Abstract BACKGROUND The discovery of unique EP300:BCOR and CREBBP:BCORL1 fusions has extended the spectrum of BCOR altered CNS tumors previously associated with BCOR internal tandem duplication (ITD). Due to the rarity of CNS tumors with BCOR alterations, there is limited information on the clinical outcomes and the effective treatment strategies. METHODS Literature review and retrospective chart analysis RESULTS An 18-year-old male who presented with seizures was found to have a left temporal mass. Histologic diagnosis was low grade glioneural tumor harboring a pathogenic CREBBP:BCOR1 fusion, matching to CNS tumor with EP300:BCOR/BCORL1 fusion by methylation. A re-resection aimed at gross total resection was then performed. Histologic examination revealed residual glioma with focal high-grade transformation, Ki67 up to 35% and CDKN2A loss via FISH analysis. The patient was treated with focal radiation to 54Gy. He remains disease- and seizure-free 1 month post radiation therapy. This case displayed some similarities to previously reported cases, including oligodendroglial- or ependymoma-like features, positivity for Olig2 and/or GFAP, presence of calcifications, and branching capillary networks. However, this case had less frequent mitoses than previously reported cases. In a series of 21 patients with BCOR altered tumors, BCOR-fusion tumor patients had a more favorable PFS compared to BCOR-ITD tumors. In a reported case series of high grade BCOR altered CNS tumors, 5 out of 8 patients remained alive, all of whom received radiation therapy as a primary treatment or at relapse. There is one prior report of an EP300:BCOR tumor undergoing high-grade transformation; increased mitoses, cellularity, and necrosis were observed. This case was lacked necrosis. CONCLUSIONS The optimal treatment for BCOR altered tumors of the CNS is largely unknown given the limited reported cases. Radiation therapy in addition to gross total resection may be an effective treatment leading to more favorable PFS and OS.
Abstract BACKGROUND: Low-grade gliomas (LGG) are the most common solid tumor of childhood and can result in neurologic complications, including seizures, focal neurologic deficits, and learning difficulties. Molecularly targeted agents are increasingly being utilized to treat LGG, but the effect of these agents on accompanying neurologic complications are poorly understood. CASE: An 8-years old male with Neurofibromatosis Type 1 (NF1), medically refractory epilepsy and deep extensive glioma (extending from the optic pathway and involving the basal ganglia and corpus collosum) began selumetinib therapy due to radiographic and symptomatic tumor progression. Radiographic response (resolution of enhancement) was observed at 12 weeks of therapy, accompanied by improvement in seizure frequency, hemiparesis, and academic performance. Due to cardiotoxicity observed at that time (asymptomatic decreased ejection fraction and shortening fraction on echocardiogram), selumetinib was reduced to 50% dosing. On this reduced dose of selumetinib, seizures increased in frequency with subsequent worsening hemiparesis and recurrence of learning difficulties. One month later, dosing was escalated back to 100% due to interval resolution of cardiotoxicity, resulting in resolution of seizures and improvement in focal neurologic deficits and cognition. DISCUSSION: Dose-dependent response to MEK inhibition was observed without concurrent changes in anti-epileptic medications. The tumor was stable in size despite improved enhancement with treatment, suggesting that objective response by RANO criteria is not necessary for improved seizure control in LGG. Recent work has implicated the RAS/MEK/ERK pathway in neuronal precursor cells as a cause for epilepsy, suggesting that MEK inhibition of NF1-heterozygous neurons could be contributing to treatment response in this patient. Improvements in weakness and academic performance may have been due to improved seizure control or a direct effect of MEK inhibition on NF1-heterozygous neurons. CONCLUSION: MEK inhibition may have a clinically relevant anti-seizure effect for patients with pediatric LGG or NF1.
Abstract BACKGROUND: Children with Neurofibromatosis Type 1 (NF1) are at risk for developing gliomas in multiple locations, particularly the optic pathway and brainstem. The goal of this study is to determine if glioma location in NF1 impacts tumor progression and accumulation of neurological deficits over time. METHODS: Retrospective chart review of 98 pediatric patients with NF1-associated gliomas between 1999-2021 at St. Louis Children’s Hospital. Patients who had never received treatment were excluded from analysis. Each glioma was categorized into one of four locations: posterior fossa (PF, n=12, 21%), supratentorial midline (SM, n=33, 57%) supratentorial cortical (SC, n=4, 7%), brainstem (BS, n=9, 15%). Patients with gliomas in different locations had each tumor counted separately (58 total gliomas analyzed). RESULTS: No SC tumors progressed. Time to first progression was comparable across the other 3 locations, and there was no meaningful different in neurologic deficits over time by tumor location. The majority of patients who demonstrated three or more clinical or radiographic progressions had tumors in the SM region. Within the SM tumor group, each tumor was further characterized as a deep extensive glioma (DEG; 36%) or an optic pathway glioma without deep extension (nonDEG; 64%). DEG had a slightly higher number of neurological deficits at baseline (DEG 2.08, nonDEG 1.19), fewer patients with no neurologic deficits (8.3% DEG vs 28.6% nonDEG) and a higher proportion of patients with a first progression event (41% DEG vs 24% nonDEG). However, DEG and nonDEG had similar risk of subsequent progressions after the initial event. CONCLUSION: Among children with NF1 who required glioma treatment, location was not a significant predictor of multiple progression or neurologic morbidity over time. Within the SM location, DEGs represent a newly characterized group that exhibit potentially higher rates of progression and neurological deficits. Multi-institutional analysis is needed to confirm these findings.
