Despite increasing evidence that antitumor immune control exists in the pediatric brain, these findings have yet to be exploited successfully in the clinic. A barrier to development of ...immunotherapeutic strategies in pediatric brain tumors is that the immunophenotype of these tumors' microenvironment has not been defined. To address this, the current study used multicolor FACS of disaggregated tumor to systematically characterize the frequency and phenotype of infiltrating immune cells in the most common pediatric brain tumor types. The initial study cohort consisted of 7 pilocytic astrocytoma (PA), 19 ependymoma (EPN), 5 glioblastoma (GBM), 6 medulloblastoma (MED), and 5 nontumor brain (NT) control samples obtained from epilepsy surgery. Immune cell types analyzed included both myeloid and T cell lineages and respective markers of activated or suppressed functional phenotypes. Immune parameters that distinguished each of the tumor types were identified. PA and EPN demonstrated significantly higher infiltrating myeloid and lymphoid cells compared with GBM, MED, or NT. Additionally, PA and EPN conveyed a comparatively activated/classically activated myeloid cell-skewed functional phenotype denoted in particular by HLA-DR and CD64 expression. In contrast, GBM and MED contained progressively fewer infiltrating leukocytes and more muted functional phenotypes similar to that of NT. These findings were recapitulated using whole tumor expression of corresponding immune marker genes in a large gene expression microarray cohort of pediatric brain tumors. The results of this cross-tumor comparative analysis demonstrate that different pediatric brain tumor types exhibit distinct immunophenotypes, implying that specific immunotherapeutic approaches may be most effective for each tumor type.
Abstract
Atypical teratoid rhabdoid tumor (ATRT) is a rare, highly malignant central nervous system cancer arising in infants and younger children, historically considered to be homogeneous, ...monogenic, and incurable. Recent use of intensified therapies has modestly improved survival for ATRT; however, a majority of patients will still succumb to their disease. While ATRTs almost universally exhibit loss of SMARCB1 (BAF47/INI1/SNF5), recent whole genome, transcriptome, and epigenomic analyses of large cohorts reveal previously underappreciated molecular heterogeneity. These discoveries provide novel insights into how SMARCB1 loss drives oncogenesis and confer specific therapeutic vulnerabilities, raising exciting prospects for molecularly stratified treatment for patients with ATRT.
Abstract
Radiation-induced high-grade gliomas (RIGs) are an incurable late complication of cranial radiation therapy. We performed DNA methylation profiling, RNA-seq, and DNA sequencing on 32 RIG ...tumors and an in vitro drug screen in two RIG cell lines. We report that based on DNA methylation, RIGs cluster primarily with the pediatric receptor tyrosine kinase I high-grade glioma subtype. Common copy-number alterations include Chromosome (Ch.) 1p loss/1q gain, and Ch. 13q and Ch. 14q loss; focal alterations include
PDGFRA
and
CDK4
gain and
CDKN2A
and
BCOR
loss. Transcriptomically, RIGs comprise a stem-like subgroup with lesser mutation burden and Ch. 1p loss and a pro-inflammatory subgroup with greater mutation burden and depleted DNA repair gene expression. Chromothripsis in several RIG samples is associated with extrachromosomal circular DNA-mediated amplification of
PDGFRA
and
CDK4
. Drug screening suggests microtubule inhibitors/stabilizers, DNA-damaging agents, MEK inhibition, and, in the inflammatory subgroup, proteasome inhibitors, as potentially effective therapies.
Background
The use of next‐generation sequencing for fusion identification is being increasingly applied and aids our understanding of tumor biology. Some fusions are responsive to approved targeted ...agents, while others have future potential for therapeutic targeting. Although some pediatric central nervous system tumors may be cured with surgery alone, many require adjuvant therapy associated with acute and long‐term toxicities. Identification of targetable fusions can shift the treatment paradigm toward earlier integration of molecularly targeted agents.
Methods
Patients diagnosed with glial, glioneuronal, and ependymal tumors between 2002 and 2019 were retrospectively reviewed for fusion testing. Testing was done primarily using the ArcherDx FusionPlex Solid Tumor panel, which assesses fusions in 53 genes. In contrast to many previously published series chronicling fusions in pediatric patients, we compared histological features and the tumor classification subtype with the specific fusion identified.
