Disease Evolution Monitored by Serial Cerebrospinal Fluid Liquid Biopsies in Two Cases of Recurrent Medulloblastoma.

Medulloblastoma is the most common malignant brain tumor in childhood. Initial treatment generally includes surgery, irradiation, and chemotherapy. Approximately 20-30% of patients will experience a recurrence, which portends a very poor prognosis. The current standard of care for evaluation for relapse includes radiographic surveillance with magnetic resonance imaging at regular intervals. The presence of circulating tumor DNA in the cerebrospinal fluid has been demonstrated to be a predictor of a higher risk of progression in a research setting for patients with medulloblastoma treated on a prospective single institution clinical trial. We have previously published and clinically validated a liquid-biopsy-based genetic assay utilizing low-pass whole genome sequencing to detect copy number alterations in circulating tumor DNA. Here, we present two teenage patients with posterior fossa medulloblastoma with recurrent disease who have been monitored with serial liquid biopsies showing tumor evolution over time, demonstrating the clinical utility of these approaches.

The OTX2 Gene Induces Tumor Growth and Triggers Leptomeningeal Metastasis by Regulating the mTORC2 Signaling Pathway in Group 3 Medulloblastomas.

Medulloblastoma (MB) encompasses diverse subgroups, and leptomeningeal disease/metastasis (LMD) plays a substantial role in associated fatalities. Despite extensive exploration of canonical genes in MB, the molecular mechanisms underlying LMD and the involvement of the orthodenticle homeobox 2 (OTX2) gene, a key driver in aggressive MB Group 3, remain insufficiently understood. Recognizing OTX2's pivotal role, we investigated its potential as a catalyst for aggressive cellular behaviors, including migration, invasion, and metastasis. OTX2 overexpression heightened cell growth, motility, and polarization in Group 3 MB cells. Orthotopic implantation of OTX2-overexpressing cells in mice led to reduced median survival, accompanied by the development of spinal cord and brain metastases. Mechanistically, OTX2 acted as a transcriptional activator of the Mechanistic Target of Rapamycin (mTOR) gene's promoter and the mTORC2 signaling pathway, correlating with upregulated downstream genes that orchestrate cell motility and migration. Knockdown of mTOR mRNA mitigated OTX2-mediated enhancements in cell motility and polarization. Analysis of human MB tumor samples (N = 952) revealed a positive correlation between OTX2 and mTOR mRNA expression, emphasizing the clinical significance of OTX2's role in the mTORC2 pathway. Our results reveal that OTX2 governs the mTORC2 signaling pathway, instigating LMD in Group 3 MBs and offering insights into potential therapeutic avenues through mTORC2 inhibition.

PUMC-MB1 is a novel group 3 medulloblastoma preclinical model, sensitive to PI3K/mTOR dual inhibitor.

PURPOSE: Medulloblastoma (MB), a common and heterogeneous posterior fossa tumor in pediatric patients, presents diverse prognostic outcomes. To advance our understanding of MB's intricate biology, the development of novel patient tumor-derived culture MB models with necessary data is still an essential requirement. METHODS: We continuously passaged PUMC-MB1 in vitro in order to establish a continuous cell line. We examined the in vitro growth using Cell Counting Kit-8 (CCK-8) and in vivo growth with subcutaneous and intracranial xenograft models. The xenografts were investigated histopathologically with Hematoxylin and Eosin (HE) staining and immunohistochemistry (IHC). Concurrently, we explored its molecular features using Whole Genome Sequencing (WGS), targeted sequencing, and RNA sequecing. Guided by bioinformatics analysis, we validated PUMC-MB1's drug sensitivity in vitro and in vivo. RESULTS: PUMC-MB1, derived from a high-risk MB patient, displayed a population doubling time (PDT) of 48.18 h and achieved 100% tumor growth in SCID mice within 20 days. HE and Immunohistochemical examination of the original tumor and xenografts confirmed the classification of PUMC-MB1 as a classic MB. Genomic analysis via WGS revealed concurrent MYC and OTX2 amplifications. The RNA-seq data classified it within the Group 3 MB subgroup, while according to the WHO classification, it fell under the Non-WNT/Non-SHH MB. Comparative analysis with D283 and D341med identified 4065 differentially expressed genes, with notable enrichment in the PI3K-AKT pathway. Cisplatin, 4-hydroperoxy cyclophosphamide/cyclophosphamide, vincristine, and dactolisib (a selective PI3K/mTOR dual inhibitor) significantly inhibited PUMC-MB1 proliferation in vitro and in vivo. CONCLUSIONS: PUMC-MB1, a novel Group 3 (Non-WNT/Non-SHH) MB cell line, is comprehensively characterized for its growth, pathology, and molecular characteristics. Notably, dactolisib demonstrated potent anti-proliferative effects with minimal toxicity, promising a potential therapeutic avenue. PUMC-MB1 could serve as a valuable tool for unraveling MB mechanisms and innovative treatment strategies.

