agents into the fourth ventricle of the brain is a novel approach to treating recurrent malignant posterior fossa brain tumors in children. Candidates for this treatment approach include patients with recurrent medulloblastoma, ependymoma, atypical teratoid/rhabdoid tumor, and potentially other neoplasms that originate in the fourth ventricle or elsewhere in the posterior fossa. In this chapter, the authors first explain the rationale for considering fourth ventricular drug infusions in patients with recurrent malignant posterior fossa tumors. We then summarize the results of translational experiments conducted in piglets and non-human primates that demonstrated safety and favorable pharmacokinetics. These translational experiments led to several pilot human clinical trials, and the results of these trials are reviewed. Finally, currently open clinical trials testing infusion of various agents into the fourth ventricle are discussed, and thoughts about potential future directions are shared.

Decoding pediatric spinal tumors: a single-center retrospective case series on etiology, presentation, therapeutic strategies, and outcomes.

INTRODUCTION: Spinal tumors (ST) often result in dire prognosis, carrying risks such as permanent paralysis, sensory loss, and sphincter dysfunction. Data on their incidence and etiology in pediatric populations are markedly scant. Our study investigates the etiology, clinical manifestation, treatment, and outcomes of pediatric ST. METHODS: We conducted a retrospective review of our institutional pediatric oncology and neurosurgery database, examining 14 patients under 18 years admitted with ST due to oncological diseases since 2005. We analyzed the clinical presentations, evaluations, molecular diagnostics and treatments for these patients. RESULTS: The study spanned 15 years and included 14 pediatric patients, each diagnosed with distinct spinal tumor entity. The mean patient age was approximately 19.6 ± 10.1 months. Severe axial pain along the vertebral column was observed in 13 patients, while acute neurological deterioration manifested in 7 patients. As a first-line intervention, 13 patients underwent decompressive surgery through laminectomy and tumor resection, and only one patient received chemotherapy solely. Before surgery, seven patients were unable to walk; post-surgery, six of them regained their ability to ambulate. The diagnosis encompassed a range of neoplasms: two instances of Ewing sarcoma, 3 instances of teratoma, one case presenting an atypical teratoid Rhabdoid tumor, two instances each of low-grade astrocytoma and neuroblastoma, and single instances of ependymoma, meningioma, rhabdomyosarcoma, and embryonal tumors with multilayered rosettes (ETMRs). Three patients succumbed two years after initiating therapy. CONCLUSION: Despite their rarity, intraspinal tumors in pediatric patients pose substantial therapeutic challenges. The intertwined complexities of the disease entity and the patient's neurological status demand swift initiation of an individualized therapeutic strategy. This crucial step helps optimize outcomes for this patient cohort, who frequently grapple with debilitating health conditions. Inclusion of these patients within a registry is mandatory to optimize treatment outcomes due to their rarity in pediatric population.

Clinical and Molecular Risk Factors in Extracranial Malignant Rhabdoid Tumors: Toward an Integrated Model of High-Risk Tumors.

PURPOSE: Extracranial malignant rhabdoid tumors (eMRT) are a challenging entity. Despite the use of multimodal treatment approaches, therapy failure occurs in 55% to 67% of these. Molecular markers for identification of patients at increased risk for relapse or refractory (R/R) disease are not available. Clinical characteristics may only insufficiently predict the individual course of disease. EXPERIMENTAL DESIGN: Using the EU-RHAB database, we analyzed a cohort of 121 patients with eMRT clinically. For 81 patients, molecular and clinical data were available, which were further complemented with publicly available DNA molecular data from 92 eMRTs. We aimed to delineate molecular risk factors by dissecting the DNA methylome of these tumors. Moreover, we establish clinical characteristics and treatment details of R/R disease in a subcohort of 80 patients. RESULTS: Using consensus hierarchical clustering, we identified three distinct subgroups, one of which (eMRT standard risk) was associated with significantly improved survival, irrespective of germline status and/or localization. At the transcriptome level, this subgroup was characterized by an overexpression of genes involved in muscle development. A relevant proportion of patients developed distant relapses or progressions; the median time to the event was 4 months, underlining the need for early identification and risk stratification of R/R disease. The overall survival was significantly decreased in patients with progressive disease when compared with relapse cases, and reaching complete remission during salvage therapy provided a survival benefit. CONCLUSIONS: Our analysis of eMRT in this comprehensive cohort provides novel insights into the patterns of relapse and integrates molecular and clinical risk factors to guide clinical decision-making.

