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1.  Proceedings from the 2009 Genetic Syndromes of the Ras/MAPK Pathway: From Bedside to Bench and Back 
The RASopathies are a group of genetic syndromes caused by germline mutations in genes that encode components of the Ras/mitogen-activated protein kinase (MAPK) pathway. Some of these syndromes are neurofibromatosis type 1, Noonan syndrome, Costello syndrome, cardio-facio-cutaneous syndrome, LEOPARD syndrome and Legius syndrome. Their common underlying pathogenetic mechanism brings about significant overlap in phenotypic features and includes craniofacial dysmorphology, cardiac, cutaneous, musculoskeletal, GI and ocular abnormalities, and a predisposition to cancer. The proceedings from the symposium “Genetic Syndromes of the Ras/MAPK Pathway: From Bedside to Bench and Back” chronicle the timely and typical research symposium which brought together clinicians, basic scientists, physician-scientists, advocate leaders, trainees, students and individuals with Ras syndromes and their families. The goals, to discuss basic science and clinical issues, to set forth a solid framework for future research, to direct translational applications towards therapy and to set forth best practices for individuals with RASopathies was successfully meet with a commitment to begin to move towards clinical trials.
doi:10.1002/ajmg.a.33183
PMCID: PMC4051786  PMID: 20014119
Cardio-facio-cutaneous syndrome; clinical trial; Costello syndrome; neurofibromatosis type 1; Noonan syndrome; Legius syndrome; Ras/MAPK; signal transduction pathway; RASopathies; therapy
2.  A prognostic gene expression signature in infratentorial ependymoma 
Acta neuropathologica  2012;123(5):727-738.
Patients with ependymoma exhibit a wide range of clinical outcomes that is currently unexplained by clinical or histological factors. Little is known regarding molecular biomarkers that could predict clinical behavior. Since recent data suggests that these tumors display biological characteristics according to their location (cerebral vs. infratentorial vs. spinal cord), rather than explore a broad spectrum of ependymoma, we focused on molecular alterations in ependymomas arising in the infratentorial compartment. Unsupervised clustering of available gene expression microarray data revealed two major subgroups of infratentorial ependymoma. Group 1 tumors over expressed genes that were associated with mesenchyme, Group 2 tumors showed no distinct gene ontologies. To assess the prognostic significance of these gene expression subgroups, real-time reverse-transcriptase polymerase chain reaction assays were performed on genes defining the subgroups in a training set. This resulted in a 10-gene prognostic signature. Multivariate analysis showed that the 10-gene signature was an independent predictor of recurrence-free survival after adjusting for clinical factors. Evaluation of an external dataset describing subgroups of infratentorial ependymomas showed concordance of subgroup definition, including validation of the mesenchymal subclass. Importantly, the 10-gene signature was validated as a predictor of recurrence-free survival in this dataset. Taken together, the results indicate a link between clinical outcome and biologically-identified subsets of infratentorial ependymoma and offer the potential for prognostic testing to estimate clinical aggressiveness in these tumors.
doi:10.1007/s00401-012-0941-4
PMCID: PMC4013829  PMID: 22322993
Infratentorial ependymoma; Expression profiling; Gene expression signature; Prognostic genes; Microarray; Biomarker
3.  Survival and secondary tumors in children with medulloblastoma receiving radiotherapy and adjuvant chemotherapy: results of Children's Oncology Group trial A9961 
Neuro-Oncology  2012;15(1):97-103.
The purpose of the trial was to determine the survival and incidence of secondary tumors in children with medulloblastoma receiving radiotherapy plus chemotherapy. Three hundred seventy-nine eligible patients with nondisseminated medulloblastoma between the ages of 3 and 21 years were treated with 2340 cGy of craniospinal and 5580 cGy of posterior fossa irradiation. Patients were randomized between postradiation cisplatin and vincristine plus either CCNU or cyclophosphamide. Survival, pattern of relapse, and occurrence of secondary tumors were assessed. Five- and 10-year event-free survivals were 81 ± 2% and 75.8 ± 2.3%; overall survivals were 87 ± 1.8% and 81.3 ± 2.1%. Event-free survival was not impacted by chemotherapeutic regimen, sex, race, age at diagnosis, or gender. Seven patients had disease relapse beyond 5 years after diagnosis; relapse was local in 4 patients, local plus supratentorial in 2, and supratentorial alone in 1. Fifteen patients experienced secondary tumors as a first event at a median time of 5.8 years after diagnosis (11 >5 y postdiagnosis). All non-CNS solid secondary tumors (4) occurred in regions that had received radiation. Of the 6 high-grade gliomas, 5 occurred >5 years postdiagnosis. The estimated cumulative 10-year incidence rate of secondary malignancies was 4.2% (1.9%–6.5%). Few patients with medulloblastoma will relapse ≥5 years postdiagnosis; relapse will occur predominantly at the primary tumor site. Patients are at risk for development of secondary tumors, many of which are malignant gliomas. This may become an increasing issue as more children survive.
