Preoperative 11 C-Methionine PET-MRI in Pediatric Infratentorial Tumors

PURPOSE

MRI is the main imaging modality for pediatric brain tumors, but amino acid PET can provide additional information. Simultaneous PET-MRI acquisition allows to fully assess the tumor and lower the radiation exposure. Although symptomatic posterior fossa tumors are typically resected, the patient management is evolving and will benefit from an improved preoperative tumor characterization. We aimed to explore, in children with newly diagnosed posterior fossa tumor, the complementarity of the information provided by amino acid PET and MRI parameters and the correlation to histopathological results.

PATIENTS AND METHODS

Children with a newly diagnosed posterior fossa tumor prospectively underwent a preoperative 11 C-methionine (MET) PET-MRI. Images were assessed visually and semiquantitatively. Using correlation, minimum apparent diffusion coefficient (ADC min ) and contrast enhancement were compared with MET SUV max . The diameter of the enhancing lesions was compared with metabolic tumoral volume. Lesions were classified according to the 2021 World Health Organization (WHO) classification.

RESULTS

Ten children were included 4 pilocytic astrocytomas, 2 medulloblastomas, 1 ganglioglioma, 1 central nervous system embryonal tumor, and 1 schwannoma. All lesions showed visually increased MET uptake. A negative moderate correlation was found between ADC min and SUV max values ( r = -0.39). Mean SUV max was 3.8 (range, 3.3-4.2) in WHO grade 4 versus 2.5 (range, 1.7-3.0) in WHO grade 1 lesions. A positive moderate correlation was found between metabolic tumoral volume and diameter values ( r = 0.34). There was no correlation between SUV max and contrast enhancement intensity ( r = -0.15).

CONCLUSIONS

Preoperative 11 C-MET PET and MRI could provide complementary information to characterize pediatric infratentorial tumors.

SMARCA4 Loss and Mutated β-Catenin Induce Proliferative Lesions in the Murine Embryonic Cerebellum

Almost all medulloblastomas (MB) of the Wingless/Int-1 (WNT) type are characterized by hotspot mutations in CTNNB1, and mouse models have convincingly demonstrated the tumor-initiating role of these mutations. Additional alterations in SMARCA4 are detected in ∼20% of WNT MB, but their functional role is mostly unknown. We, therefore, amended previously described brain lipid binding protein (Blbp)-cre::Ctnnb1(ex3)fl/wt mice by the introduction of floxed Smarca4 alleles. Unexpectedly, mutated and thereby stabilized β-catenin on its own induced severe developmental phenotypes in male and female Blbp-cre::Ctnnb1(ex3)fl/wt mice in our hands, including a thinned cerebral cortex, hydrocephalus, missing cerebellar layering, and cell accumulations in the brainstem and cerebellum. An additional loss of SMARCA4 even resulted in prenatal death for most mice. Respective Blbp-cre::Ctnnb1(ex3)fl/wt::Smarca4fl/rec mutants (male and female) developed large proliferative lesions in the cerebellum evolving from E13.5 to E16.5. Histological and molecular analysis of these lesions by DNA methylation profiling and single-cell RNA sequencing suggested an origin in early undifferentiated SOX2-positive cerebellar progenitors. Furthermore, upregulated WNT signaling, altered actin/cytoskeleton organization, and reduced neuronal differentiation were evident in mutant cells. In vitro, cells harboring alterations in both Ctnnb1 and Smarca4 were negatively selected and did not show tumorigenic potential after transplantation in adult female recipient mice. However, in cerebellar explant cultures, mutant cells displayed significantly increased proliferation, suggesting an important role of the embryonic microenvironment in the development of lesions. Altogether, these results represent an important first step toward the unraveling of tumorigenic mechanisms induced by aberrant WNT signaling and SMARCA4 deficiency.

Diagnostic Utility of GATA3 and ISL1 in Differentiating Neuroblastoma From Other Pediatric Malignant Small Round Blue Cell Tumors

Accurate diagnosis of neuroblastoma may be challenging, especially with limited or inadequate specimen and at the metastatic sites due to overlapping imaging, histopathologic, and immunohistochemical (immunohistochemistry [IHC]; infidelity among various lineage-associated transcription factors eg FLI1, transducin-like enhancer 1, etc) features. GATA3 and ISL1 have recently been described as markers of neuroblastic differentiation. This study aims at determining the diagnostic utility of GATA3 and ISL1 in differentiating neuroblastoma from other pediatric malignant small round blue cell tumors.

We evaluated GATA3 and ISL1 expression in 74 pediatric small round blue cell tumors that included 23 NMYC-amplified neuroblastomas, 11 EWSR1-rearranged round cell sarcomas, 7 SYT::SSX1-rearranged synovial sarcomas, 5 embryonal rhabdomyosarcomas, 10 Wilms tumors (nephroblastomas), 7 lymphoblastic lymphoma, 7 medulloblastoma, and 4 desmoplastic small round cell tumor.

All 23 neuroblastomas (moderate to strong staining in >50% of the tumor cells), 5 T-lymphoblastic lymphomas (moderate to strong staining in 40%-90% of the tumor cells), and 2 desmoplastic small round cell tumors (weak to moderate staining in 20%-30% of the tumor cells) expressed GATA3, while other tumors were negative. ISL1 immunoreactivity was observed in 22 (96%) neuroblastomas (strong staining in in >50% of the tumor cells, n  =  17; moderate to strong staining in 26%-50% of the tumor cells, n  =  5), 3 embryonal rhabdomyosarcoma (moderate to strong staining in 30%-85% of the tumor cells), 1 synovial sarcoma (weak staining in 20% of the tumor cells), and 7 medulloblastoma (strong staining in 60%-90% of the tumor cells). Other tumors were negative. Overall, GATA3 showed 86% specificity, 100% sensitivity, and 90% accuracy for neuroblastoma, with a positive predictive value (PPV) and negative predictive value (NPV) of 77% and 100%, respectively. ISLI showed 72% specificity, 96% sensitivity, and 81% accuracy for neuroblastoma, with a PPV and NPV of 67% and 97%, respectively. After the exclusion of T-lymphoblastic lymphoma and desmoplastic small round cell tumors, GATA3 had 100% specificity, sensitivity, accuracy, and PPV and NPV for neuroblastoma. Similarly, in pediatric small round blue cell tumors, ISL1 had 100% specificity, sensitivity, accuracy, PPV, and NPV for neuroblastoma, after embryonal rhabdomyosarcoma, synovial sarcoma, and medulloblastoma were excluded.

CONCLUSIONS

GATA3 and ISL1 may be valuable in the diagnostic work-up of neuroblastoma and may reliably be used to support the neuroblastic lineage of pediatric small round blue cell tumors. Furthermore, dual positivity helps in challenging scenarios, when there is equivocal imaging, overlapping IHC features, limited specimen, and the lack of facility for a molecular work up.

