PURPOSE: The BT-40 low-grade childhood astrocytoma xenograft model expresses mutated BRAF(V600E) and is highly sensitive to the MEK inhibitor selumetinib (AZD6244). In this study, we developed and characterized selumetinib resistance and explored approaches to circumventing the mechanisms of acquired resistance.

EXPERIMENTAL DESIGN: BT-40 xenografts were selected in vivo for selumetinib resistance. Resistant tumors were obtained and characterized, as were tumors that reverted to ...

OBJECT: Brain tumors in infants are often large, high grade, and vascular, making complete resection difficult and placing children at risk for neurological complications and excessive blood loss. Neoadjuvant chemotherapy may reduce tumor vascularity and volume, which can facilitate resection. The authors evaluated how an ongoing institutional prospective chemotherapy trial would affect patients who did not have a gross-total resection (GTR) immediately and who therefore required further ...

INTRODUCTION: 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 ...

Understanding the biology that underlies histologically similar but molecularly distinct subgroups of cancer has proven difficult because their defining genetic alterations are often numerous, and the cellular origins of most cancers remain unknown. We sought to decipher this heterogeneity by integrating matched genetic alterations and candidate cells of origin to generate accurate disease models. First, we identified subgroups of human ependymoma, a form of neural tumour that arises ...

Background: Diffuse intrinsic pontine glioma (DIPG) is a high-grade brainstem glioma of children with dismal prognosis. There is no single unifying model about the cell of origin of DIPGs. Proliferating cells in the developing human and mouse pons, the site of DIPGs, express neural stem/progenitor cell (NPC) markers, including Sox2, nestin, vimentin, Olig2, and glial fibrillary acidic protein, in an overlapping and non-overlapping manner, suggesting progenitor cell heterogeneity in the ...

There is a paucity of data regarding patterns of progression in children with high-grade glioma (HGG) or diffuse intrinsic pontine glioma (DIPG) treated with bevacizumab (BVZ) at diagnosis. We performed a retrospective study of 20 children with HGG or DIPG who received BVZ-based therapy at diagnosis on, or according to, a bi-institutional study. Magnetic resonance imaging (MRI) characteristics of first and most recent progressions were reviewed. Comparison was made to a control group of ...

Children with high-grade glioma, including diffuse intrinsic pontine glioma (DIPG), have a poor prognosis despite multimodal therapy. Identifying novel therapeutic targets is critical to improve their outcome. We evaluated prognostic roles of telomere maintenance mechanisms in children with HGG, including DIPG. A multi-institutional retrospective study was conducted involving 50 flash-frozen HGG (35 non-brainstem; 15 DIPG) tumors from 45 children (30 non-brainstem; 15 DIPG). Telomerase ...

Although bevacizumab has not proven effective in adults with newly diagnosed high-grade gliomas (HGG), feasibility in newly diagnosed children with diffuse intrinsic pontine gliomas (DIPG) or HGG has not been reported in a prospective study. In a safety and feasibility study, children and young adults with newly diagnosed HGG received radiotherapy (RT) with bevacizumab (10 mg/kg: days 22, 36) and temozolomide (75–90 mg/m2/day for 42 days) followed by bevacizumab (10 mg/kg, days 1, 15), ...

PURPOSE: Diffuse intrinsic pontine glioma (DIPG) is a devastating pediatric disease, with a median survival of <1 year. Here, we review our institution's DIPG experience over an 8-year interval and perform a systematic review of the literature, specifically evaluating reports of reirradiation (reRT) for DIPG.

METHODS AND MATERIALS: We retrospectively reviewed the medical records of 26 patients who underwent definitive intensity modulated radiation therapy (IMRT) for DIPG at a single ...

Medulloblastoma, the most common pediatric malignant brain tumor often arises sporadically; however, in a subgroup of patients, there exist familial conditions such as Fanconi anemia with biallelic BRCA2 mutation that predispose patients to developing medulloblastoma. Biallelic inactivation of BRCA2 in Fanconi anemia has been previously described in only 11 patients with medulloblastoma in the literature to date. Here we report two siblings diagnosed with central nervous system embryonal ...

Pediatric high-grade gliomas (pHGGs) are aggressive neoplasms representing approximately 20% of brain tumors in children. Current therapies offer limited disease control, and patients have a poor prognosis. Empiric use of targeted therapy, especially at progression, is increasingly practiced despite a paucity of data regarding temporal and therapy-driven genomic evolution in pHGGs. To study the genetic landscape of pHGGs at recurrence, we performed whole exome and methylation analyses on ...

BACKGROUND: Female survivors of central nervous system (CNS) tumors are at an increased risk for gonadal damage and variations in the timing of puberty following radiotherapy and alkylating agent-based chemotherapy.

PROCEDURE: Clinical and laboratory data were obtained from 30 evaluable female patients with newly diagnosed embryonal CNS tumors treated on a prospective protocol (SJMB 96) at St. Jude Children's Research Hospital (SJCRH). Pubertal development was evaluated by Tanner ...

Diffuse intrinsic pontine glioma (DIPG) is a poor-prognosis pediatric brain tumor. No effective curative therapy is currently available and no therapeutic advances have been made in several decades. BMI-1 is a member of the multimeric protein complex Polycomb repressor complex 1. It is highly expressed in a number of diseases and malignancies and has been implicated in self-renewal of normal and cancer cells, and in DNA damage signaling. The role of BMI-1 in DIPG is largely unknown. ...

Pediatric tectal plate gliomas are indolent slow-growing gliomas that often present with increased intracranial pressure or incidentally on routine brain imaging. We investigated clinical outcomes, endocrinopathies, and neuropsychological sequelae associated with tectal plate gliomas. Twenty-six patients with tectal plate glioma were identified in a 20-year retrospective review. Clinical outcomes, treatments, endocrine function, neuropsychological testing outcomes and radiographic ...

PurposeCyclin-dependent kinase-retinoblastoma (CDK-RB) pathway is dysregulated in some diffuse intrinsic pontine gliomas (DIPG). We evaluated safety, feasibility, and early efficacy of the CDK4/6-inhibitor ribociclib, administered following radiotherapy in newly-diagnosed DIPG patients.MethodsFollowing radiotherapy, eligible patients received ribociclib in 28-day cycles (350 mg/m2; 21 days on/7 days off). Feasibility endpoints included tolerability for at least 6 courses, and a less than ...