doi:10.1093/neuonc/nos267
PMCID: PMC3534419  PMID: 23099653
chemotherapy; medulloblastoma; radiotherapy; secondary tumors
4.  Optimizing biologically targeted clinical trials for neurofibromatosis 
Introduction
The neurofibromatoses (neurofibromatosis type 1, NF1 and neurofibromatosis type 2, NF2) comprise the most common inherited conditions in which affected children and adults develop tumors of the central and peripheral nervous system. In this review, the authors discuss how the establishment of the Neurofibromatosis Clinical Trials Consortium (NFCTC) has positively impacted on the design and execution of treatment studies for individuals with NF1 and NF2.
Areas covered
Using an extensive PUBMED search in collaboration with select NFCTC members expert in distinct NF topics, the authors discuss the clinical features of NF1 and NF2, the molecular biology of the NF1 and NF2 genes, the development and application of clinically relevant Nf1 and Nf2 genetically engineered mouse models and the formation of the NFCTC to enable efficient clinical trial design and execution.
Expert opinion
The NFCTC has resulted in a more seamless integration of mouse preclinical and human clinical trials efforts. Leveraging emerging enabling resources, current research is focused on identifying subtypes of tumors in NF1 and NF2 to deliver the most active compounds to the patients most likely to respond to the targeted therapy.
doi:10.1517/13543784.2013.772979
PMCID: PMC4009992  PMID: 23425047
clinical trials; mouse models; NF1; NF2; preclinical
5.  Tumors of the Central Nervous System: Clinical Aspects, Molecular Mechanisms, Unanswered Questions, and Future Research Directions 
Journal of child neurology  2008;23(10):1103-1121.
Central nervous system tumors are the most common solid tumors in children. Many histological subtypes and biological variants exist. The 2007 Neurobiology of Disease in Children Symposium, held in conjunction with the 36th annual meeting of the Child Neurology Society, aimed to define current knowledge in the field and to develop specific aims for future clinical, translational, and fundamental science. Because of advances in structural and metabolic imaging, surgical technique, and combination therapies, the life expectancy of children with some of the most common tumors, such as cerebellar astrocytomas and medulloblastomas, has improved. Other common tumor types, including diffuse pontine gliomas and malignant embryonal tumors, still have a dismal prognosis. As novel therapies are identified for pediatric central nervous system tumors, long-term survival may be associated with considerable disability. A cooperative effort is crucial to early diagnosis and to translating basic research findings into safe, effective new treatments.
doi:10.1177/0883073808321767
PMCID: PMC3674821  PMID: 18952577
6.  Randomized Study of Two Chemotherapy Regimens for Treatment of Low-Grade Glioma in Young Children: A Report From the Children's Oncology Group 
Journal of Clinical Oncology  2012;30(21):2641-2647.
Purpose
Surgery is curative therapy for pediatric low-grade gliomas (LGGs) in areas of the brain amenable to complete resection. However, LGGs located in areas where complete resection is not possible can threaten both function and life. The purpose of this study was to compare two chemotherapy regimens for LGGs in children younger than age 10 years for whom radiotherapy was felt by the practitioner to pose a high risk of neurodevelopmental injury.
Patients and Methods
Previously untreated children younger than age 10 years with progressive or residual LGGs were eligible. Children were randomly assigned to receive carboplatin and vincristine (CV) or thioguanine, procarbazine, lomustine, and vincristine (TPCV). Children with neurofibromatosis are reported separately.
Results
Of 274 randomly assigned patients who met eligibility requirements, 137 received CV and 137 received TPCV. The 5-year event-free survival (EFS) and overall survival (OS) rates for all eligible patients were 45% ± 3.2% and 86% ± 2.2%, respectively. The 5-year EFS rates were 39% ± 4% for CV and 52% ± 5% for TPCV (stratified log-rank test P = .10; cure model analysis P = .007). On multivariate analysis, factors independently predictive of worse EFS and OS were younger age and tumor size greater than 3 cm2. Tumor location in the thalamus was also associated with poor OS.