Development of Orthotopic Patient-Derived Xenograft Models of Pediatric Intracranial Tumors.

The development of clinically relevant and reliable models of central nervous system tumors has been instrumental in advancing the field of Neuro-Oncology. The orthotopic intracranial injection is widely used to study the growth, invasion, and spread of tumors in a controlled environment. Orthotopic models are performed to examine tumor cells isolated from a specific region in a patient in the same site or location in an animal model. Orthotopic brain tumor models are also utilized for preclinical testing of therapeutics as they closely recapitulate the behavior of such cancer and the brain environment of patients. Below, we describe our experiences in the development of murine models of pediatric brain tumors including diffuse midline glioma (DMG), glioblastoma (GBM), and medulloblastoma. The method provides an overview of intracranial stereotactic injections in mice.

Group 3 medulloblastoma transcriptional networks collapse under domain specific EP300/CBP inhibition.

Chemical discovery efforts commonly target individual protein domains. Many proteins, including the EP300/CBP histone acetyltransferases (HATs), contain several targetable domains. EP300/CBP are critical gene-regulatory targets in cancer, with existing high potency inhibitors of either the catalytic HAT domain or protein-binding bromodomain (BRD). A domain-specific inhibitory approach to multidomain-containing proteins may identify exceptional-responding tumor types, thereby expanding a therapeutic index. Here, we discover that targeting EP300/CBP using the domain-specific inhibitors, A485 (HAT) or CCS1477 (BRD) have different effects in select tumor types. Group 3 medulloblastoma (G3MB) cells are especially sensitive to BRD, compared with HAT inhibition. Structurally, these effects are mediated by the difluorophenyl group in the catalytic core of CCS1477. Mechanistically, bromodomain inhibition causes rapid disruption of genetic dependency networks that are required for G3MB growth. These studies provide a domain-specific structural foundation for drug discovery efforts targeting EP300/CBP and identify a selective role for the EP300/CBP bromodomain in maintaining genetic dependency networks in G3MB.

LOXL1-AS1 contributes to metastasis in sonic-hedgehog medulloblastoma by promoting cancer stem-like phenotypes.