Results
We report 24 cases of glial, glioneuronal, or ependymal tumors from pediatric patients with identified fusions. With the exception of BRAF:KIAA1549 and pilocytic/pilomyxoid astrocytoma morphology, and possibly QKI‐MYB and angiocentric glioma, there was not a strong correlation between histological features/tumor subtype and the specific fusion. We report the unusual fusions of PPP1CB‐ALK, CIC‐LEUTX, FGFR2‐KIAA159, and MN1‐CXXC5 and detail their morphological features.
Conclusions
Fusion testing proved to be informative in a high percentage of cases. A large majority of fusion events in pediatric glial, glioneuronal, and ependymal tumors can be identified by relatively small gene panels.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Adamantinomatous craniopharyngioma (ACP) makes up between 6 and 8% of pediatric brain tumors and is the most common pediatric tumor arising in the sellar/suprasellar region of the brain. The 10-year ...survival for patients diagnosed with craniopharyngioma ranges between 64 and 92%, but complicating factors such as location, common cyst formation, and potential hypothalamic infiltration cause significant morbidity in this population. There are a number of therapeutic options for children with ACP, including surgery, radiation, and cyst directed therapies such as interferon and bleomycin. Research has raised concerns regarding the efficacy and side effects associated with these conventional therapies, as well as with the difficulty in treating recurrent cystic ACP. Evidence from our group and others has shown that the cystic and solid tumor components of craniopharyngioma have high levels of IL-6R and IL-6, providing a potential target for therapy. Tocilizumab, a humanized monoclonal antibody, acts against soluble and membrane bound IL-6R, and has been widely utilized in pediatric patients. Two patients with recurrent cystic ACP were offered systemically administered tocilizumab or a combination of tocilizumab and bevacizumab on a compassionate use basis. Both patients' tumors had a significant response, with decreased cyst burden, supporting the assertion that tocilizumab with or without bevacizumab may be an option for patients suffering from cystic ACP.
Diffuse intrinsic pontine glioma (DIPG) and midline high-grade glioma (mHGG) are lethal childhood brain tumors. Spatial genomic heterogeneity has been well-described in adult HGG but has not been ...comprehensively characterized in pediatric HGG. We performed whole exome sequencing on 38-matched primary, contiguous, and metastatic tumor sites from eight children with DIPG (n = 7) or mHGG (n = 1) collected using a unique MRI-guided autopsy protocol. Validation was performed using Sanger sequencing, Droplet Digital polymerase-chain reaction, immunohistochemistry, and fluorescent in-situ hybridization.
Median age at diagnosis was 6.1 years (range: 2.9-23.3 years). Median overall survival was 13.2 months (range: 11.2-32.2 months). Contiguous tumor infiltration and distant metastases were observed in seven and six patients, respectively, including leptomeningeal dissemination in three DIPGs. Histopathological heterogeneity was evident in seven patients, including intra-pontine heterogeneity in two DIPGs, ranging from World Health Organization grade II to IV astrocytoma. We found conservation of heterozygous K27M mutations in H3F3A (n = 4) or HIST1H3B (n = 3) across all primary, contiguous, and metastatic tumor sites in all DIPGs. ACVR1 (n = 2), PIK3CA (n = 2), FGFR1 (n = 2), and MET (n = 1) were also intra-tumorally conserved. ACVR1 was co-mutated with HIST1H3B (n = 2). In contrast, PDGFRA amplification and mutation were spatially heterogeneous, as were mutations in BCOR (n = 1), ATRX (n = 2), and MYC (n = 1). TP53 aberrations (n = 3 patients) varied by type and location between primary and metastatic tumors sites but were intra-tumorally conserved.
Spatial conservation of prognostically-relevant and therapeutically-targetable somatic mutations in DIPG and mHGG contrasts the significant heterogeneity of driver mutations seen in adult HGG and supports uniform implementation of diagnostic biopsy in DIPG and mHGG to classify molecular risk groups and guide therapeutic strategy.