Conclusion
The difference in EFS between the regimens did not reach significance on the basis of the stratified log-rank test. The 5-year EFS was higher for TPCV on the basis of the cure model analysis. Differences in toxicity may influence physician choice of regimens.
doi:10.1200/JCO.2011.36.6054
PMCID: PMC3413276  PMID: 22665535
7.  Medulloblastoma Down Under 2013: a report from the third annual meeting of the International Medulloblastoma Working Group 
Acta Neuropathologica  2013;127:189-201.
Medulloblastoma is curable in approximately 70 % of patients. Over the past decade, progress in improving survival using conventional therapies has stalled, resulting in reduced quality of life due to treatment-related side effects, which are a major concern in survivors. The vast amount of genomic and molecular data generated over the last 5–10 years encourages optimism that improved risk stratification and new molecular targets will improve outcomes. It is now clear that medulloblastoma is not a single-disease entity, but instead consists of at least four distinct molecular subgroups: WNT/Wingless, Sonic Hedgehog, Group 3, and Group 4. The Medulloblastoma Down Under 2013 meeting, which convened at Bunker Bay, Australia, brought together 50 leading clinicians and scientists. The 2-day agenda included focused sessions on pathology and molecular stratification, genomics and mouse models, high-throughput drug screening, and clinical trial design. The meeting established a global action plan to translate novel biologic insights and drug targeting into treatment regimens to improve outcomes. A consensus was reached in several key areas, with the most important being that a novel classification scheme for medulloblastoma based on the four molecular subgroups, as well as histopathologic features, should be presented for consideration in the upcoming fifth edition of the World Health Organization’s classification of tumours of the central nervous system. Three other notable areas of agreement were as follows: (1) to establish a central repository of annotated mouse models that are readily accessible and freely available to the international research community; (2) to institute common eligibility criteria between the Children’s Oncology Group and the International Society of Paediatric Oncology Europe and initiate joint or parallel clinical trials; (3) to share preliminary high-throughput screening data across discovery labs to hasten the development of novel therapeutics. Medulloblastoma Down Under 2013 was an effective forum for meaningful discussion, which resulted in enhancing international collaborative clinical and translational research of this rare disease. This template could be applied to other fields to devise global action plans addressing all aspects of a disease, from improved disease classification, treatment stratification, and drug targeting to superior treatment regimens to be assessed in cooperative international clinical trials.
doi:10.1007/s00401-013-1213-7
PMCID: PMC3895219  PMID: 24264598
8.  Lack of efficacy of bevacizumab + irinotecan in cases of pediatric recurrent ependymoma—a Pediatric Brain Tumor Consortium study 
Neuro-Oncology  2012;14(11):1404-1412.
A phase II study of bevacizumab (BVZ) plus irinotecan (CPT-11) was conducted in cases of pediatric recurrent ependymoma (EPN) to estimate sustained objective response rate and progression-free survival (PFS). Eligible patients received 2 doses of single-agent BVZ intravenously (10 mg/kg) 2 weeks apart and then BVZ + CPT-11 every 2 weeks until progressive disease, unacceptable toxicity, or a maximum of 2 years of therapy. Correlative studies included diffusion-weighted and T1 dynamic contrast enhanced permeability imaging and tumor immunohistochemistry for vascular endothelial growth factor (VEGF)–A and –B, hypoxia inducible factor–2α, VEGF receptor (R)–2, and carbonic anhydrase (CA)–9. Thirteen evaluable patients received a median of 3 courses (range, 2–12) of BVZ + CPT-11. No sustained response was observed in any patient. Median time to progression in 10 patients was 2.2 months (range, 1.9–6.3). Two patients had stable disease for 10 months and 12 months, respectively. Six-month PFS was 25.7% (SE = 11.1%). Grades I–III toxicities related to BVZ treatment included fatigue in 4 patients, systemic hypertension in 2, epistaxis in 1, headache in 1, and avascular necrosis of bone in 1. Although there was a decrease in the mean diffusion ratio following 2 doses of BVZ, it did not correlate with PFS. BVZ + CPT-11 was well tolerated but had minimal efficacy in cases of recurrent EPN.
doi:10.1093/neuonc/nos213
PMCID: PMC3480265  PMID: 23019233
bevacizumab; CPT-11; efficacy; ependymoma; recurrent
9.  Phase I Trial of MK-0752 in Children With Refractory CNS Malignancies: A Pediatric Brain Tumor Consortium Study 
Journal of Clinical Oncology  2011;29(26):3529-3534.