Revealing the Ferroptotic Phenotype of Medulloblastoma

The interaction of iron and oxygen is an integral part of the development of life on Earth. Nonetheless, this unique chemistry continues to fascinate and puzzle, leading to new biological ventures. In 2012, a Columbia University group recognized this interaction as a central event leading to a new type of regulated cell death named "ferroptosis." The major feature of ferroptosis is the accumulation of lipid hydroperoxides due to (1) dysfunctional antioxidant defense and/or (2) overwhelming oxidative stress, which most frequently coincides with increased content of free labile iron in the cell. This is normally prevented by the canonical anti-ferroptotic axis comprising the cystine transporter xCT, glutathione (GSH), and GSH peroxidase 4 (GPx4). Since ferroptosis is not a programmed type of cell death, it does not involve signaling pathways characteristic of apoptosis. The most common way to prove this type of cell death is by using lipophilic antioxidants (vitamin E, ferrostatin-1, etc.) to prevent it. These molecules can approach and detoxify oxidative damage in the plasma membrane. Another important aspect in revealing the ferroptotic phenotype is detecting the preceding accumulation of lipid hydroperoxides, for which the specific dye BODIPY C11 is used. The present manuscript will show how ferroptosis can be induced in wild-type medulloblastoma cells by using different inducers: erastin, RSL3, and iron-donor. Similarly, the xCT-KO cells that grow in the presence of NAC, and which undergo ferroptosis once NAC is removed, will be used. The characteristic "bubbling" phenotype is visible under the light microscope within 12-16 h from the moment of ferroptosis triggering. Furthermore, BODIPY C11 staining followed by FACS analysis to show the accumulation of lipid hydroperoxides and consequent cell death using the PI staining method will be used. To prove the ferroptotic nature of cell death, ferrostatin-1 will be used as a specific ferroptosis-preventing agent.

Palliative care for children with central nervous system tumors: results of a Spanish multicenter study

BACKGROUND

Brain tumors represent the most common cause of cancer-related death in children. Few studies concerning the palliative phase in children with brain tumors are available.

OBJECTIVES

(i) To describe the palliative phase in children with brain tumors; (ii) to determine whether the use of palliative sedation (PS) depends on the place of death, the age of the patient, or if they received specific palliative care (PC).

METHODS

Retrospective multicenter study between 2010 and 2021, including children from one month to 18 years, who had died of a brain tumor.

RESULTS

228 patients (59.2% male) from 10 Spanish institutions were included. Median age at diagnosis was 5 years (IQR 2-9) and median age at death was 7 years (IQR 4-11). The most frequent tumors were medulloblastoma (25.4%) and diffuse intrinsic pontine glioma (DIPG) (24.1%). Median number of antineoplastic regimens were 2 (range 0-5 regimens). During palliative phase, 52.2% of the patients were attended by PC teams, while 47.8% were cared exclusively by pediatric oncology teams. Most common concerns included motor deficit (93.4%) and asthenia (87.5%) and communication disorders (89.8%). Most frequently prescribed supportive drugs were antiemetics (83.6%), opioids (81.6%), and dexamethasone (78.5%). PS was administered to 48.7% patients. Most of them died in the hospital (85.6%), while patients who died at home required PS less frequently (14.4%) (p = .01).

CONCLUSION

Children dying from CNS tumors have specific needs during palliative phase. The optimal indication of PS depended on the center experience although, in our series, it was also influenced by the place of death.

Maternal Prenatal Use of Alcohol, Tobacco, and Illicit Drugs and Associations with Childhood Cancer Subtypes

BACKGROUND

The association between childhood cancer risk and maternal prenatal substance use/abuse remains uncertain due to modest sample sizes and heterogeneous study designs.

METHODS

We surveyed parents of children with cancer regarding maternal gestational use of tobacco, alcohol, and illicit drugs, using a Likert-type scale, and demographic, perinatal, and clinical variables. Multivariable log-Poisson regression assessed differences in frequency of prenatal substance use across fifteen childhood cancer subtypes, adjusting for birthweight, gestational age, and demographic factors.

RESULTS

Respondents from 3,145 unique families completed the survey (92% biological mothers). A minority reported gestational use of tobacco products (14%), illicit drugs including marijuana or cocaine (4%), or more than a moderate amount of alcohol (2%). Prenatal illicit drug use was associated with increased prevalence of intracranial embryonal tumors [prevalence ratio (PR) = 1.94; confidence interval [CI], 1.05-3.58], including medulloblastoma (PR = 1.82) and supratentorial primitive neuroectodermal tumors (PNET; PR = 2.66), and was also associated with retinoblastoma (PR = 3.11; CI, 1.20-8.08). Moderate to heavy alcohol consumption was strongly associated with elevated prevalence of non-Hodgkin lymphoma (PR = 5.94; CI, 1.84-19.21). Prenatal smoking was not associated with elevated prevalence of any childhood cancer subtype.

CONCLUSIONS

We identify novel associations between illicit drug use during pregnancy and increased prevalence of nonglioma central nervous system tumors, including medulloblastoma, supratentorial PNETs, and retinoblastoma. Gestational exposure to alcohol was positively associated with non-Hodgkin lymphoma.

IMPACT

Although alcohol and tobacco use during pregnancy has declined, gestational cannabis use has risen. Investigating its impact on neurodevelopment and brain tumorigenesis is vital, with important implications for childhood cancer research and public health education.

Adolescents and Young Adults With Cancer: CNS Tumors

Tumors of CNS are common in adolescents and young adults (AYAs). As the second leading cause of cancer-related death, CNS tumors in AYAs require improved clinical management. In this review, we discussed the current diagnostic approaches and recommended management strategies for malignant tumors in adult-type (IDH-mutant gliomas) and pediatric-type gliomas (pediatric high-grade gliomas), ependymoma and medulloblastoma, which commonly occur in AYAs. The impact of advanced molecular diagnostic approaches on the understanding of tumor biology of AYA CNS tumors is emphasized. To enhance participation in clinical trials, which poses a unique challenge in AYAs with CNS tumors, we propose encouraging referrals to neuro-oncology specialty care and improving collaboration between oncologists who care for both pediatric and adult patients. This will ensure better representation of AYA patients in research studies. Finally, we discussed the importance of considering neurocognitive and psychological function in AYAs with CNS tumor.