Abstract INTRODUCTION: Medulloblastoma is the most common malignant brain tumor in children, with 5-year overall survival (OS) ranging from 60%-95% depending on subgroup and risk status. The POG 8631/CCG 923 trial (accrual 1986-1990) found a 63% 5 year OS for patients with local disease after gross total resection treated with radiation at a dose of 23.4 Gy craniospinal radiation and posterior fossa boost to 54 Gy, vs. 80.5% 5-year OS for patients treated as per full ACNS0331 therapy including maintenance chemotherapy. Herein, we describe a long-term survival with standard-risk medulloblastoma who only received surgical resection and radiation therapy. CASE: A 17-year-old male presented with acute onset of hypertension, bradycardia, headache, and blurry vision and was found to have a heterogeneously enhancing posterior fossa mass with mass effect on the fourth ventricle and hydrocephalus on brain MRI. He underwent gross total resection of the tumor and histopathology revealed medulloblastoma with classic and large cell features. Fluorescence in situ hybridization (FISH) was negative for MYC, MYCN amplification, or HER2 gain. Cerebrospinal fluid cytology was negative for neoplastic cells, and spinal MRI did not reveal any drop metastases. The patient initiated therapy per ACNS0331 with craniospinal irradiation posterior fossa boost. He also received weekly vincristine. After completion of radiation therapy, the family declined further chemotherapy despite medical advice. He had no evidence of relapse most recently at 51 months from completion of therapy. Next generation sequencing and methylation testing are currently pending. CONCLUSION: Current efforts aim at optimizing therapy based on molecular subgrouping, to minimize long-term adverse events associated with current therapies. We report a unique case of an adolescent male with an standard-risk medulloblastoma, who achieved remission with only radiotherapy. Further molecular tumor analysis may elucidate the response of the tumor.
Tamoxifen is widely used to treat estrogen receptor-positive breast cancer. Recent findings that tamoxifen and its derivative 4-hydroxytamoxifen (OHT) can exert estrogen receptor-independent cytotoxic effects have prompted the initiation of clinical trials to evaluate its use in estrogen receptor-negative malignancies. For example, tamoxifen and OHT exert cytotoxic effects in malignant peripheral nerve sheath tumors (MPNST) where estrogen is not involved. In this study, we gained insights into the estrogen receptor-independent cytotoxic effects of OHT by studying how it kills MPNST cells. Although caspases were activated following OHT treatment, caspase inhibition provided no protection from OHT-induced death. Rather, OHT-induced death in MPNST cells was associated with autophagic induction and attenuated by genetic inhibition of autophagic vacuole formation. Mechanistic investigations revealed that OHT stimulated autophagic degradation of K-Ras, which is critical for survival of MPNST cells. Similarly, we found that OHT induced K-Ras degradation in breast, colon, glioma, and pancreatic cancer cells. Our findings describe a novel mechanism of autophagic death triggered by OHT in tumor cells that may be more broadly useful clinically in cancer treatment.
Abstract Background Low-grade gliomas (LGGs) occurring in children can result in many different neurologic complications, including seizures. MEK inhibitors are increasingly being used to treat LGG, but their effect on associated neurologic symptoms has not been established. Results Here, we report a patient with neurofibromatosis type 1 (NF1), medically refractory epilepsy (MRE), and an extensive optic pathway glioma (OPG) who developed dose-dependent seizure control while being treated with selumetinib. Seizure frequency rebounded after dose reduction for cardiac toxicity, then improved, and finally ceased after restarting full dosing, allowing confidence in the cause of improvement. Conclusion Selumetinib may have promise in epilepsy management in other children with NF1 or LGG.
On the Cover: Isolated fibrocytes produce a second wave of connective tissue growth factor (CTGF) in AngII-induced myocardial fibrosis.Purified fibrocytes isolated from the myocardium of AngII-exposed mice demonstrate immunofluorescent staining for the mesenchymal marker COL1 (green) and the hematopoietic marker CD45 (red), with nuclei counterstained with Hoescht stain (blue).