Purpose
To estimate the maximum-tolerated dose (MTD), describe dose-limiting toxicities (DLTs), and characterize pharmacokinetic properties of MK-0752, a gamma secretase inhibitor, in children with refractory or recurrent CNS malignancies.
Patients and Methods
MK-0752 was administered once daily for 3 consecutive days of every 7 days at escalating dosages starting at 200 mg/m2. The modified continual reassessment method was used to estimate the MTD. A course was 28 days in duration. Pharmacokinetic analysis was performed during the first course. Expression of NOTCH and hairy enhancer of split (HES) proteins was assessed in peripheral-blood mononuclear cells (PBMCs) before and following treatment with MK-0752.
Results
Twenty-three eligible patients were enrolled: 10 males (median age, 8.1 years; range, 2.6 to 17.7 years) with diagnoses of brainstem glioma (n = 6), ependymoma (n = 8), medulloblastoma/primitive neuroectodermal tumor (n = 4), glioblastoma multiforme (n = 2), atypical teratoid/rhabdoid tumor (n = 1), malignant glioma (n = 1), and choroid plexus carcinoma, (n = 1). Seventeen patients were fully evaluable for toxicity. No DLTs occurred in the three patients enrolled at 200 mg/m2/dose. At 260 mg/m2/dose, DLTs occurred in two of six patients, both of whom experienced grade 3 ALT and AST. There were no grade 4 toxicities; non–dose-limiting grade 3 toxicities included hypokalemia and lymphopenia. Population pharmacokinetic values (% coefficient of variation) for MK-0752 were apparent oral clearance, 0.444 (38%) L/h/m2; apparent volume of distribution, 7.36 (24%) L/m2; and ka, 0.358 (99%) hr−1.
Conclusion
MK-0752 is well-tolerated in children with recurrent CNS malignancies. The recommended phase II dose using the 3 days on followed by 4 days off schedule is 260 mg/m2/dose once daily.
doi:10.1200/JCO.2011.35.7806
PMCID: PMC3179253  PMID: 21825264
10.  Antioxidant enzyme polymorphisms and neuropsychological outcomes in medulloblastoma survivors: a report from the Childhood Cancer Survivor Study 
Neuro-Oncology  2012;14(8):1018-1025.
Psychological or neurocognitive impairment is often seen in medulloblastoma survivors after craniospinal radiation; however, significant variability in outcomes exists. This study investigated the role of antioxidant enzyme polymorphisms in moderating this outcome and hypothesized that patients who had polymorphisms associated with lower antioxidant enzyme function would have a higher occurrence of impairment. From the Childhood Cancer Survivor Study (CCSS) cohort, 109 medulloblastoma survivors and 143 siblings were identified who completed the CCSS Neurocognitive Questionnaire (NCQ) and the Brief Symptom Inventory-18 (BSI-18) and who provided buccal DNA samples. Real-time polymerase chain reaction (PCR) allelic discrimination was used for SOD2 (rs4880), GPX1 (rs1050450), and GSTP1 (rs1695 and rs1138272) genotyping and PCR for GSTM1 and GSTT1 gene deletions. Outcomes on NCQ and BSI-18 subscale scores were examined in association with genotypes and clinical factors, including age at diagnosis, sex, and radiation dose, using univariate and multivariate analysis of variance. Patients <7 years of age at diagnosis displayed more problems with task efficiency (P < .001) and fewer problems with somatic complaints (P = .004) than did patients ≥7 years of age. Female patients reported more organization problems than did male patients (P = .02). Patients with homozygous GSTM1 gene deletion reported higher anxiety (mean null genotype = 47.3 ± 9.2, non-null = 43.9 ± 7.8; P = .04), more depression (null = 51.0 ± 9.8, non-null = 47.0 ± 9.4; P = .03), and more global distress (null = 50.2 ± 9.7, non-null = 45.2 ± 9.9; P = .01). All associations for the GSTM1 polymorphism remained statistically significant in a multivariate model controlling for age, sex, and radiation dose. Homozygous GSTM1 gene deletion was consistently associated with greater psychological distress in medulloblastoma survivors across multiple domains, suggesting that this genotype may predispose patients for increased emotional late effects.
doi:10.1093/neuonc/nos123
PMCID: PMC3408256  PMID: 22661588
Childhood Cancer Survivor Study; glutathione S-transferase polymorphisms; medulloblastoma; neuropsychological impairment; radiation therapy
11.  Childhood Brain Tumors: Accomplishments and Ongoing Challenges 
Journal of child neurology  2008;23(10):1122-1127.