Abstract Purpose Anterior mediastinal masses (AMM) pose a diagnostic challenge to surgeons, oncologists, anesthesiologists, intensivists, and interventional radiologists as induction of general ...anesthesia can cause airway obstruction and cardiovascular collapse. We hypothesized that in the majority of patients, diagnosis can be obtained through biopsy of extrathoracic tissue. Methods We performed a retrospective review of all patients in the solid tumor oncology clinic with a diagnosis of AMM between 2002 and 2012 including preoperative evaluation and management prior to obtaining a tissue diagnosis, clinical course and complications. Results We identified 69 patients with AMM (mean age 12.2 ± 4.4 years, 64% male) secondary to Hodgkin lymphoma (34), Non-Hodgkin lymphoma (26), and other diagnoses (9). The majority of patients (56, 81.2%) underwent biopsy of tissue outside of the mediastinal mass. Local anesthesia with sedation was used for successful biopsy in 21 (30%) patients. Four (5.8%) required repeat biopsy due to inadequate sample obtained at initial procedure. Three (4.4%) suffered respiratory complications with no fatalities or severe complications. Conclusions Our data demonstrate that in the majority of children with AMM, tissue biopsy can be successfully obtained from tissue outside of the mass itself with minimal complications and highlight the importance of multidisciplinary preoperative planning to minimize anesthetic risks.
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Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Leukemia is the most common childhood malignancy and acute lymphoblastic leukemia (ALL) represents the largest sub-type. Despite remarkable improvements over the last 40 years, standard therapy fails ...in 10-20% of newly diagnosed patients. Survival for children with relapsed ALL is poor, and the development and implementation of novel therapeutic strategies in pediatric ALL are critical to further advancements. Immunotherapeutic approaches have been central to more novel ALL therapies. However, more recent innovation in antibody engineering has improved potency and efficacy, and antibody-drug conjugates (ADCs) are an especially attractive option in severely immunocompromised patients. An even more sophisticated antibody design is that of bi-specific T-cell engaging or BiTE(®) antibodies, which directly recruit effector T cells to augment the anti-neoplastic effect. This review focuses on blinatumomab, a bi-specific anti-CD19/CD3 antibody that has shown efficacy in adult patients with precursor B-ALL and is currently being evaluated in the pediatric setting.
Purpose Diffuse intrinsic pontine glioma (DIPG) is a brainstem malignancy with a median survival of < 1 year. The International and European Society for Pediatric Oncology DIPG Registries ...collaborated to compare clinical, radiologic, and histomolecular characteristics between short-term survivors (STSs) and long-term survivors (LTSs). Materials and Methods Data abstracted from registry databases included patients from North America, Australia, Germany, Austria, Switzerland, the Netherlands, Italy, France, the United Kingdom, and Croatia. Results Among 1,130 pediatric and young adults with radiographically confirmed DIPG, 122 (11%) were excluded. Of the 1,008 remaining patients, 101 (10%) were LTSs (survival ≥ 2 years). Median survival time was 11 months (interquartile range, 7.5 to 16 months), and 1-, 2-, 3-, 4-, and 5-year survival rates were 42.3% (95% CI, 38.1% to 44.1%), 9.6% (95% CI, 7.8% to 11.3%), 4.3% (95% CI, 3.2% to 5.8%), 3.2% (95% CI, 2.4% to 4.6%), and 2.2% (95% CI, 1.4% to 3.4%), respectively. LTSs, compared with STSs, more commonly presented at age < 3 or > 10 years (11% v 3% and 33% v 23%, respectively; P < .001) and with longer symptom duration ( P < .001). STSs, compared with LTSs, more commonly presented with cranial nerve palsy (83% v 73%, respectively; P = .008), ring enhancement (38% v 23%, respectively; P = .007), necrosis (42% v 26%, respectively; P = .009), and extrapontine extension (92% v 86%, respectively; P = .04). LTSs more commonly received systemic therapy at diagnosis (88% v 75% for STSs; P = .005). Biopsies and autopsies were performed in 299 patients (30%) and 77 patients (10%), respectively; 181 tumors (48%) were molecularly characterized. LTSs were more likely to harbor a HIST1H3B mutation (odds ratio, 1.28; 95% CI, 1.1 to 1.5; P = .002). Conclusion We report clinical, radiologic, and molecular factors that correlate with survival in children and young adults with DIPG, which are important for risk stratification in future clinical trials.
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