Brain Tumor Imaging in Adolescents and Young Adults: 2021 WHO Updates for Molecular-based Tumor Types

Published in 2021, the fifth edition of the World Health Organization (WHO) classification of tumors of the central nervous system (CNS) introduced new molecular criteria for tumor types that commonly occur in either pediatric or adult age groups. Adolescents and young adults (AYAs) are at the intersection of adult and pediatric care, and both pediatric-type and adult-type CNS tumors occur at that age. Mortality rates for AYAs with CNS tumors have increased by 0.6% per year for males and 1% per year for females from 2007 to 2016. To best serve patients, it is crucial that both pediatric and adult radiologists who interpret neuroimages are familiar with the various pediatric- and adult-type brain tumors and their typical imaging morphologic characteristics. Gliomas account for approximately 80% of all malignant CNS tumors in the AYA age group, with the most common types observed being diffuse astrocytic and glioneuronal tumors. Ependymomas and medulloblastomas also occur in the AYA population but are seen less frequently. Importantly, biologic behavior and progression of distinct molecular subgroups of brain tumors differ across ages. This review discusses newly added or revised gliomas in the fifth edition of the CNS WHO classification, as well as other CNS tumor types common in the AYA population.

mRNA-based precision targeting of neoantigens and tumor-associated antigens in malignant brain tumors

BACKGROUND

Despite advancements in the successful use of immunotherapy in treating a variety of solid tumors, applications in treating brain tumors have lagged considerably. This is due, at least in part, to the lack of well-characterized antigens expressed within brain tumors that can mediate tumor rejection; the low mutational burden of these tumors that limits the abundance of targetable neoantigens; and the immunologically "cold" tumor microenvironment that hampers the generation of sustained and productive immunologic responses. The field of mRNA-based therapeutics has experienced a boon following the universal approval of COVID-19 mRNA vaccines. mRNA-based immunotherapeutics have also garnered widespread interest for their potential to revolutionize cancer treatment. In this study, we developed a novel and scalable approach for the production of personalized mRNA-based therapeutics that target multiple tumor rejection antigens in a single therapy for the treatment of refractory brain tumors.

METHODS

Tumor-specific neoantigens and aberrantly overexpressed tumor-associated antigens were identified for glioblastoma and medulloblastoma tumors using our cancer immunogenomics pipeline called Open Reading Frame Antigen Network (O.R.A.N). Personalized tumor antigen-specific mRNA vaccine was developed for each individual tumor model using selective gene capture and enrichment strategy. The immunogenicity and efficacy of the personalized mRNA vaccines was evaluated in combination with anti-PD-1 immune checkpoint blockade therapy or adoptive cellular therapy with ex vivo expanded tumor antigen-specific lymphocytes in highly aggressive murine GBM models.

RESULTS

Our results demonstrate the effectiveness of the antigen-specific mRNA vaccines in eliciting robust anti-tumor immune responses in GBM hosts. Our findings substantiate an increase in tumor-infiltrating lymphocytes characterized by enhanced effector function, both intratumorally and systemically, after antigen-specific mRNA-directed immunotherapy, resulting in a favorable shift in the tumor microenvironment from immunologically cold to hot. Capacity to generate personalized mRNA vaccines targeting human GBM antigens was also demonstrated.

CONCLUSIONS

We have established a personalized and customizable mRNA-therapeutic approach that effectively targets a plurality of tumor antigens and demonstrated potent anti-tumor response in preclinical brain tumor models. This platform mRNA technology uniquely addresses the challenge of tumor heterogeneity and low antigen burden, two key deficiencies in targeting the classically immunotherapy-resistant CNS malignancies, and possibly other cold tumor types.

Pediatric-Like Brain Tumors in Adults

Pediatric brain tumors are different to those found in adults in pathological type, anatomical site, molecular signature, and probable tumor drivers. Although these tumors usually occur in childhood, they also rarely present in adult patients, either as a de novo diagnosis or as a delayed recurrence of a pediatric tumor in the setting of a patient that has transitioned into adult services.Due to the rarity of pediatric-like tumors in adults, the literature on these tumor types in adults is often limited to small case series, and treatment decisions are often based on the management plans taken from pediatric studies. However, the biology of these tumors is often different from the same tumors found in children. Likewise, adult patients are often unable to tolerate the side effects of the aggressive treatments used in children-for which there is little or no evidence of efficacy in adults. In this chapter, we review the literature and summarize the clinical, pathological, molecular profile, and response to treatment for the following pediatric tumor types-medulloblastoma, ependymoma, craniopharyngioma, pilocytic astrocytoma, subependymal giant cell astrocytoma, germ cell tumors, choroid plexus tumors, midline glioma, and pleomorphic xanthoastrocytoma-with emphasis on the differences to the adult population.

Parent ratings of executive functioning in pediatric survivors of medulloblastoma and pilocytic astrocytoma

The present study compared parent-rated executive functioning in pediatric medulloblastoma (MB) and pilocytic astrocytoma (PA) survivors. Although standard care for both includes surgical resection, children with MB additionally receive chemotherapy and craniospinal irradiation. Given well-documented neurocognitive late effects associated with the latter, we anticipated poor parent-reported executive functioning in MB survivors. Parents/guardians of 36 MB survivors and 20 PA survivors completed the Behavior Rating Inventory of Executive Functioning (BRIEF). PA survivors were younger at diagnosis (t[51.97] = 3.07, p < .001, d = 0.86) and demonstrated higher IQ (t[54] = -3.51, p < .001, d = 0.95). However, relative to the MB group, the PA group was rated as having significantly more problems on all BRIEF scales (all p ≤ .05; d = 0.30 - 1.10), except the Shift scale. Additionally, all mean BRIEF scores for MB survivors were within normal limits, whereas for PA survivors, all mean BRIEF scores except for Organization of Materials were significantly discrepant from normative means. Overall, PA survivors were rated as demonstrating poorer executive function than MB survivors. Five theories are discussed as possible explanations for these surprising findings: two related to group differences, two related to potential sources of parental bias, and one related to the nature of questionnaire-based assessment. All these theories represent directions for future research. Parent questionnaires such as the BRIEF may have real-world implications for pediatric brain tumor survivors. Future research should explore factors affecting parent ratings of executive functioning in these populations, along with comparison to performance-based measures.

Current practice of cancer predisposition testing in pediatric patients with CNS tumors in the United States

An estimated 8.6% of all pediatric patients with central nervous system tumors (CNSTs) have underlying hereditary cancer predisposition (HCP). Identifying HCP affects risk assessment and medical management options for the patients and their family members. However, there is a lack of consensus on the optimal germline genetic testing (GT) approach for pediatric patients with CNSTs. As a first step in addressing the need for consensus, we surveyed oncology and genetics providers from 47 institutions in professional organizations across the United States. We investigated their current practice (e.g., GT decisions and ordering practices) when assessing pediatric patients with CNSTs for HCP. We received 60 responses from 21 pediatric oncologists, 10 neuro-oncologists, 28 genetics providers, and one neuro-oncologist/geneticist. Results demonstrate genetic counselors, followed by oncologists, most often facilitated consent, ordered testing, and selected which test to order. The most ordered test was a multi-gene panel (60%). Of 18 CNST diagnoses, choroid plexus carcinoma (CPC) was the diagnosis for which most providers (78%) reported they would offer GT. For medulloblastoma, 56% overall reported they would offer GT (64% of genetics providers, 62% of neuro-oncologists, 20% of pediatric oncologists; p = .050). Findings suggest that even for the CNSTs most commonly known to be associated with HCP regardless of family history, there was variability in providers' decisions to offer GT. The lack of consensus in GT decisions in our study indicates inconsistencies in the genetics care of pediatric patients with CNSTs, demonstrating a need for consensus guidelines to promote consistent genetics care.