The management of childhood brain tumors, which consist of many different histological subtypes, continues to be a challenge. Outcome, measured not only by survival rates but also by the effects of disease and therapy on quality of life, has improved over the past two decades for some tumor types, most notably medulloblastomas. For others, however, there has been little progress, and quality of life for long-term survivors remains suboptimal. Because of advances in our understanding of the biology underlying childhood brain tumors, treatments may change dramatically in the years ahead. Accordingly, survival rates may improve and long-term sequelae lessen.
doi:10.1177/0883073808320758
PMCID: PMC3674838  PMID: 18952578
12.  Visual outcomes in children with neurofibromatosis type 1–associated optic pathway glioma following chemotherapy: a multicenter retrospective analysis 
Neuro-Oncology  2012;14(6):790-797.
Optic pathway gliomas (OPGs) occur in 15%–20% of children with neurofibromatosis type 1 (NF1); up to half become symptomatic. There is little information regarding ophthalmologic outcomes after chemotherapy. A retrospective multicenter study was undertaken to evaluate visual outcomes following chemotherapy for NF1-associated OPG, to identify risks for visual loss, and to ascertain indications for treatment. Subjects included children undergoing initial treatment for OPGs with chemotherapy between January 1997 and December 2007. Of 115 subjects, visual acuity (VA) decline and tumor progression were the primary reasons to initiate treatment, although there were significant differences in the pattern of indications cited among the institutions. Eighty-eight subjects and 168 eyes were evaluable for VA outcome. At completion of chemotherapy, VA improved (32% of subjects), remained stable (40%), or declined (28%). Tumor location was the most consistent prognostic factor for poor VA outcome. There was poor correlation between radiographic and VA outcomes. Although visual outcomes for NF1-associated OPG are not optimal, approximately one-third of children regain some vision with treatment. Since radiographic outcomes do not predict visual outcomes, their use as the primary measure of treatment success is in question. The lack of consensus regarding the indications for treatment underlines the need for better standardization of care. Future clinical trials for OPG require standardized visual assessment methods and clear definitions of visual outcomes.
doi:10.1093/neuonc/nos076
PMCID: PMC3367846  PMID: 22474213
neurofibromatosis; optic glioma; outcomes; visual acuity
13.  Biologically Targeted Therapeutics in Pediatric Brain Tumors 
Pediatric neurology  2012;46(4):203-211.
Pediatric brain tumors are often difficult to cure and involve significant morbidity when treated with traditional treatment modalities, including neurosurgery, conventional chemotherapy, and radiotherapy. During the past two decades, a clearer understanding of tumorigenesis, molecular growth pathways, and immune mechanisms in the pathogenesis of cancer has opened up promising avenues for therapy. Pediatric clinical trials with novel biologic agents are underway to treat various pediatric brain tumors, including high and low grade gliomas and embryonal tumors. As the therapeutic potential of these agents undergoes evaluation, their toxicity profiles are also becoming better understood. These agents have potentially better central nervous system penetration and lower toxicity profiles compared with conventional chemotherapy. In infants and younger children, biologic agents may prove to be of equal or greater efficacy compared with traditional chemotherapy and radiation therapy, and may reduce the deleterious side effects of traditional therapeutics on the developing brain. Molecular pathways implicated in pediatric brain tumors, agents that target these pathways, and current clinical trials are reviewed. Associated neurologic toxicities will be discussed subsequently. Considerable work is needed to establish the efficacy of these agents alone and in combination, but pediatric neurologists should be aware of these agents and their rationale.
doi:10.1016/j.pediatrneurol.2012.02.005
PMCID: PMC3654250  PMID: 22490764
14.  Insights into pediatric diffuse intrinsic pontine glioma through proteomic analysis of cerebrospinal fluid 
Neuro-Oncology  2012;14(5):547-560.