Gemcitabine therapeutically disrupts essential SIRT1-mediated p53 repression in atypical teratoid/rhabdoid tumors.

Atypical teratoid/rhabdoid tumors (ATRTs) are highly malignant embryonal tumors of the central nervous system with a dismal prognosis. Using a newly developed and validated patient-derived ATRT culture and xenograft model, alongside a panel of primary ATRT models, we found that ATRTs are selectively sensitive to the nucleoside analog gemcitabine. Gene expression and protein analyses indicate that gemcitabine treatment causes the degradation of sirtuin 1 (SIRT1), resulting in cell death through activation of nuclear factor κB (NF-κB) and p53. Furthermore, we discovered that gemcitabine-induced loss of SIRT1 results in a nucleus-to-cytoplasm translocation of the sonic hedgehog (SHH) signaling activator GLI2, explaining the observed additional gemcitabine sensitivity in SHH-subtype ATRT. Treatment of ATRT xenograft-bearing mice with gemcitabine resulted in a >30% increase in median survival and yielded long-term survivors in two independent patient-derived xenograft models. These findings demonstrate that ATRTs are highly sensitive to gemcitabine treatment and may form part of a future multimodal treatment strategy for ATRTs.

Uterine tumors mimicking ovarian sex cord tumors with rhabdoid differentiation: a clinicopathologic study of 4 cases: A case series analysis.

RATIONALE: Uterine tumors resembling ovarian sex cord tumors (UTROSCT) with rhabdoid features are uncommon mesenchymal neoplasms exhibiting diverse histological patterns, including significant rhabdoid morphology. A thorough comprehension of their clinicopathologic features is crucial for precise diagnosis and effective management. PATIENT CONCERNS: This study presents 4 cases of UTROSCT with rhabdoid features, diagnosed in patients aged 31 to 58. Varied recurrence patterns were observed, including similar recurrent lesions to the primary tumors with subsequent mortality, initial invasion and lymph node metastasis, and presence of only primary tumor. DIAGNOSES: Histopathological examination revealed diverse morphological patterns, prominently featuring rhabdoid differentiation. Immunohistochemical analysis showed expression of hormone receptors, sex cord, smooth muscle, and epithelial markers, notably WT1, CD56, and CD99. Molecular analysis identified ESR1-NCOA2 fusions and ESR1 and NCOA2/3 rearrangements, indicating a potential association between these genetic alterations and extensive rhabdoid differentiation. INTERVENTIONS: Various treatments were administered post-recurrence, including chemotherapy and targeted therapies. However, poor clinical outcomes were observed in all cases. OUTCOMES: Despite aggressive treatments, including chemotherapy and targeted therapies, poor clinical outcomes were observed, highlighting the aggressive nature of UTROSCT with significant rhabdoid differentiation. LESSONS: This case series emphasizes the importance of detailed pathological reporting, comprehensive molecular testing, and thorough tumor staging in UTROSCT cases with rhabdoid features. Enhanced understanding of the clinicopathologic characteristics of UTROSCT with rhabdoid differentiation is crucial for accurate diagnosis, prognostication, and management strategies.

Clinical protocol phase II study of tumor infiltrating lymphocytes in advanced tumors with alterations in the SWI/SNF complex: the TILTS study.

The SWI/SNF complex is a chromatin remodeling complex comprised by several proteins such as SMARCA4 or SMARCB1. Mutations in its components can lead to the development of aggressive rhabdoid tumors such as epithelioid sarcoma, malignant rhabdoid tumor or small cell carcinoma of the ovary hypercalcemic type, among others. These malignancies tend to affect young patients and their prognosis is poor given the lack of effective treatments. Characteristically, these tumors are highly infiltrated by TILs, suggesting that some lymphocytes are recognizing tumor antigens. The use of those TILs as a therapeutic strategy is a promising approach worth exploring. Here, we report the clinical protocol of the TILTS study, a Phase II clinical trial assessing personalized adoptive cell therapy with TILs in patients affected by these tumor types.Clinical Trial Registration: 2023-504632-17-00 (www.clinicaltrialsregister.eu) (ClinicalTrials.gov).

[Box: see text].

Malignant Rhabdoid Tumor and Related Pediatric Tumors: Multimodality Imaging Review with Pathologic Correlation.