BACKGROUND: Medulloblastomas (MBs) are one of the most common malignant brain tumor types in children. MB prognosis, despite improvement in recent years, still depends on clinical and biological risk factors. Metastasis is the leading cause of MB-related deaths, which highlights an unmet need for risk stratification and targeted therapy to improve clinical outcomes. Among the four molecular subgroups, sonic-hedgehog (SHH)-MB harbors clinical and genetic heterogeneity with a subset of high-risk cases. Recently, long non-coding (lnc)RNAs were implied to contribute to cancer malignant progression, but their role in MB remains unclear. This study aimed to identify pro-malignant lncRNAs that have prognostic and therapeutic significance in SHH-MB. METHODS: The Daoy SHH-MB cell line was engineered for ectopic expression of MYCN, a genetic signature of SHH-MB. MYCN-associated lncRNA genes were identified using RNA-sequencing data and were validated in SHH-MB cell lines, MB tissue samples, and patient cohort datasets. SHH-MB cells with genetic manipulation of the candidate lncRNA were evaluated for metastatic phenotypes in vitro, including cell migration, invasion, sphere formation, and expressions of stemness markers. An orthotopic xenograft mouse model was used to evaluate metastasis occurrence and survival. Finally, bioinformatic screening and in vitro assays were performed to explore downstream mechanisms. RESULTS: Elevated lncRNA LOXL1-AS1 expression was identified in MYCN-expressing Daoy cells and MYCN-amplified SHH-MB tumors, and was significantly associated with lower survival in SHH-MB patients. Functionally, LOXL1-AS1 promoted SHH-MB cell migration and cancer stemness in vitro. In mice, MYCN-expressing Daoy cells exhibited a high metastatic rate and adverse effects on survival, both of which were suppressed under LOLX1-AS1 perturbation. Integrative bioinformatic analyses revealed associations of LOXL1-AS1 with processes of cancer stemness, cell differentiation, and the epithelial-mesenchymal transition. LOXL1-AS1 positively regulated the expression of transforming growth factor (TGF)-ß2. Knockdown of TGF-ß2 in SHH-MB cells significantly abrogated their LOXL1-AS1-mediated prometastatic functions. CONCLUSIONS: This study proved the functional significance of LOXL1-AS1 in SHH-MB metastasis by its promotion of TGF-ß2-mediated cancer stem-like phenotypes, providing both prognostic and therapeutic potentials for targeting SHH-MB metastasis.

Germline biallelic BRCA2 pathogenic variants and medulloblastoma: an international cohort study.

Constitutional heterozygous pathogenic variants in genes coding for some components of the Fanconi anemia-BRCA signaling pathway, which repairs DNA interstrand crosslinks, represent risk factors for common cancers, including breast, ovarian, pancreatic and prostate cancer. A high cancer risk is also a main clinical feature in patients with Fanconi anemia (FA), a rare condition characterized by bone marrow failure, endocrine and physical abnormalities. The mainly recessive condition is caused by germline pathogenic variants in one of 21 FA-BRCA pathway genes. Among patients with FA, the highest cancer risks are observed in patients with biallelic pathogenic variants in BRCA2 or PALB2. These patients develop a range of embryonal tumors and leukemia during the first decade of life, however, little is known about specific clinical, genetic and pathologic features or toxicities. Here, we present genetic, clinical, pathological and treatment characteristics observed in an international cohort of eight patients with FA due to biallelic BRCA2 pathogenic variants and medulloblastoma (MB), an embryonal tumor of the cerebellum. Median age at MB diagnosis was 32.5 months (range 7-58 months). All patients with available data had sonic hedgehog-MB. Six patients received chemotherapy and one patient also received proton radiation treatment. No life-threatening toxicities were documented. Prognosis was poor and all patients died shortly after MB diagnosis (median survival time 4.5 months, range 0-21 months) due to MB or other neoplasms. In conclusion, MB in patients with biallelic BRCA2 pathogenic variants is a lethal disease. Future experimental treatments are necessary to help these patients.

A therapeutically targetable positive feedback loop between lnc-HLX-2-7, HLX, and MYC that promotes group 3 medulloblastoma.

Recent studies suggest that long non-coding RNAs (lncRNAs) contribute to medulloblastoma (MB) formation and progression. We have identified an lncRNA, lnc-HLX-2-7, as a potential therapeutic target in group 3 (G3) MBs. lnc-HLX-2-7 RNA specifically accumulates in the promoter region of HLX, a sense-overlapping gene of lnc-HLX-2-7, which activates HLX expression by recruiting multiple factors, including enhancer elements. RNA sequencing and chromatin immunoprecipitation reveal that HLX binds to and activates the promoters of several oncogenes, including TBX2, LIN9, HOXM1, and MYC. Intravenous treatment with cerium-oxide-nanoparticle-coated antisense oligonucleotides targeting lnc-HLX-2-7 (CNP-lnc-HLX-2-7) inhibits tumor growth by 40%-50% in an intracranial MB xenograft mouse model. Combining CNP-lnc-HLX-2-7 with standard-of-care cisplatin further inhibits tumor growth and significantly prolongs mouse survival compared with CNP-lnc-HLX-2-7 monotherapy. Thus, the lnc-HLX-2-7-HLX-MYC axis is important for regulating G3 MB progression, providing a strong rationale for using lnc-HLX-2-7 as a therapeutic target for G3 MBs.