Protocol for mapping the metabolome and lipidome of medulloblastoma cells using liquid chromatography-mass spectrometry

Liquid chromatography-mass spectrometry (LC-MS)-based metabolomics and lipidomics have recently been used to show that MYC-amplified group 3 medulloblastoma tumors are driven by metabolic reprogramming. Here, we present a protocol to extract metabolites and lipids from human medulloblastoma brain tumor-initiating cells and normal neural stem cells. We describe untargeted LC-MS methods that can be used to achieve extensive coverage of the polar metabolome and lipidome. Finally, we detail strategies for metabolite identification and data analysis. For complete details on the use and execution of this protocol, please refer to Gwynne et al.1.

MR dynamic-susceptibility-contrast perfusion metrics in the presurgical discrimination of adult solitary intra-axial cerebellar tumors

OBJECTIVES

Adult solitary intra-axial cerebellar tumors are uncommon. Their presurgical differentiation based on neuroimaging is crucial, since management differs substantially. Comprehensive full assessment of MR dynamic-susceptibility-contrast perfusion-weighted imaging (DSC-PWI) may reveal key differences between entities. This study aims to provide new insights on perfusion patterns of these tumors and to explore the potential of DSC-PWI in their presurgical discrimination.

METHODS

Adult patients with a solitary cerebellar tumor on presurgical MR and confirmed histological diagnosis of metastasis, medulloblastoma, hemangioblastoma, or pilocytic astrocytoma were retrospectively retrieved (2008-2023). Volumetric segmentation of tumors and normal-appearing white matter (for normalization) was semi-automatically performed on CE-T1WI and coregistered with DSC-PWI. Mean normalized values per patient tumor-mask of relative cerebral blood volume (rCBV), percentage of signal recovery (PSR), peak height (PH), and normalized time-intensity curves (nTIC) were extracted. Statistical comparisons were done. Then, the dataset was split into training (75%) and test (25%) cohorts and a classifier was created considering nTIC, rCBV, PSR, and PH in the model.

RESULTS

Sixty-eight patients (31 metastases, 13 medulloblastomas, 13 hemangioblastomas, and 11 pilocytic astrocytomas) were included. Relevant differences between tumor types' nTICs were demonstrated. Hemangioblastoma showed the highest rCBV and PH, pilocytic astrocytoma the highest PSR. All parameters showed significant differences on the Kruskal-Wallis tests (p < 0.001). The classifier yielded an accuracy of 98% (47/48) in the training and 85% (17/20) in the test sets.

CONCLUSIONS

Intra-axial cerebellar tumors in adults have singular and significantly different DSC-PWI signatures. The combination of perfusion metrics through data-analysis rendered excellent accuracies in discriminating these entities.

CLINICAL RELEVANCE STATEMENT

In this study, the authors constructed a classifier for the non-invasive imaging presurgical diagnosis of adult intra-axial cerebellar tumors. The resultant tool can be a support for decision-making in the clinical practice and enables optimal personalized patient management.

KEY POINTS

• Adult intra-axial cerebellar tumors exhibit specific, singular, and statistically significant different MR dynamic-susceptibility-contrast perfusion-weighted imaging (DSC-PWI) signatures. • Data-analysis, applied to MR DSC-PWI, could provide added value in the presurgical diagnosis of solitary cerebellar metastasis, medulloblastoma, hemangioblastoma, and pilocytic astrocytoma. • A classifier based on DSC-PWI metrics yields excellent accuracy rates and could be used as a support tool for radiologic diagnosis with clinician-friendly displays.

Engineering subarachnoid trabeculae with electrospun poly(caprolactone) (PCL) scaffolds to study leptomeningeal metastasis in medulloblastoma

Leptomeningeal metastasis (LM) occurs when cancer cells infiltrate the subarachnoid space (SAS) and metastasize to the fibrous structures that surround the brain and spinal cord. These structures include the leptomeninges (i.e., the pia mater and arachnoid mater), as well as subarachnoid trabeculae, which are collagen-rich fibers that provide mechanical structure for the SAS, support resident cells, and mediate flow of cerebrospinal fluid (CSF). Although there is a strong expectation that the presence of fibers within the SAS influences LM to be a major driver of tumor progression and lethality, exactly how trabecular architecture relates to the process of metastasis in cancer is poorly understood. This lack of understanding is likely due in part to the difficulty of accessing and manipulating this tissue compartment in vivo. Here, we utilized electrospun polycaprolactone (PCL) to produce structures bearing remarkable morphological similarity to native SAS fiber architecture. First, we profiled the native architecture of leptomeningeal and trabecular fibers collected from rhesus macaque monkeys, evaluating both qualitative and quantitative differences in fiber ultrastructure for various regions of the CNS. We then varied electrospinning parameters to produce a small library of PCL scaffolds possessing distinct architectures mimicking the range of fiber properties observed in vivo. For proof of concept, we studied the metastasis-related behaviors of human pediatric medulloblastoma cells cultured in different fiber microenvironments. These studies demonstrated that a more open, porous fiber structure facilitates DAOY cell spread across and infiltration into the meningeal mimic. Our results present a new tissue engineered model of the subarachnoid space and affirm the expectation that fiber architecture plays an important role in mediating metastasis-related behaviors in an in vitro model of pediatric medulloblastoma.

The unique immune ecosystems in pediatric brain tumors: integrating single-cell and bulk RNA-sequencing

Background

The significant progress of immune therapy in non-central nervous system tumors has sparked interest in employing the same strategy for adult brain tumors. However, the advancement of immunotherapy in pediatric central nervous system (CNS) tumors is not yet on par. Currently, there is a lack of comprehensive comparative studies investigating the immune ecosystem in pediatric and adult CNS tumors at a high-resolution single-cell level.

Methods

In this study, we comprehensively analyzed over 0.3 million cells from 171 samples, encompassing adult gliomas (IDH wild type and IDH mutation) as well as four major types of pediatric brain tumors (medulloblastoma (MB), ependymoma (EPN), H3K27M-mutation (DIPG), and pediatric IDH-mutation glioma (P-IDH-M)). Our approach involved integrating publicly available and newly generated single-cell datasets. We compared the immune landscapes in different brain tumors, as well as the detailed functional phenotypes of T-cell and myeloid subpopulations. Through single-cell analysis, we identified gene sets associated with major cell types in the tumor microenvironment (gene features from single-cell data, scFes) and compared them with existing gene sets such as GSEA and xCell. The CBTTC and external GEO cohort was used to analyze and validate the immune-stromal-tumor patterns in pediatric brain tumors which might potentially respond to the immunotherapy.

Results

From the perspective of single-cell analysis, it was observed that major pediatric brain tumors (MB, EPN, P-IDH-M, DIPG) exhibited lower immune contents compared with adult gliomas. Additionally, these pediatric brain tumors displayed diverse immunophenotypes, particularly in regard to myeloid cells. Notably, the presence of HLA-enriched myeloid cells in MB was found to be independently associated with prognosis. Moreover, the scFes, when compared with commonly used gene features, demonstrated superior performance in independent single-cell datasets across various tumor types. Furthermore, our study revealed the existence of heterogeneous immune ecosystems at the bulk-RNA sequencing level among different brain tumor types. In addition, we identified several immune-stromal-tumor patterns that could potentially exhibit significant responses to conventional immune checkpoint inhibitors.