Malignant rhabdoid tumors (MRTs) are rare but lethal solid neoplasms that overwhelmingly affect infants and young children. While the central nervous system is the most common site of occurrence, tumors can develop at other sites, including the kidneys and soft tissues throughout the body. The anatomic site of involvement dictates tumor nomenclature and nosology. While the clinical and imaging manifestations of MRTs and other more common entities may overlap, there are some site-specific distinctive imaging characteristics. Irrespective of the site of occurrence, somatic and germline mutations in SMARCB1, and rarely in SMARCA4, underlie the entire spectrum of rhabdoid tumors. MRTs have a simple and remarkably stable genome but can demonstrate considerable molecular and biologic heterogeneity. Related neoplasms encompass an expanding category of phenotypically dissimilar (nonrhabdoid tumors driven by SMARC-related alterations) entities. US, CT, MRI, and fluorodeoxyglucose PET/CT or PET/MRI facilitate diagnosis, initial staging, and follow-up, thus informing therapeutic decision making. Multifocal synchronous or metachronous rhabdoid tumors occur predominantly in the context of underlying rhabdoid tumor predisposition syndromes (RTPSs). These autosomal dominant disorders are driven in most cases by pathogenic variants in SMARCB1 (RTPS type 1) and rarely by pathogenic variants in SMARCA4 (RTPS type 2). Genetic testing and counseling are imperative in RTPS. Guidelines for imaging surveillance in cases of RTPS are based on age at diagnosis. ©RSNA, 2024 Supplemental material is available for this article.

NRP1 knockdown inhibits the invasion and migration of rhabdoid tumor of the kidney cells.

PURPOSE: The aim of this study was to detect candidate oncogenes of rhabdoid tumor of the kidney (RTK) and evaluate their roles in RTK in vitro. METHODS: An integrated analysis of messenger RNA (mRNA) and microRNA (miRNA) sequencing was performed to determine the expression profile of exosome-derived miRNAs and mRNAs in human RTK-derived cell lines and a human embryonic renal cell line. A Gene Ontology enrichment analysis was performed to analyze the functional characteristics of differentially expressed mRNAs in RTK cells. Matrigel invasion and wound-healing assays were performed to evaluate the cell invasion and migration abilities. RESULTS: Forty mRNAs were highly expressed in RTK cells targeted by exosomal miRNAs, the expression of which was lower in RTK cells than in the controls. These mRNAs were primarily related to cell adhesion. Of these mRNAs, we selected neuropilin 1 (NRP1) as a candidate oncogene because its upregulated expression is associated with a poor prognosis of several types of tumors. RTK cells in which NRP1 had been knocked down exhibited decreased invasive and migratory abilities. CONCLUSION: Our study indicates that NRP1 acts as an oncogene by promoting the invasion and migration of RTK cells and that it could serve as a therapeutic target.

PHF6 cooperates with SWI/SNF complexes to facilitate transcriptional progression.

Genes encoding subunits of SWI/SNF (BAF) chromatin remodeling complexes are mutated in nearly 25% of cancers. To gain insight into the mechanisms by which SWI/SNF mutations drive cancer, we contributed ten rhabdoid tumor (RT) cell lines mutant for SWI/SNF subunit SMARCB1 to a genome-scale CRISPR-Cas9 depletion screen performed across 896 cell lines. We identify PHF6 as specifically essential for RT cell survival and demonstrate that dependency on Phf6 extends to Smarcb1-deficient cancers in vivo. As mutations in either SWI/SNF or PHF6 can cause the neurodevelopmental disorder Coffin-Siris syndrome, our findings of a dependency suggest a previously unrecognized functional link. We demonstrate that PHF6 co-localizes with SWI/SNF complexes at promoters, where it is essential for maintenance of an active chromatin state. We show that in the absence of SMARCB1, PHF6 loss disrupts the recruitment and stability of residual SWI/SNF complex members, collectively resulting in the loss of active chromatin at promoters and stalling of RNA Polymerase II progression. Our work establishes a mechanistic basis for the shared syndromic features of SWI/SNF and PHF6 mutations in CSS and the basis for selective dependency on PHF6 in SMARCB1-mutant cancers.

A kinome drug screen identifies multi-TKI synergies and ERBB2 signaling as a therapeutic vulnerability in MYC/TYR subgroup atypical teratoid rhabdoid tumors.