Identification and validation of a metabolism-related gene signature for predicting the prognosis of paediatric medulloblastoma.

Medulloblastoma (MB) is a malignant brain tumour that is highly common in children and has a tendency to spread to the brain and spinal cord. MB is thought to be a metabolically driven brain tumour. Understanding tumour cell metabolic patterns and characteristics can provide a promising foundation for understanding MB pathogenesis and developing treatments. Here, by analysing RNA-seq data of MB samples from the Gene Expression Omnibus (GEO) database, 12 differentially expressed metabolic-related genes (DE-MRGs) were chosen for the construction of a predictive risk score model for MB. This model demonstrated outstanding accuracy in predicting the outcomes of MB patients and served as a standalone predictor. An evaluation of functional enrichment revealed that the risk score showed enrichment in pathways related to cancer promotion and the immune response. In addition, a high risk score was an independent poor prognostic factor for MB in patients with different ages, sexes, metastasis stages and subgroups (SHH and Group 4). Consistently, the metabolic enzyme ornithine decarboxylase (ODC1) was upregulated in MB patients with poor survival time. Inhibition of ODC1 in primary and metastatic MB cell lines decreased cell proliferation, migration and invasion but increased immune infiltration. This study could aid in identifying metabolic targets for MB as well as optimizing risk stratification systems and individual treatment plans for MB patients via the use of a metabolism-related gene prognostic risk score signature.

Medulloblastoma in a child with osteoma cutis - a rare association due to loss of GNAS expression.

OBJECTIVES: Inactivating GNAS mutations result in varied phenotypes depending on parental origin. Maternally inherited mutations typically lead to hormone resistance and Albright's hereditary osteodystrophy (AHO), characterised by short stature, round facies, brachydactyly and subcutaneous ossifications. Paternal inheritance presents with features of AHO or ectopic ossification without hormone resistance. This report describes the case of a child with osteoma cutis and medulloblastoma. The objective of this report is to highlight the emerging association between inactivating germline GNAS mutations and medulloblastoma, aiming to shed light on its implications for tumor biology and promote future development of targeted surveillance strategies to improve outcomes in paediatric patients with these mutations. CASE PRESENTATION: A 12-month-old boy presented with multiple plaque-like skin lesions. Biopsy confirmed osteoma cutis, prompting genetic testing which confirmed a heterozygous inactivating GNAS mutation. At 2.5 years of age, he developed neurological symptoms and was diagnosed with a desmoplastic nodular medulloblastoma, SHH molecular group, confirmed by MRI and histology. Further analysis indicated a biallelic loss of GNAS in the tumor. CONCLUSIONS: This case provides important insights into the role of GNAS as a tumor suppressor and the emerging association between inactivating GNAS variants and the development of medulloblastoma. The case underscores the importance of careful neurological assessment and ongoing vigilance in children with known inactivating GNAS variants or associated phenotypes. Further work to establish genotype-phenotype correlations is needed to inform optimal management of these patients.

Plasma ctDNA Monitoring of a PTCH1-Mutant Metastatic Adult Medulloblastoma Showing a Durable Benefit With Vismodegib.

Adult medulloblastoma (MB) is a rare disease affecting 0.6 persons per million adults over 19 years of age. The SHH-activated/TP53-wild type is the most common subtype, accounting for 60% of adult MBs, being characterized by mutations in PTCH1, SMO, or the TERT promoter. Several small studies demonstrate objective but short-lived responses to SMO inhibitors such as vismodegib or sonidegib. Like other oncogene-addicted solid tumors, detection of the corresponding drivers through liquid biopsy could aid in the molecular diagnosis and monitoring of the disease through less invasive procedures. However, most studies have only evaluated cerebrospinal fluid as the ctDNA reservoir, and very limited evidence exists on the role of liquid biopsy in plasma in patients with primary central nervous system tumors, including MB. We present the case of a 26-year-old patient with a recurrent MB, in which next-generation sequencing (FoundationOne CDx) revealed a mutation in PTCH1, allowing the patient to be treated with vismodegib in second line, resulting in a durable benefit lasting for 1 year. Using an in-house digital PCR probe, the PTCH1 mutation could be tracked in ctDNA during treatment with first-line chemotherapy and while on treatment with vismodegib, demonstrating a precise correlation with the radiological and clinical behavior of the disease.