Conclusion

The single-cell technique provides a rational path to deeply understand the unique immune ecosystem of pediatric brain tumors. In spite of the traditional attitudes of "cold" tumor towards pediatric brain tumor, the immune-stroma-tumor patterns identified in this study suggest the feasibility of immune checkpoint inhibitors and pave the way for the upcoming tide of immunotherapy in pediatric brain tumors.

Pediatric phase 2 trial of a WEE1 inhibitor, adavosertib (AZD1775), and irinotecan for relapsed neuroblastoma, medulloblastoma, and rhabdomyosarcoma

BACKGROUND

Inhibition of the WEE1 kinase by adavosertib (AZD1775) potentiates replicative stress from genomic instability or chemotherapy. This study reports the pediatric solid tumor phase 2 results of the ADVL1312 trial combining irinotecan and adavosertib.

METHODS

Pediatric patients with recurrent neuroblastoma (part B), medulloblastoma/central nervous system embryonal tumors (part C), or rhabdomyosarcoma (part D) were treated with irinotecan and adavosertib orally for 5 days every 21 days. The combination was considered effective if there were at least three of 20 responses in parts B and D or six of 19 responses in part C. Tumor tissue was analyzed for alternative lengthening of telomeres and ATRX. Patient's prior tumor genomic analyses were provided.

RESULTS

The 20 patients with neuroblastoma (part B) had a median of three prior regimens and 95% had a history of prior irinotecan. There were three objective responses (9, 11, and 18 cycles) meeting the protocol defined efficacy end point. Two of the three patients with objective responses had tumors with alternative lengthening of telomeres. One patient with pineoblastoma had a partial response (11 cycles), but parts C and D did not meet the protocol defined efficacy end point. The combination was well tolerated and there were no dose limiting toxicities at cycle 1 or beyond in any parts of ADVL1312 at the recommended phase 2 dose.

CONCLUSION

This is first phase 2 clinical trial of adavosertib in pediatrics and the first with irinotecan. The combination may be of sufficient activity to consider further study of adavosertib in neuroblastoma.

Re-irradiation for recurrent/progressive pediatric brain tumors: from radiobiology to clinical outcomes

INTRODUCTION

Brain tumors are the most common solid tumors in children. Neurosurgical excision, radiotherapy, and/or chemotherapy represent the standard of care in most histopathological types of pediatric central nervous system (CNS) tumors. Even though the successful cure rate is reasonable, some patients may develop recurrence locally or within the neuroaxis.

AREA COVERED

The management of these recurrences is not easy; however, significant advances in neurosurgery, radiation techniques, radiobiology, and the introduction of newer biological therapies, have improved the results of their salvage treatment. In many cases, salvage re-irradiation is feasible and has achieved encouraging results. The results of re-irradiation depend upon several factors. These factors include tumor type, extent of the second surgery, tumor volume, location of the recurrence, time that elapses between the initial treatment, the combination with other treatment agents, relapse, and the initial response to radiotherapy.

EXPERT OPINION

Reviewing the radiobiological basis and clinical outcome of pediatric brain re-irradiation revealed that re-irradiation is safe, feasible, and indicated for recurrent/progressive different tumor types such as; ependymoma, medulloblastoma, diffuse intrinsic pontine glioma (DIPG) and glioblastoma. It is now considered part of the treatment armamentarium for these patients. The challenges and clinical results in treating recurrent pediatric brain tumors were highly documented.

Mid-cavitary hypertrophy after myocarditis in a patient with operated medulloblastoma

A 16-month-old girl was referred for tachycardia and upper respiratory tract infection. Echocardiographic examination revealed pericardial effusion, mild mitral regurgitation, and left ventricle systolic dysfunction. Patient was positive for Parainfluenza type 4 virus. Her laboratory tests revealed increased troponin I level. The patient was treated with intravenous immunoglobulin considering acute viral myopericarditis. Two weeks after treatment, midventricular hypertrophy was detected.

The Burden of Surviving Childhood Medulloblastoma: A Population-Based, Matched Cohort Study in Ontario, Canada

PURPOSE

Survivors of childhood medulloblastoma suffer from substantial late effects. We characterized these sequelae using real-world health services data in a population-based cohort of medulloblastoma survivors.

METHODS

All 5-year medulloblastoma survivors diagnosed age < 18 years between 1987 and 2015 in Ontario, Canada, were identified and matched 1:5 with population controls. Index date was 5 years from latest pediatric cancer event. Linkage to provincial administrative health data allowed for comparison of cumulative incidences of several adverse outcomes.

RESULTS

Two hundred thirty survivors, 81.3% of whom had received craniospinal irradiation, were matched with 1,150 controls. The 10-year postindex cumulative incidence of all-cause mortality was 7.9% (95% CI, 3.9 to 11.8) in survivors versus 0.6% (95% CI, 0.1 to 1.1) in controls (hazard ratio [HR], 21.5; 95% CI, 9.8 to 54.0). The cumulative incidence of stroke was higher in survivors (4.8%; 95% CI, 2.2 to 9.0) compared with controls (0.1; 95% CI, 0.01 to 0.7; HR, 45.6; 95% CI, 12.8 to 289.8). Hearing loss requiring an amplification device was present in 24.9% (95% CI, 18.8 to 31.4) of survivors versus 0.3% (95% CI, 0.1 to 1.0) of controls (HR, 96.3; 95% CI, 39.7 to 317.3). Disability support prescription claims were submitted by 44.5% (95% CI, 37.1 to 51.6) of survivors versus 5.5% (95% CI, 4.2 to 7.1) of controls (HR, 10.0; 95% CI, 7.3 to 13.6). Female survivors were significantly less likely to deliver a liveborn child compared with controls (HR, 0.2; 95% CI, 0.1 to 0.7).

CONCLUSION

Survivors of medulloblastoma have significant long-term medical sequelae, increased all-cause mortality, and are frequently dependent on disability supports. Efforts to reduce the toxicity of current therapy, specifically incorporating molecularly informed risk stratification to spare low- and intermediate-risk survivors the toxicity of treatment, are urgently needed. These findings should prompt a re-evaluation of our current treatment approaches where research focused on late-effect interventions should be prioritized.

ARF suppression by MYC but not MYCN confers increased malignancy of aggressive pediatric brain tumors

Medulloblastoma, the most common malignant pediatric brain tumor, often harbors MYC amplifications. Compared to high-grade gliomas, MYC-amplified medulloblastomas often show increased photoreceptor activity and arise in the presence of a functional ARF/p53 suppressor pathway. Here, we generate an immunocompetent transgenic mouse model with regulatable MYC that develop clonal tumors that molecularly resemble photoreceptor-positive Group 3 medulloblastoma. Compared to MYCN-expressing brain tumors driven from the same promoter, pronounced ARF silencing is present in our MYC-expressing model and in human medulloblastoma. While partial Arf suppression causes increased malignancy in MYCN-expressing tumors, complete Arf depletion promotes photoreceptor-negative high-grade glioma formation. Computational models and clinical data further identify drugs targeting MYC-driven tumors with a suppressed but functional ARF pathway. We show that the HSP90 inhibitor, Onalespib, significantly targets MYC-driven but not MYCN-driven tumors in an ARF-dependent manner. The treatment increases cell death in synergy with cisplatin and demonstrates potential for targeting MYC-driven medulloblastoma.