Diffuse intrinsic pontine glioma (DIPG) is a leading cause of brain tumor–related death in children. DIPG is not surgically resectable, resulting in a paucity of tissue available for molecular studies. As such, tumor biology is poorly understood, and, currently, there are no effective treatments. In the absence of frozen tumor specimens, body fluids—such as cerebrospinal fluid (CSF), serum, and urine—can serve as more readily accessible vehicles for detecting tumor-secreted proteins. We analyzed a total of 76 specimens, including CSF, serum, urine, and normal and tumor brainstem tissue. Protein profiling of CSF from patients with DIPG was generated by mass spectrometry using an LTQ-Orbitrap-XL and database search using the Sequest algorithm. Quantitative and statistical analyses were performed with ProteoIQ and Partek Genomics Suite. A total of 528 unique proteins were identified, 71% of which are known secreted proteins. CSF proteomic analysis revealed selective upregulation of Cyclophillin A (CypA) and dimethylarginase 1 (DDAH1) in DIPG (n = 10), compared with controls (n = 4). Protein expression was further validated with Western blot analysis and immunohistochemical assays using CSF, brain tissue, serum, and urine from DIPG and control specimens. Immunohistochemical staining showed selective upregulation of secreted but not cytosolic CypA and DDAH1 in patients with DIPG. In this study, we present the first comprehensive protein profile of CSF specimens from patients with DIPG to demonstrate selective expression of tumor proteins potentially involved in brainstem gliomagenesis. Detection of secreted CypA and DDAH1 in serum and urine has potential clinical application, with implications for assessing treatment response and detecting tumor recurrence in patients with DIPG.
doi:10.1093/neuonc/nos067
PMCID: PMC3337313  PMID: 22492959
brainstem glioma; CSF; CypA; DDAH1; DIPG
15.  Lovastatin regulates brain spontaneous low-frequency brain activity in Neurofibromatosis type 1 
Neuroscience Letters  2012;515(1):28-33.
In the Neurofibromatosis type 1 (NF1) mouse model, lovastatin, used clinically for hypercholesterolemia, improves cognitive dysfunction. While such impairment has been studied in NF1, the neural substrates remain unclear. The aim of this imaging add-on to a phase-1 open-label trial was to examine the effect of lovastatin on Default Network (DN) resting state functional connectivity (RSFC). Seven children with NF1 (aged 11.9±2.2; 1 female) were treated with lovastatin once daily for 12 weeks. A 7-minute 3-Tesla echo-planar-imaging scan was collected one day before beginning treatment (off-drug) and the last day of treatment (on-drug) while performing a Flanker task. After regressing-out task-associated variance, we used the residual time series as “continuous resting-state data” for RSFC analyses using 11 DN regions of interest. For qualitative comparisons, we included a group of 19 typically developing children (TDC) collected elsewhere. In the on-drug condition, lovastatin increased long-range positive RSFC within DN core regions (i.e., anterior medial prefrontal cortex and posterior cingulate cortex, PCC). In addition, lovastatin produced less diffuse local RSFC in the dorsomedial prefrontal cortex and PCC. The pattern of RSFC observed in the NF1 participants when on-drug closely resembled the RSFC patterns exhibited by the TDC. Lovastatin administration in this open trial regulated anterior-posterior long-range and local RSFC within the DN. These preliminary results are consistent with a role for lovastatin in normalization of developmental processes and with apparent benefits in a mouse NF1 model.
doi:10.1016/j.neulet.2012.03.009
PMCID: PMC3363969  PMID: 22433254
Neurofibromatosis type 1; lovastatin; resting-state fMRI; Default Network; children
16.  Neurotoxicity of Biologically Targeted Agents in Pediatric Cancer Trials 
Pediatric neurology  2012;46(4):212-221.
Biologically targeted agents offer the promise of delivering specific anticancer effects while limiting damage to healthy tissue, including the central and peripheral nervous systems. During the past 5-10 years, these agents were examined in preclinical and adult clinical trials, and are used with increasing frequency in children with cancer. This review evaluates current knowledge about neurotoxicity from biologically targeted anticancer agents, particularly those in pediatric clinical trials. For each drug, neurotoxicity data are reviewed in adult (particularly studies of brain tumors) and pediatric studies when available. Overall, these agents are well tolerated, with few serious neurotoxic effects. Data from younger patients are limited, and more neurotoxicity may occur in the pediatric population because these agents target pathways that control not only tumorigenesis but also neural maturation. Further investigation is needed into long-term neurologic effects, particularly in children.
doi:10.1016/j.pediatrneurol.2012.02.006
PMCID: PMC3626408  PMID: 22490765
17.  A Phase II Study of O6-Benzylguanine and Temozolomide in Pediatric Patients with Recurrent or Progressive High Grade Gliomas and Brainstem Gliomas: A Pediatric Brain Tumor Consortium Study 
Journal of neuro-oncology  2011;106(3):643-649.