Increasing Sufu gene dosage reveals its unorthodox role in promoting polydactyly and medulloblastoma tumorigenesis.

Suppressor of fused (SUFU) is widely regarded as a key negative regulator of the sonic hedgehog (SHH) morphogenic pathway and a known tumor suppressor of medulloblastoma (MB). However, we report here that SUFU expression was markedly increased in 75% of specimens compiled in a tissue array comprising 49 unstratified MBs. The SUFU and GLI1 expression levels in this MB array showed strong positive correlation, which was also identified in a large public data set containing 736 MBs. We further report that increasing Sufu gene dosage in mice caused preaxial polydactyly, which was associated with the expansion of the Gli3 domain in the anterior limb bud and heightened Shh signaling responses during embryonic development. Increasing Sufu gene dosage also led to accelerated cerebellar development and, when combined with ablation of the Shh receptor encoded by Patched1 (Ptch1), promoted MB tumorigenesis. These data reveal multifaceted roles of SUFU in promoting MB tumorigenesis by enhancing SHH signaling. This revelation clarifies potentially counterintuitive clinical observation of high SUFU expression in MBs and may pave way for novel strategies to reduce or reverse MB progression.

Heterogeneity and tumoral origin of medulloblastoma in the single-cell era.

Medulloblastoma is one of the most common malignant pediatric brain tumors derived from posterior fossa. The current treatment includes maximal safe surgical resection, radiotherapy, whole cranio-spinal radiation and adjuvant with chemotherapy. However, it can only limitedly prolong the survival time with severe side effects and relapse. Defining the intratumoral heterogeneity, cellular origin and identifying the interaction network within tumor microenvironment are helpful for understanding the mechanisms of medulloblastoma tumorigenesis and relapse. Due to technological limitations, the mechanisms of cellular heterogeneity and tumor origin have not been fully understood. Recently, the emergence of single-cell technology has provided a powerful tool for achieving the goal of understanding the mechanisms of tumorigenesis. Several studies have demonstrated the intratumoral heterogeneity and tumor origin for each subtype of medulloblastoma utilizing the single-cell RNA-seq, which has not been uncovered before using conventional technologies. In this review, we present an overview of the current progress in understanding of cellular heterogeneity and tumor origin of medulloblastoma and discuss novel findings in the age of single-cell technologies.

PTCH1-mutant human cerebellar organoids exhibit altered neural development and recapitulate early medulloblastoma tumorigenesis.

Patched 1 (PTCH1) is the primary receptor for the sonic hedgehog (SHH) ligand and negatively regulates SHH signalling, an essential pathway in human embryogenesis. Loss-of-function mutations in PTCH1 are associated with altered neuronal development and the malignant brain tumour medulloblastoma. As a result of differences between murine and human development, molecular and cellular perturbations that arise from human PTCH1 mutations remain poorly understood. Here, we used cerebellar organoids differentiated from human induced pluripotent stem cells combined with CRISPR/Cas9 gene editing to investigate the earliest molecular and cellular consequences of PTCH1 mutations on human cerebellar development. Our findings demonstrate that developmental mechanisms in cerebellar organoids reflect in vivo processes of regionalisation and SHH signalling, and offer new insights into early pathophysiological events of medulloblastoma tumorigenesis without the use of animal models.

Development of a high-throughput screening platform to identify new therapeutic agents for Medulloblastoma Group 3.

