Extracranial rhabdoid tumours: Results of a SFCE series of patients treated with a dose compression strategy according to European Paediatric Soft tisue sarcoma Study Group recommendations

Rhabdoid tumor predisposition syndrome: A historical review of treatments and outcomes for associated pediatric malignancies

Rhabdoid tumor predisposition syndrome (RTPS) is a rare disorder associated with malignant rhabdoid tumor of the kidney (RTK), atypical teratoid rhabdoid tumor (ATRT), and/or other extracranial, extrarenal rhabdoid tumors (EERT), and these pediatric malignancies are difficult to treat. Presently, most of the information regarding clinical manifestations, treatment, and outcomes of rhabdoid tumors comes from large data registries and case series. Our current understanding of treatments for patients with rhabdoid tumors may inform how we approach patients with RTPS. In this manuscript, we review the genetic and clinical features of RTPS and, using known registry data and clinical reports, review associated tumor types ATRT, RTK, and EERT, closing with potential new approaches to treatment. We propose collaborative international efforts to study the use of SMARC (SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin)-targeting agents, high-dose consolidative therapy, and age-based irradiation of disease sites in RTPS.

Soft Tissue Sarcomas in Adolescents and Young Adults

Soft tissue sarcomas (STS) represent a heterogeneous group of extraskeletal mesenchymal tumors that affect individuals throughout the entire age continuum. Despite this pervasive influence, key differences exist in the presentation of these sarcomas across varying age groups that have prevented a more uniform approach to management. Notably, rhabdomyosarcoma (RMS) is more common in children, while most nonrhabdomyosarcoma soft tissue sarcoma (NRSTS) subtypes are more prevalent in adults. Older patients with NRSTS appear to have more molecularly complex biology and often present with more advanced disease compared with children. Poorer outcome disparities are observed in older patients with RMS despite receiving similar treatment as younger patients. In this review, we highlight differences in epidemiology, biology, and management paradigms for pediatric and adult patients with STS and explore opportunities for a unified approach to enhance the care and outcomes within the AYA population.

BKM120 inhibits malignant rhabdoid tumor of the kidney through induction of apoptosis and G0/G1 phase arrest

Malignant rhabdomyosarcoma of the kidney (MRTK) has an inferior prognosis and is insensitive to radiotherapy and chemotherapy. Search for novel, potent medicinal agents is urgent. Herein, data on the gene expression and clinical characteristics of malignant rhabdoid tumors (MRT) were retrieved from the TARGET database. Prognosis-related genes were identified by differential analysis and one-way cox regression analysis, and prognosis-related signalling pathways were identified by enrichment analysis. The prognosis-related genes were imported into the Connectivity Map database for query, and BKM120 was predicted and screened as a potential therapeutic agent for MRTK. A combination of high-throughput RNA sequencing and Western blot verified that the PI3K/Akt signaling pathway is associated with MRTK prognosis and is overactivated in MRTK. Our results outlined that BKM120 inhibited the proliferation, migration, and invasion ability of G401 cells and induced apoptosis and cell cycle G0/G1 phase arrest. In vivo, BKM120 inhibited tumor growth and had no significant toxic side effects. Western blot and immunofluorescence results confirmed that BKM120 could reduce the expression of PI3K and p-AKT, critical proteins of the PI3K/Akt signaling pathway. BKM120 inhibits MRTK by inhibiting PI3K/Akt signalling pathway to induce apoptosis and cell cycle G0/G1 phase arrest, which is anticipated to give the clinical treatment of MRTK a new direction.

The significance of margins in pediatric Non-Rhabdomyosarcoma soft tissue sarcomas: Consensus on surgical margin definition harmonization from the INternational Soft Tissue SaRcoma ConsorTium (INSTRuCT)

BACKGROUND

Margin status following surgery in children, adolescents, and young adults with soft tissue sarcomas is controversial and has been defined differently by various specialties, with definitions changing over time and by cooperative group. The International Soft Tissue Sarcoma Consortium (INSTRuCT) is a collaboration of the Children's Oncology Group (COG) Soft Tissue Sarcoma Committee, European pediatric Soft Tissue sarcoma Study Group (EpSSG), and the European Cooperative Weichteilsarkom Studiengruppe (CWS) devoted to improving patient outcomes by pooling and mining cooperative group clinical trial data.