P-selectin-targeted nanocarriers induce active crossing of the blood-brain barrier via caveolin-1-dependent transcytosis

Medulloblastoma is the most common malignant paediatric brain tumour, with ~30% mediated by Sonic hedgehog signalling. Vismodegib-mediated inhibition of the Sonic hedgehog effector Smoothened inhibits tumour growth but causes growth plate fusion at effective doses. Here, we report a nanotherapeutic approach targeting endothelial tumour vasculature to enhance blood-brain barrier crossing. We use fucoidan-based nanocarriers targeting endothelial P-selectin to induce caveolin-1-dependent transcytosis and thus nanocarrier transport into the brain tumour microenvironment in a selective and active manner, the efficiency of which is increased by radiation treatment. In a Sonic hedgehog medulloblastoma animal model, fucoidan-based nanoparticles encapsulating vismodegib exhibit a striking efficacy and marked reduced bone toxicity and drug exposure to healthy brain tissue. Overall, these findings demonstrate a potent strategy for targeted intracranial pharmacodelivery that overcomes the restrictive blood-brain barrier to achieve enhanced tumour-selective penetration and has therapeutic implications for diseases within the central nervous system.

Targeting BRD4 and PI3K signaling pathways for the treatment of medulloblastoma

Medulloblastoma (MB) is a malignant pediatric brain tumor which shows upregulation of MYC and sonic hedgehog (SHH) signaling. SHH inhibitors face acquired resistance, which is a major cause of relapse. Further, direct MYC oncogene inhibition is challenging, inhibition of MYC upstream insulin-like growth factor/ phosphatidylinositol-4,5-bisphosphate 3-kinase (IGF/PI3K) is a promising alternative. While PI3K inhibition activates resistance mechanisms, simultaneous inhibition of bromodomain-containing protein 4 (BRD4) and PI3K can overcome resistance. We synthesized a new molecule 8-(2,3-dihydrobenzo[b] [1, 4] dioxin-6-yl)-2-morpholino-4H-chromen-4-one (MDP5) that targets both BRD4 and PI3K pathways. We used X-ray crystal structures and a molecular modeling approach to confirm the interactions between MDP5 with bromo domains (BDs) from both BRD2 and BRD4, and molecular modeling for PI3K binding. MDP5 was shown to inhibit target pathways and MB cell growth in vitro and in vivo. MDP5 showed higher potency in DAOY cells (IC50 5.5 μM) compared to SF2523 (IC50 12.6 μM), and its IC50 values in HD-MB03 cells were like SF2523. Treatment of MB cells with MDP5 significantly decreased colony formation, increased apoptosis, and halted cell cycle progression. Further, MDP5 was well tolerated in NSG mice bearing either xenograft or orthotopic MB tumors at the dose of 20 mg/kg, and significantly reduced tumor growth and prolonged animal survival.

Brain and Spinal Cord Tumors of Embryonic Origin

Embryonal tumors (ETs) of the central nervous system (CNS) comprise a large heterogeneous group of highly malignant tumors that predominantly affect children and adolescents. Currently, the neoplasms classified as ET are the medulloblastoma (MB), embryonal tumors with multilayered rosettes (ETMR), medulloepithelioma (ME), CNS neuroblastoma (NB), CNS ganglioneuroblastoma (GNB), atypical teratoid/rhabdoid tumors (AT/RT), and CNS embryonal tumors with rhabdoid features. All these tumors are classified as malignant-grade IV neoplasms, and the prognosis of patients with these neoplasms is very poor. Currently, except for the histological classification of MB, the recently utilized WHO classification accepts a novel molecular classification of MBs into four distinct molecular subgroups: wingless/integrated (WNT)-activated, sonic hedgehog (Shh), and the numerical Group3 and Group 4. The combination of both histological and genetic classifications has substantial prognostic significance, and patients are categorized as low risk with over 90% survival, the standard risk with 75-90% survival, high risk with 50-75% survival, and very high risk with survival rate lower than 50%. Children under three years are predominantly affected by AT/RT and represent about 20% of all CNS tumors in this age group. AT/RT is typically located in the posterior fossa (mainly in cerebellopontine angle) in 50-60% of the cases. The pathogenesis of this neoplasm is strongly associated with loss of function of the SMARCB1 (INI1, hSNF5) gene located at the 22q11.23 chromosome, or very rarely with alterations in (SMARCA4) BRG1 gene. The cells of this neoplasm resemble those of other neuronal tumors, and hence, immunochemistry markers have been utilized, such as smooth muscle actin, epithelial membrane antigen, vimentin, and lately antibodies for INI1. ETMRs are characterized by the presence of ependymoblastic rosettes formed by undifferentiated neuroepithelial cells and neuropil. The tumorigenesis of ETMRs is strongly related to the amplification of the pluripotency factor Chr19q13.41 miRNA cluster (C19MC) present in around 90% of the cases. Additionally, the expression of LIN28A is a highly sensitive and specific marker of ETMR diagnosis, as it is overexpressed in almost all cases of ETMR and is related to poor patient outcomes. The treatment of patients with ETs includes a combination of surgical resection, radiotherapy (focal or craniospinal), and chemotherapeutic agents. Currently, there is a trend to reduce the dose of craniospinal irradiation in the treatment of low-risk MBs. Novel targeted therapies are expected in the treatment of patients with MBs due to the identification of the main driver genes. Survival rates vary between ET types and their subtypes, with ganglioneuroblastoma having over 95% 5-year survival rate, while ATRT is probably linked with the worst prognosis with a 30% 5-year survival rate.

Could dietary erucic acid lower risk of brain tumors? An epidemiological look to Chinese population with implications for prevention and treatment

Erucic acid, an omega-9 monounsaturated fatty acid present in Brassicaceae plants (rapeseed and mustard oils) is highly consumed by the Chinese population and according to several global survey studies, its highest levels are encountered in the Chinese women's milk. Erucic acid is an activating ligand of the transcription factor PPARδ and an inhibitor of the transcriptional activity of PPARγ, which drive tumorigenesis of glioblastomas and medulloblastomas. In this theoretical review, we propose that erucic acid in diet may associate with the risk of brain tumors. High grade brain tumors including medulloblastomas in children and glioblastomas in adults have devastating consequences for human health and the latter tumors are practically incurable. CONCORD-3 epidemiological study recently published in 2021 revealed a low ratio of medulloblastomas in the pediatric age group and also a low ratio of glioblastomas in adults in the Chinese population. It is certain that such profound differences can not be attributed to a single genetic factor or a single nurture pattern. It is very likely that multiple hereditary, nutritional and environmental factors are responsible for these lower ratios; yet here we propose that erucic acid may be one of the contributing factors. If future epidemiological studies and animal models show antitumor activity of erucic acid regarding brain neoplasias, it can be utilized as a preventive strategy for populations possessing very high risks to develop brain tumors such as those harbouring hereditary syndromes increasing the vulnerability to develop such malignancies.