Abstract BACKGROUND The International Pediatric Neuro-Oncology Tumor Board at Washington University in St. Louis School of Medicine (WUSM) was established in January 2021 as a monthly multi-disciplinary collaboration to help guide the care of pediatric central nervous system (CNS) tumor patients worldwide. The quarterly integration of Neurofibromatosis (NF) meetings expanded the initiative in September 2021. This survey explores participant experiences and their satisfaction aiming to optimize this international collaboration. METHODS A cross-sectional survey was distributed via a web-based platform in September 2023 amongst the participating healthcare professionals. RESULTS Fifty-three respondents from 23 countries completed the survey. The majority identified as pediatric hematology-oncologists (59%), and 10% as neuro-oncologists. Ninety-eight percent attended at least one session over two years, and 71% actively engaged in the quarterly NF meetings. Sixty percent attended more than five meetings, and 29% engaged in over 10 meetings. Barriers to attendance were primarily attributed to time constraints (71%) and conflicting professional or personal experiences (27%), while only 7% cited technical limitations and lack of awareness. Ninety-one percent reported that the meetings provide valuable educational insights and knowledge, particularly addressing challenging pediatric neuro-oncology cases. Additionally, 95% acknowledged the tumor board meetings’ positive contribution to professional development. Consensus recommendations emerging from the tumor board were reported to align with institutional recommendations (71%), be clear and comprehensible (93%,) and led to improved outcomes (93%). Notably, meeting frequency, leader expertise, knowledge enhancement, and level of engagement had positive influence on the participants’ willingness to attend the meeting. CONCLUSION Healthcare professionals attending the WUSM International Pediatric Neuro-Oncology Tumor Board reported the effectiveness of this virtual meeting format, its impact on professional development, and the alignment of recommendations with diverse institutional needs. The study provides valuable insights to further enhance the program’s sustainability, international collaboration, and overall effectiveness in improving global pediatric neuro-oncology patient care.
Neurofibromin, the tumor suppressor encoded by the neurofibromatosis type 1 (NF1) gene, potentially suppresses the activation of H-Ras, N-Ras, and K-Ras. However, it is not known whether these classic Ras proteins are hyperactivated in NF1-null nerve sheath tumors, how they contribute to tumorigenesis, and what signaling pathways mediate their effects. Here we show that H-Ras, N-Ras, and K-Ras are coexpressed with their activators (guanine nucleotide exchange factors) in neurofibromin-null malignant peripheral nerve sheath tumor (MPNST) cells, and that all 3 Ras proteins are activated. Dominant negative (DN) H-Ras, a pan-inhibitor of the classic Ras family, inhibited MPNST proliferation and survival, but not migration. However, NF1-null MPNST cells were variably dependent on individual Ras proteins. In some lines, ablation of H-Ras, N-Ras, and/or K-Ras inhibited mitogenesis. In others, ablation of a single Ras protein had no effect on proliferation; in these lines, ablation of a single Ras protein resulted in compensatory increases in the activation and/or expression of other Ras proteins. Using mass spectrometry-based phosphoproteomics, we identified 7 signaling networks affecting morphology, proliferation, and survival that are regulated by DN H-Ras. Thus, neurofibromin loss activates multiple classic Ras proteins that promote proliferation and survival by regulating several distinct signaling cascades.
Abstract BACKGROUND: CNS Germinomas are highly radio-sensitive tumors with an excellent survival rate of more than 90%. The current standard of care combines chemotherapy with reduced-dose radiotherapy to minimize the adverse effects and long-term effects associated with radiotherapy. In the latest Children’s Oncology Group clinical trial (ACNS1123 stratum 2), patients with residual or progressive disease following chemotherapy can be considered for a “second-look” surgery to assess tumor viability. Patients with residual disease who do not undergo second-look surgery receive 24 Gy of whole ventricular radiation with a 12 Gy boost compared to 18 Gy plus boost given to patients in complete remission or without viable tumor on second-look. Conversely, the International Society of Paediatric Oncology (SIOP) protocol does not stratify based on response to chemotherapy, and the Korean SMC GCT trial uses 18 Gy CSI plus boost for all patients regardless of chemotherapy response. METHODS: Single center retrospective chart review of germinoma patients treated at St Louis Children’s Hospital between 2011 and 2021. RESULTS: We analyzed data for all 15 germinoma patients treated between 2011 and 2021. Five patients had residual disease following chemotherapy. Of these five, one had complete remission at the end of radiotherapy, one had partial response, and three had stable disease. All patients remain relapse-free with time of follow-up ranging between 6.3-109.3 months from the end of therapy (median 24 months). CONCLUSION: None of the five patients with residual disease following chemotherapy demonstrated disease progression following chemotherapy and radiotherapy. Future prospective clinical trials are needed in order to test the possibility of treating germinomas patients who have residual disease after chemotherapy with a low dose of radiotherapy similar to that used in patients with complete remission.