BACKGROUND: Atypical teratoid rhabdoid tumor (ATRT) is a rare, devastating, and largely incurable pediatric brain tumor. Although recent studies have uncovered 3 molecular subgroups of ATRTs with distinct disease patterns, and signaling features, the therapeutic profiles of ATRT subgroups remain incompletely elucidated. METHODS: We examined the effect of 465 kinase inhibitors on a panel of ATRT subgroup-specific cell lines. We then applied multiomics analyses to investigate the underlying molecular mechanism of kinase inhibitor efficacy in ATRT subgroups. RESULTS: We observed that ATRT cell lines are broadly sensitive to inhibitors of the PI3K and MAPK signaling pathways, as well as CDKs, AURKA/B kinases, and polo-like kinase 1. We identified 2 classes of multikinase inhibitors predominantly targeting receptor tyrosine kinases including PDGFR and EGFR/ERBB2 in MYC/TYR ATRT cells. The PDGFRB inhibitor, Dasatinib, synergistically affected MYC/TYR ATRT cell growth when combined with broad-acting PI3K and MAPK pathway inhibitors, including Rapamycin and Trametinib. We observed that MYC/TYR ATRT cells were also distinctly sensitive to various inhibitors of ERBB2 signaling. Transcriptional, H3K27Ac ChIPSeq, ATACSeq, and HiChIP analyses of primary MYC/TYR ATRTs revealed ERBB2 expression, which correlated with differential methylation and activation of a distinct enhancer element by DNA looping. Significantly, we show the brain penetrant EGFR/ERBB2 inhibitor, Afatinib, specifically inhibited in vitro and in vivo growth of MYC/TYR ATRT cells. CONCLUSIONS: Taken together, our studies suggest combined treatments with PDGFR and ERBB2-directed TKIs with inhibitors of the PI3K and MAPK pathways as an important new therapeutic strategy for the MYC/TYR subgroup of ATRTs.

Outcomes for children with recurrent/refractory atypical teratoid rhabdoid tumor: A single-institution study with molecular correlation.

BACKGROUND: Survival data for recurrent pediatric atypical teratoid rhabdoid tumor (ATRT) and its association to molecular groups are extremely limited. METHODS: Single-institution retrospective study of 64 children less than 21 years old with recurrent or treatment-refractory (progressive disease [PD]) ATRT treated at St. Jude Hospital from January 2000 to December 2020. Demographic, clinicopathologic, treatment, molecular grouping (SHH, TYR, and MYC) and germline data were collected. Progression-free survival (PFS2: time from PD to subsequent first progression) and overall survival (OSpostPD: time from PD to death/last follow-up) were estimated by Kaplan-Meier analysis. RESULTS: Median age at and time from initial diagnosis to PD were 2.1 years (range: 0.5-17.9 years) and 5.4 months (range: 0.5-125.6 months), respectively. Only five of 64 children (7.8%) are alive at median follow-up of 10.9 (range: 4.2-18.1) years from PD. The 2/5-year PFS2 and OSpostPD were 3.1% (±1.8%)/1.6% (±1.1%) and 20.3% (±4.8%)/7.3% (±3.5%), respectively. Children with TYR group (n = 10) had a better OSpostPD compared to those with MYC (n = 11) (2-year survival estimates: 60.0% ± 14.3% vs. 18.2% ± 9.5%; p = .019), or those with SHH (n = 21; 4.8% ± 3.3%; p = .014). In univariate analyses, OSpostPD was better with older age at diagnosis (p = .037), female gender (p = .008), and metastatic site of PD compared to local or combined sites of PD (p < .001). Two-year OSpostPD for patients receiving any salvage therapy (n = 39) post PD was 33.3% ± 7.3%. CONCLUSIONS: Children with recurrent/refractory ATRT have dismal outcomes. Older age at diagnosis, female gender, TYR group, and metastatic site of PD were associated with relatively longer survival in our study.

Autologous stem cell transplantation in adults with atypical teratoid rhabdoid tumor: a case report and review.

Aim: Atypical teratoid rhabdoid tumor (ATRT) is a rare and highly aggressive primary CNS neoplasm, predominantly observed in children. The use of autologous stem cell transplantation (ASCT) in pediatric ATRT has shown promise; however, its utility in adult ATRT remains unclear. Patients & methods: This study presents the case of an adult patient with ATRT who is in remission after ASCT and reviews the literature on ASCT in adults with ATRT. Four cases of ATRT in adults who underwent ASCT were identified, with pertinent data summarized. Results: All five patients survived longer than the historical average survival rate, four of whom had no clinical or radiographic evidence of disease at the final follow-up. Conclusion: Based on limited data, there may be a role for ASCT in the treatment of adults with ATRT.

[Box: see text].