Pediatric brain tumors (PBTs) represent about 25 % of all pediatric cancers and are the most common solid tumors in children and adolescents. Medulloblastoma (MB) is the most frequently occurring malignant PBT, accounting for almost 10 % of all pediatric cancer deaths. MB Group 3 (MB G3) accounts for 25-30 % of all MB cases and has the worst outcome, particularly when associated with MYC amplification. However, no targeted treatments for this group have been developed so far. Here we describe a unique high throughput screening (HTS) platform specifically designed to identify new therapies for MB G3. The platform incorporates optimized and validated 2D and 3D efficacy and toxicity models, that account for tumor heterogenicity, limited efficacy and unacceptable toxicity from the very early stage of drug discovery. The platform has been validated by conducting a pilot HTS campaign with a 1280 lead-like compound library. Results showed 8 active compounds, targeting MB reported targets and several are currently approved or in clinical trials for pediatric patients with PBTs, including MB. Moreover, hits were combined to avoid tumor resistance, identifying 3 synergistic pairs, one of which is currently under clinical study for recurrent MB and other PBTs.

Phosphorylation of human glioma-associated oncogene 1 on Ser937 regulates Sonic Hedgehog signaling in medulloblastoma.

Aberrant activation of sonic hedgehog (SHH) signaling and its effector transcriptional factor GLI1 are essential for oncogenesis of SHH-dependent medulloblastoma (MBSHH) and basal cell carcinoma (BCC). Here, we show that SHH inactivates p38α (MAPK14) in a smoothened-dependent manner, conversely, p38α directly phosphorylates GLI1 on Ser937/Ser941 (human/mouse) to induce GLI1's proteasomal degradation and negates the transcription of SHH signaling. As a result, Gli1S941E loss-of-function knock-in significantly reduces the incidence and severity of smoothened-M2 transgene-induced spontaneous MBSHH, whereas Gli1S941A gain-of-function knock-in phenocopies Gli1 transgene in causing BCC-like proliferation in skin. Correspondingly, phospho-Ser937-GLI1, a destabilized form of GLI1, positively correlates to the overall survival rate of children with MBSHH. Together, these findings indicate that SHH-induced p38α inactivation and subsequent GLI1 dephosphorylation and stabilization in controlling SHH signaling and may provide avenues for future interventions of MBSHH and BCC.

Medulloblastoma and other neoplasms in patients with heterozygous germline SUFU variants: A scoping review.

In 2002, heterozygous suppressor of fused variants (SUFU+/-) in the germline were described to have a tumor suppressor role in the development of pediatric medulloblastoma (MB). Other neoplasms associated with pathologic germline SUFU+/- variants have also been described among patients with basal cell nevus syndrome (BCNS; BCNS is also known as Gorlin syndrome, nevoid basal cell carcinoma [BCC] syndrome or Gorlin-Goltz syndrome; OMIM 109400), an autosomal-dominant cancer predisposition syndrome. The phenotype of patients with germline SUFU+/- variants is very poorly characterized due to a paucity of large studies with long-term follow-up. As such, there is a clinical need to better characterize the spectrum of neoplasms among patients with germline SUFU+/- variants so that clinicians can provide accurate counseling and optimize tumor surveillance strategies. The objective of this study is to perform a scoping review to map the evidence on the rate of medulloblastoma and to describe the spectrum of other neoplasms among patients with germline SUFU+/- variants. A review of all published literature in PubMed (MEDLINE), EMBASE, Cochrane, and Web of Science were searched from the beginning of each respective database until October 9, 2021. Studies of pediatric and adult patients with a confirmed germline SUFU+/- variant who were evaluated for the presence of any neoplasm (benign or malignant) were included. There were 176 patients (N = 30 studies) identified with a confirmed germline SUFU+/- variant who met inclusion criteria. Data were extracted from two cohort studies, two case-control studies, 18 case series, and eight case reports. The median age at diagnosis of a germline SUFU+/- variant was 4.5 years where 44.4% identified as female and 13.4% of variants were de novo. There were 34 different neoplasms (benign and malignant) documented among patients with confirmed germline SUFU+/- variants, and the most common were medulloblastoma (N = 59 patients), BCC (N = 21 patients), and meningioma (N = 19 patients). The median age at medulloblastoma diagnosis was 1.42 years (range 0.083-3; interquartile range 1.2). When data were available for these three most frequent neoplasms (N = 95 patients), 31 patients (32.6%) had neither MB, BCC nor meningioma; 51 patients (53.7%) had one of medulloblastoma or BCC or meningioma; eight patients (8.4%) had two of medulloblastoma or BCC or meningioma, and five patients (5.3%) had medulloblastoma and BCC and meningioma. This is the first study to synthesize the data on the frequency and spectrum of neoplasms specifically among patients with a confirmed germline SUFU+/- variant. This scoping review is a necessary step forward in optimizing evidence-based tumor surveillance strategies for medulloblastoma and estimating the risk of other neoplasms that could impact patient outcomes.