Purpose
To estimate the sustained (≥8 weeks) objective response rate in pediatric patients with recurrent or progressive high-grade gliomas (HGG, Stratum A) or brainstem gliomas (BSG, Stratum B) treated with the combination of O6-benzylguanine (O6BG) and temozolomide® (TMZ).
Patients and Methods
Patients received O6BG 120 mg/m2/d IV followed by TMZ 75 mg/m2/d orally daily for 5 consecutive days of each 28-day course. The target objective response rate to consider the combination active was 17%. A two-stage design was employed.
Results
Forty-three patients were enrolled; 41 were evaluable for response, including 25 patients with HGG and 16 patients with BSG. The combination of O6BG and TMZ was tolerable, and the primary toxicities were myelosuppression and gastrointestinal symptoms. One sustained (≥8 weeks) partial response was observed in the HGG cohort; no sustained objective responses were observed in the BSG cohort. Long-term (≥6 courses) stable disease (SD) was observed in 4 patients in Stratum A and 1 patient in Stratum B. Of the 5 patients with objective response or long-term SD, 3 underwent central review with 2 reclassified as low-grade gliomas.
Conclusions
The combination of O6BG and TMZ did not achieve the target response rate for activity in pediatric patients with recurrent or progressive HGG and BSG.
doi:10.1007/s11060-011-0709-z
PMCID: PMC3518022  PMID: 21968943
glioma; pediatric; resistance; alkylating agent; brainstem glioma; AGT; MGMT
18.  Phase II trial of tipifarnib and radiation in children with newly diagnosed diffuse intrinsic pontine gliomas 
Neuro-Oncology  2011;13(3):298-306.
We performed a phase II study to assess the efficacy and toxicity of tipifarnib, a farnesyltransferase inhibitor, administered with radiation therapy (RT) in children with newly diagnosed diffuse intrinsic pontine gliomas. Children 3-21 years old with pontine gliomas (BSGs) were treated with concurrent tipifarnib and RT, followed by adjuvant tipifarnib. Tipifarnib was taken orally twice daily (125 mg/m2/dose) during RT; after RT, it was taken at 200 mg/m2 twice daily for 21 days, in 28-day cycles. Initial and follow-up neuroimaging was centrally reviewed. Forty eligible patients (median age, 5.5 years; range, 3.3–16.5 years) had a median progression-free survival of 6.8 months (range, 0.2-18.6 months) and median overall survival of 8.3 months (range, 0.2-18.6 months). Kaplan–Meier estimates (± standard error) of 1-year progression-free and overall survival were 12.9% ±4.9% and 34.3% ±7.4%, respectively. A single patient remained on tipifarnib without progression at the completion of the study, two years after initiation of treatment. Seven patients were without disease progression for at least six months, three of whom remained controlled for more than a year. The most frequent toxicity was grade 3 lymphopenia. We documented a single instance of “pseudoprogression” by neuroimaging review. We found no discordance among 3 approaches to defining disease progression: as interpreted by treating institutions (based on clinical status and/or imaging) and by central review (using bi-dimensional tumor “area” versus volumetric measurements). For children with diffuse BSGs, tipifarnib administered with irradiation offered no clinical advantage over historical controls. Biopsies and molecular analyses of pediatric BSGs are vital for identification of new agents and for rational use of targeted agents.
doi:10.1093/neuonc/noq202
PMCID: PMC3064607  PMID: 21339191
diffuse intrinsic pontine glioma; farnesyltransferase inhibitors; pediatric
19.  Radiation therapy quality in CCG/POG intergroup 9961: implications for craniospinal irradiation and the posterior fossa boost in future medulloblastoma trials 
Frontiers in Oncology  2012;2:185.