Spinal Atypical Teratoid Rhabdoid Tumor in a 14-Year-old Child With Down Syndrome: A Case Report.

Individuals with 21 trisomy or Down syndrome (DS) are known to have an increased risk of acute leukemia, while they rarely develop solid or central nervous system (CNS) tumors. Atypical teratoid rhabdoid tumor (ATRT) is a highly aggressive CNS-WHO grade 4 neoplasm, which has never been reported in association with Down syndrome. We present a case study of a 14-year-old female with Down syndrome, diagnosed with intradural-extramedullary spinal ATRT. The chief complaints included bilateral lower limb weakness, constipation, and urinary incontinence for 2 weeks. Surgery was scheduled, and a biopsy was taken. The histopathology, immunohistochemistry, and molecular analysis confirmed the diagnosis of the ATRT-MYC/group 2B subgroup. This report highlights the challenges of managing a patient with complex medical conditions. Moreover, it adds to the existing literature on CNS tumors in patients with Down syndrome.

SMARCB1 Gene Therapy Using a Novel Tumor-Targeted Nanomedicine Enhances Anti-Cancer Efficacy in a Mouse Model of Atypical Teratoid Rhabdoid Tumors.

Purpose: Atypical teratoid rhabdoid tumor (ATRT) is a deadly, fast-growing form of pediatric brain cancer with poor prognosis. Most ATRTs are associated with inactivation of SMARCB1, a subunit of the chromatin remodeling complex, which is involved in developmental processes. The recent identification of SMARCB1 as a tumor suppressor gene suggests that restoration of SMARCB1 could be an effective therapeutic approach. Methods: We tested SMARCB1 gene therapy in SMARCB1-deficient rhabdoid tumor cells using a novel tumor-targeted nanomedicine (termed scL-SMARCB1) to deliver wild-type SMARCB1. Our nanomedicine is a systemically administered immuno-lipid nanoparticle that can actively cross the blood-brain barrier via transferrin receptor-mediated transcytosis and selectively target tumor cells via transferrin receptor-mediated endocytosis. We studied the antitumor activity of the scL-SMARCB1 nanocomplex either as a single agent or in combination with traditional treatment modalities in preclinical models of SMARCB1-deficient ATRT. Results: Restoration of SMARCB1 expression by the scL-SMARCB1 nanocomplex blocked proliferation, and induced senescence and apoptosis in ATRT cells. Systemic administration of the scL-SMARCB1 nanocomplex demonstrated antitumor efficacy as monotherapy in mice bearing ATRT xenografts, where the expression of exogenous SMARCB1 modulates MYC-target genes. scL-SMARCB1 demonstrated even greater antitumor efficacy when combined with either cisplatin-based chemotherapy or radiation therapy, resulting in significantly improved survival of ATRT-bearing mice. Conclusion: Collectively, our data suggest that restoring SMARCB1 function via the scL-SMARCB1 nanocomplex may lead to therapeutic benefits in ATRT patients when combined with traditional chemoradiation therapies.

Targeting dependency on a paralog pair of CBP/p300 against de-repression of KREMEN2 in SMARCB1-deficient cancers.

SMARCB1, a subunit of the SWI/SNF chromatin remodeling complex, is the causative gene of rhabdoid tumors and epithelioid sarcomas. Here, we identify a paralog pair of CBP and p300 as a synthetic lethal target in SMARCB1-deficient cancers by using a dual siRNA screening method based on the "simultaneous inhibition of a paralog pair" concept. Treatment with CBP/p300 dual inhibitors suppresses growth of cell lines and tumor xenografts derived from SMARCB1-deficient cells but not from SMARCB1-proficient cells. SMARCB1-containing SWI/SNF complexes localize with H3K27me3 and its methyltransferase EZH2 at the promotor region of the KREMEN2 locus, resulting in transcriptional downregulation of KREMEN2. By contrast, SMARCB1 deficiency leads to localization of H3K27ac, and recruitment of its acetyltransferases CBP and p300, at the KREMEN2 locus, resulting in transcriptional upregulation of KREMEN2, which cooperates with the SMARCA1 chromatin remodeling complex. Simultaneous inhibition of CBP/p300 leads to transcriptional downregulation of KREMEN2, followed by apoptosis induction via monomerization of KREMEN1 due to a failure to interact with KREMEN2, which suppresses anti-apoptotic signaling pathways. Taken together, our findings indicate that simultaneous inhibitors of CBP/p300 could be promising therapeutic agents for SMARCB1-deficient cancers.