Late effects of medulloblastoma treatment: multidisciplinary approach of survivors.

PURPOSE: Medulloblastoma is one of the brain tumors with increased life expectancy due to improvements in treatment approaches. Besides the promising results, various undesirable effects can be encountered. This study's aim is to review long-term follow-up outcomes of our cases with medulloblastoma. METHODS: Age at diagnosis, histological type of medulloblastoma, resection extension, chemotherapy and radiotherapy schemes, follow-up duration, and endocrinological, neuropsychiatric, cardiological, auditory, and visual examination results were evaluated in 20 patients diagnosed between 2007 and 2018 and followed 5 years and more. RESULTS: Twenty of 53 patients were included to the study. Eleven (55%) were male. Mean age at diagnosis was 6.95 years; mean age at the time of the study was 14 years. Mean follow-up time was 8.95 years. In terms of surgery, 14 (70%) were gross total, 1 (5%) was near total, and 2 (10%) were subtotal resection. In histopathological examination, 14 (70%) were classical medulloblastoma, 4 (20%) were desmoplastic medulloblastoma, and 1 (5%) was anaplastic medulloblastoma. With regard to endocrinological evaluation, 15 (75%) patients had hypothyroidism, 5 (25%) had growth hormone deficiency, 7 (35%) had clinical growth hormone deficiency, and 5 (25%) had sex hormone disorders. In neuropsychiatric examination, 11 (55%) patients had neurological sequelae, 18 (90%) patients had psychiatric issues, and 14 (70%) patients had two or more neuropsychiatric problems simultaneously. One (5%) patient had mitral valve insufficiency. Twelve patients (60%) had hearing loss. According to visual examination, 6 (30%) patients had refraction problem, 4 (20%) had cataract, and 1 (5%) had dry eye. CONCLUSION: Careful monitoring of long-term side effects is important for improving the quality of life of medulloblastoma patients. Besides endocrinological and other somatic sequelae of the disease and treatment, increased neuropsychiatric problems showed us that only cure is not the issue while treating childhood medulloblastoma.

Tumor-associated astrocytes promote tumor progression of Sonic Hedgehog medulloblastoma by secreting lipocalin-2.

Sonic Hedgehog (SHH) subgroup of medulloblastoma (MB) accounts for about 25% of all subgroups of MB. Tumor microenvironment (TME) may play a key role in the tumor progression and therapeutic resistance. Tumor-associated astrocytes (TAAs) are reshaped to drive tumor progression through multiple paracrine signals. However, the mechanism by which TAAs modulate MB cells remains elusive. Here, we illuminated that TAAs showed a specific and dynamic pattern during SHH-MB development. Most TAAs gathered to the tumor margin during the tumor progression, rather than evenly distributed in the early-stage tumors. We further demonstrated that lipocalin-2 (LCN2) secreted by TAAs could promote the tumor growth and was correlated with the poor prognosis of MB patients. Knocking down LCN2 in TAAs in vitro impeded the proliferation and migration abilities of MB cells. In addition, we identified that TAAs accelerated the tumor growth by secreting LCN2 via STAT3 signaling pathway. Accordingly, blockade of STAT3 signaling by its inhibitor WP1066 and AAV-Lcn2 shRNA, respectively, in TAAs abrogated the effects of LCN2 on tumor progression in vitro and in vivo. In summary, we for the first time clarified that LCN2, secreted by TAAs, could promote MB tumor progression via STAT3 pathway and has potential prognostic value. Our findings unveiled a new sight in reprogramming the TME of SHH-MB and provided a potential therapeutic strategy targeting TAAs.