Development of GPC2-directed chimeric antigen receptors using mRNA for pediatric brain tumors

BACKGROUND

Pediatric brain tumors are the leading cause of cancer death in children with an urgent need for innovative therapies. Glypican 2 (GPC2) is a cell surface oncoprotein expressed in neuroblastoma for which targeted immunotherapies have been developed. This work aimed to characterize GPC2 expression in pediatric brain tumors and develop an mRNA CAR T cell approach against this target.

METHODS

We investigated GPC2 expression across a cohort of primary pediatric brain tumor samples and cell lines using RNA sequencing, immunohistochemistry, and flow cytometry. To target GPC2 in the brain with adoptive cellular therapies and mitigate potential inflammatory neurotoxicity, we used optimized mRNA to create transient chimeric antigen receptor (CAR) T cells. We developed four mRNA CAR T cell constructs using the highly GPC2-specific fully human D3 single chain variable fragment for preclinical testing.

RESULTS

We identified high GPC2 expression across multiple pediatric brain tumor types including medulloblastomas, embryonal tumors with multilayered rosettes, other central nervous system embryonal tumors, as well as definable subsets of highly malignant gliomas. We next validated and prioritized CAR configurations using in vitro cytotoxicity assays with GPC2-expressing neuroblastoma cells, where the light-to-heavy single chain variable fragment configurations proved to be superior. We expanded the testing of the two most potent GPC2-directed CAR constructs to GPC2-expressing medulloblastoma and high-grade glioma cell lines, showing significant GPC2-specific cell death in multiple models. Finally, biweekly locoregional delivery of 2-4 million GPC2-directed mRNA CAR T cells induced significant tumor regression in an orthotopic medulloblastoma model and significantly prolonged survival in an aggressive orthotopic thalamic diffuse midline glioma xenograft model. No GPC2-directed CAR T cell related neurologic or systemic toxicity was observed.

CONCLUSION

Taken together, these data show that GPC2 is a highly differentially expressed cell surface protein on multiple malignant pediatric brain tumors that can be targeted safely with local delivery of mRNA CAR T cells, laying the framework for the clinical translation of GPC2-directed immunotherapies for pediatric brain tumors.

An international study evaluating the epidemiology of intracranial germ cell tumors in the native versus immigrant Japanese populations: the need for an international registry

BACKGROUND

Pediatric intra-cranial germ cell tumors (iGCTs) occur at an incidence of 0.6-1.2 cases/million/year in Western countries. The incidence is reported up to 5 times higher in Japan. It is unknown whether this increased incidence is due to genetic predisposition or environment.

METHODS

The incidence of iGCTs in children ages 0-19 years was evaluated from December 1st, 1996-December 1st, 2016 in stable Japanese immigrant populations living abroad and compared to current native Japanese registry data. The incidence of medullobblastoma was used as a control to account for assumptions in the data. Sites were identified based on historical and population data of known large scale emigration from Japan during a period of industrialization from 1868-1912 which resulted in large, stable Japanese immigrant populations abroad. These three representative sites included Lima, Peru, San Paolo, Brazil, and Vancouver, Canada. Data was collected from registry and hospital-based resources within each region.

RESULTS

A review of the Brain Tumor Registry of Japan from 1984-2004 revealed an incidence of 2.5 cases/million/year, lower than previously reported, and a lower incidence of medulloblastoma at 1.2 cases/million/year. Data from Vancouver, Canada, Lima, Peru, and San Paolo, Brazil included a total population of 731,174 Japanese persons. The ratio of all medulloblastoma to iGCT cases in Japan was identified as 1:2 while the ratio was 2:1, 6.5:1, and 5:1, respectively, in the other three locations. The data suggests increased incidence in native Japan may not translate to higher incidence in immigrant Japanese populations abroad and a clear genetic component was not found in our data set.

CONCLUSIONS

A more precise and comprehensive study is needed to determine the cause of this difference in incidence. This study also emphasizes the importance of national and state registries and is a call to collaborate on state and country level epidemiology studies.

Pediatric medulloblastoma express immune checkpoint B7-H3

PURPOSE

Medulloblastomas (MB) are highly malignant brain tumors that predominantly occur in young infants. Immunotherapy to boost the immune system is emerging as a novel promising approach, but is often hampered by inhibitory immune checkpoints. In the present study, we have studied immune checkpoint B7-H3 expression in a tissue cohort of human pediatric MB.

METHODS

Expression of B7-H3 was detected by immunohistochemistry and classified via B7-H3 staining intensity and percentage of B7-H3 positive tumor cells. Subsequently, B7-H3 protein expression was distinguished in MB molecular subtypes and correlated to immune cell infiltrates, patient characteristics, and survival.

RESULTS

B7-H3 protein expression was found in 23 out of 24 (96%) human pediatric MB cases and in 17 out of 24 (71%) MB cases > 25% of tumor cells had any level of B7-H3 expression. B7-H3 protein expression was more frequent on Group-4 MB as compared with other molecular subtypes (p = 0.02). Tumors with high B7-H3 expression showed less influx of γδT cells (p = 0.002) and CD3+ T cells (p = 0.041).

CONCLUSION

Immune checkpoint B7-H3 is differentially expressed by the large majority of pediatric MB. This further warrants the development of novel B7-H3-directed (immuno)therapeutic methods for children with incurable, metastatic, or chemo-resistant MB.

A Case of Gorlin-Goltz Syndrome Without the Characteristic Physical Features That Was Diagnosed After the Development of a Fifth Cancer

We present a case of Gorlin-Goltz syndrome (GGS) in a patient who developed medulloblastoma, osteosarcoma, myelodysplastic syndrome, basal cell carcinoma, and odontogenic keratocyst by the age of 19 years. He had no known family history and no characteristic physical features of GGS. A frameshift mutation in the PTCH1 gene was found in the oral mucosa as a low-frequency mosaicism, basal cell carcinoma, and normal skin by whole exome sequencing of cancer susceptibility genes. Setting a therapeutic strategy with regard to second cancer development is important for pediatric cancer patients who have a background of cancer predisposition. Advances in comprehensive multigenetic analysis are anticipated to aid in developing such a strategy.

A SHHecret target of relapsed medulloblastoma: Astrocytes

In this issue of JEM, Guo et al. (2021. J. Exp. Med.https://doi.org/10.1084/jem.20202350) examine the importance of tumor-derived astrocytes in SHH-medulloblastoma recurrence. They show that tumor cells transdifferentiate to tumor-derived astrocytes via bone morphogenetic proteins and Sox9, which excitingly can be targeted by BMP inhibitors.