METHODS

The INSTRuCT non-rhabdomyosarcoma soft tissue sarcoma (NRSTS) working group aimed to develop international harmonized recommendations regarding surgical margin assessment and definitions in children and adolescents with soft tissue tumors.

RESULTS AND CONCLUSION

This review addresses accepted principles and areas of controversy, including the perspectives of surgeons, pathologists, radiation oncologists, and pediatric oncologists, to develop a framework for building common guidelines for future research.

YM155 and chrysin cooperatively suppress survivin expression in SMARCB1/INI1-deficient tumor cells

SMARCB1/INI1 deficiency is seen in several malignant tumors including malignant rhabdoid tumor (MRT), a highly aggressive pediatric malignancy. Loss of SMARCB1/INI1 function alters diverse oncogenic cellular signals, making it difficult to discover effective targeting therapy. By utilizing an in vitro drug screening system, effective therapeutic agents against SMARCB1/INI1-deficient tumors were explored in this study. In the in vitro drug sensitivity test, 80 agents with various actions were screened for their cytotoxicity in a panel of five SMARCB1/INI1-deficient tumor cell lines. The combination effect was screened based on the Bliss independent model. The growth-inhibitory effect was determined in both the conventional two-dimensional culture and the collagen-embedded three-dimensional culture system. Survivin expression after agent exposure was determined by Western blot analysis. All five cell lines were found to be sensitive to YM155, a selective survivin inhibitor. In the drug combination screening, YM155 showed additive to synergistic effects with various agents including chrysin. Chrysin enhanced YM155-induced apoptosis, but not mitochondrial depolarization upon exposure of SMARCB1/INI1-deficient tumor cells to the two agents for 6 h. YM155 and chrysin synergistically suppressed survivin expression, especially in TTN45 cells in which such suppression was observed as early as 6 h after exposure to the two agents. Survivin is suggested to be a therapeutic target in MRT and other SMARCB1/INI1-deficient tumors. Chrysin, a flavone that is widely distributed in plants, cooperatively suppressed survivin expression and enhanced the cytotoxicity of YM155.

Pediatric Non-Rhabdomyosarcoma Soft Tissue Sarcomas: Standard of Care and Treatment Recommendations from the European Paediatric Soft Tissue Sarcoma Study Group (EpSSG)

This paper describes the standard of care for patients with non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) and the therapeutic recommendations developed by the European paediatric Soft tissue sarcoma Study Group (EpSSG). NRSTS form a very mixed group of mesenchymal extraskeletal malignancies. Their rarity, heterogeneity, and aggressiveness make the management of children and adolescents with these tumors complex and challenging. The overall cure rate for patients with NRSTS is around 70%, but survival depends on several prognostic variables, such as histotype and tumor grade, extent of disease and stage, tumor size, and tumor site. While surgery remains the mainstay of treatment for most of these tumors, a multimodal therapeutic approach including radiotherapy and chemotherapy is required in many cases. The EpSSG NRSTS 2005 study was the first prospective protocol tailored specifically to NRSTS. Together with the ARST0332 study developed by the North-American Soft Tissue Sarcoma Committee of the Children's Oncology Group (COG), the EpSSG NRSTS 2005 study currently represents the benchmark for these tumors, establishing risk-adapted standards of care. The EpSSG has developed common treatment recommendations for the large group of adult-type NRSTS (including synovial sarcoma), and specific treatment recommendations for other particular adult-type histologies (ie, alveolar soft-part sarcoma, clear cell sarcoma and dermatofibrosarcoma protuberans); other highly malignant tumors with a biology and clinical behavior differing from those of adult-type NRSTS (ie, rhabdoid tumors and desmoplastic small round cell tumor); and soft tissue tumors of intermediate malignancy (ie desmoid-type fibromatosis, inflammatory myofibroblastic tumors, and infantile fibrosarcoma). New effective drugs are needed for patients whose NRSTS carries the worst prognosis, ie, those with unresectable tumors, metastases at diagnosis, or relapsing disease. Progress in this area relies on our ability to develop international integrated prospective collaborations, both within existing pediatric oncology networks and, importantly, between the communities of specialists treating pediatric and adult sarcoma.