Granule Neuron Precursor-Derived Astrocytes Promote Medulloblastoma

Granule neuron precursors transdifferentiate into astrocytes in the tumor microenvironment.

[Subgroup-specific genomic alterations and potential prognostic biomarkers in childhood medulloblastomas]

Despite continuing advances in therapeutic strategies, survival of childhood medulloblastoma (MB) patients has reached a plateau in the past decade. Current clinical approaches divide patients into average- and high-risk treatment categories, although this categorization does not take patient heterogeneity into account. Advanced genomics has initiated an exciting transition that lead to a consensus of four distinct molecular entities within MBs (WNT-activated, SHH-activated, Group 3 MB, and Group 4 MB), each with distinct origins, demographics, molecular alterations and clinical outcomes. Within each of the four primary subgroups additional subtypes started to emerge with distinct biological backgrounds and clinical outcomes. Here we summarize subgroup-specific genomic alterations, affected signaling pathways and potential prognostic biomarkers. The poor prognosis associated with recurrent disease is responsible for the stagnant survival rates. Nevertheless, the mortality is unlikely to change without new biomarkers linked to different mechanisms of pathway activation.

[Risk factors for recurrence within 2 years in children with medulloblastoma]

OBJECTIVE

To investigate the risk factors for recurrence of medulloblastoma (MB) within 2 years and their influence on progression-free survival (PFS).

METHODS

A retrospective analysis was performed for the clinical data of 123 children with MB who were admitted from January to December, 2017. According to the presence or absence of recurrence, they were divided into recurrence group with 30 children and non-recurrence group with 93 children. The risk factors for recurrence within 2 years were analyzed, and PFS was compared between the children with different risk factors.

RESULTS

Large-cell/anaplastic type and M stage were risk factors for MB recurrence within 2 years. The risk of recurrence in the children with M+ MB was 3.525 times that in those with M0 MB, and the risk of recurrence in the children with large-cell/anaplastic MB was 3.358 times that in those with classic MB (P<0.05). The survival analysis showed that the median PFS time was 20 months in the children with M+ MB, and the 20-month PFS rate was 50% ± 11% in the children with M+ MB and 81% ± 5% in those with M0 MB (P<0.05). The 20-month PFS rate was 80% ± 5% in the children with classic MB, 65% ± 10% in those with desmoplastic/nodular MB, 86% ± 13% in those with MB with extensible nodularity, and 36% ± 20% in those with large-cell/anaplastic MB (P<0.05).

CONCLUSIONS

Recurrence is an important influencing factor for the prognosis of MB, and M+ stage and large-cell/anaplastic MB are risk factors for recurrence. Children with such risk factors tend to have a low PFS rate.

Multiomic Medulloblastomas

Epigenomics and transcriptomics of medulloblastoma-an important childhood brain tumor-segregate the disease into four clinically relevant subtypes. In this issue of Cancer Cell, Archer et al. and Forget et al. add the proteome to our multiomic map of this disease, revealing posttranscriptional and posttranslational variations with potential therapeutic implications.

Infrared Spectrophotometry Studies on Cerebral Tumor s-RNAs

Deuterated s-RNAs prepared from a medulloblastoma, a glioblastoma and a frontal lobe show a different relative intensity in the 1680 cm–1 band. The phenomenon can be related to the frequency in the base pairings; it may depend either on a proportionally different content of t-RNAs and/or on qualitative variations in the primary and secondary structure of the polynucleotides. Irrespective of the kind of variation and its causes, the finding once more proves the existence of chemical differences between neuroectodermal tumors, with an undifferentiated and those with an atypical cellular component.

Medulloblastoma Circulating Tumor Cells Form Leptomeningeal Metastases

NCAM⁺CD45⁺ medulloblastoma cells were shown to be medulloblastoma circulating tumor cells (CTC).

Targeting HDAC And PI3K Inhibits MYC-Driven Medulloblastoma Growth

HDAC inhibitors synergize with PI3K inhibitors to reduce MYC-driven medulloblastoma (MB) growth.

Exogenous HGF Bypasses the Effects of ErbB Inhibition on Tumor Cell Viability in Medulloblastoma Cell Lines

Recent clinical trials investigating receptor tyrosine kinase (RTK) inhibitors showed a limited clinical response in medulloblastoma. The present study investigated the role of micro-environmental growth factors expressed in the brain, such as HGF and EGF, in relation to the effects of hepatocyte growth factor receptor (MET) and epidermal growth factor receptor family (ErbB1-4) inhibition in medulloblastoma cell lines. Medulloblastoma cell lines were treated with tyrosine kinase inhibitors crizotinib or canertinib, targeting MET and ErbB1-4, respectively. Upon treatment, cells were stimulated with VEGF-A, PDGF-AB, HGF, FGF-2 or EGF. Subsequently, we measured cell viability and expression levels of growth factors and downstream signaling proteins. Addition of HGF or EGF phosphorylated MET or EGFR, respectively, and demonstrated phosphorylation of Akt and ERK1/2 as well as increased tumor cell viability. Crizotinib and canertinib both inhibited cell viability and phosphorylation of Akt and ERK1/2. Specifically targeting MET using shRNA’s resulted in decreased cell viability. Interestingly, addition of HGF to canertinib significantly enhanced cell viability as well as phosphorylation of Akt and ERK1/2. The HGF-induced bypass of canertinib was reversed by addition of crizotinib. HGF protein was hardly released by medulloblastoma cells itself. Addition of canertinib did not affect RTK cell surface or growth factor expression levels. This manuscript points to the bypassing capacity of exogenous HGF in medulloblastoma cell lines. It might be of great interest to anticipate on these results in developing novel clinical trials with a combination of MET and EGFR inhibitors in medulloblastoma.

Basal cell nevus syndrome or Gorlin syndrome

Basal cell nevus syndrome (BCNS) or Gorlin syndrome is a rare neurocutaneous syndrome sometimes known as the fifth phacomatosis, inherited in autosomal dominant fashion with complete penetrance and variable expressivity. Gorlin syndrome is characterized by development of multiple basal cell carcinomas (BCCs), jaw cysts, palmar or plantar pits, calcification of falx cerebri, various developmental skeletal abnormalities such as bifid rib, hemi- or bifid vertebra and predisposition to the development of various tumors. BCNS is caused by a mutation in the PTCH1 gene localized to 9q22.3. Its estimated prevalence varies between 1/55600 and 1/256000 with an equal male to female ratio. The medulloblastoma variant seen in Gorlin syndrome patients is of the desmoplastic type, characteristically presenting during the first 3 years of life. Therefore, children with desmoplastic medulloblastoma should be carefully screened for other features of BCNS. Radiation therapy for desmoplastic medulloblastoma should be avoided in BCNS patients as it may induce development of invasive BCCs and other tumors in the skin area exposed to radiation. This syndrome is a multisystem disorder so involvement of multiple specialists with a multimodal approach to detect and treat various manifestations at early stages will reduce the long-term sequelae and severity of the condition. Life expectancy is not significantly altered but morbidity from complications and cosmetic scarring can be substantial.