Purpose: Associations of radiation therapy (RT) deviations and outcomes in medulloblastoma have not been defined well, particularly in the era of reduced-dose craniospinal irradiation and chemotherapy. The aim of this study is to evaluate the quality of RT on Children’s Cancer Group/Pediatric Oncology Group 9961 and analyze associations of RT deviations with outcome. Materials and Methods: Major volume deviations were assessed based on the distance from specified anatomical region to field edge. We investigated associations of RT deviations with progression-free survival (PFS), overall survival (OS), and explored associations with demographics and clinical variables. Results: Of the 308 patients who were evaluable for volume deviations, 101 patients (33%) did not have any. Of the remaining 207 patients, 50% had only minor deviations, 29% had only major deviations, and 21% had both minor and major deviations. Of the patients with major deviations, 73% had a single major deviation. The most common major deviation was in the cribriform plate region, followed by the posterior fossa (PF); PF deviations resulted from treating less than whole PF. There were no significant differences in PFS or OS between patients with deviations and those without. There was no evidence of associations of deviations with patient age. Conclusions: Approximately one-third of patients had major volume deviations. There was no evidence of a significant association between these and outcome. This lack of correlation likely reflects the current high quality of RT delivered in Children’s Oncology Group institutions, our strict definition of volume deviations, and the relatively few instances of multiple major deviations in individual patients. In is noteworthy that the types of PF volume deviations observed in this study were not adversely associated with outcome. As we move forward, quality assurance will continue to play an important role to ensure that deviations on study do not influence study outcome.
doi:10.3389/fonc.2012.00185
PMCID: PMC3540930  PMID: 23316474
medulloblastoma; radiation therapy; quality assurance; craniospinal; posterior fossa
20.  A Phase I and Biology Study of Gefitinib and Radiation in Children with Newly Diagnosed Brain Stem Gliomas or Supratentorial Malignant Gliomas 
Purpose
To estimate the maximum tolerated dose (MTD); study the pharmacology of escalating doses of gefitinib combined with radiation therapy in patients ≤21 years with newly diagnosed intrinsic brainstem gliomas (BSG) and incompletely resected supratentorial malignant gliomas (STMG); and to investigate epidermal growth factor receptor (EGFR) amplification and expression in STMG.
Patients and methods
Three strata were identified: Stratum 1A - BSG; Stratum IB - incompletely resected STMG not receiving enzyme inducing anti-convulsant drugs (EIACD); and Stratum II - incompletely resected STMG receiving EIACD. Dose escalation using a modified 3 + 3 cohort design was performed in strata IA & II. The initial gefitinib dosage was 100mg/m2/day commencing with radiation therapy and the dose-finding period extended until 2 weeks post-radiation. Pharmacokinetics (PK) and biology studies were performed in consenting patients.
Results
Of 23 eligible patients, 20 were evaluable for dose-finding. MTDs for strata IA and II were not established as accrual was halted due to four patients experiencing symptomatic intratumoral hemorrhage (ITH); 2 during and 2 post dose-finding. ITH was observed in 0 of 11 patients treated at 100mg/m2/day, 1 of 10 at 250mg/m2/day, and 3 of 12 at 375mg/m2/day. Subsequently a second patient at 250mg/m2/day experienced ITH. PK analysis showed the median gefitinib systemic exposure increased with dosage (p=0.04). EGFR was overexpressed in 5 of 11 STMG and amplified in 4 (36%) samples.
Conclusion
This trial provides clear evidence of EGFR amplification in a significant proportion of paediatric STMG and 250mg/m2/day was selected for the Phase II trial.
doi:10.1016/j.ejca.2010.07.005
PMCID: PMC2988095  PMID: 20708924
epidermal growth factor receptor; gefitinib; radiotherapy; brain stem neoplasms; supratentorial neoplasms; glioma
21.  Region-specific radiotherapy and neuropsychological outcomes in adult survivors of childhood CNS malignancies 
Neuro-Oncology  2010;12(11):1173-1186.
Childhood cancer survivors exposed to CNS irradiation are at increased risk for neurocognitive deficits; however, limited data exist linking outcomes with region-specific exposure to CNS irradiation. We report associations between region-specific radiation dose and self-reported neurocognitive and health-related quality of life (HRQOL) outcomes in 818 adult survivors of childhood central nervous system (CNS) malignancies from the Childhood Cancer Survivor Study. Survivors were compared with a sibling group and national normative samples to calculate standardized scores. Cumulative radiation dose was calculated for 4 specific brain regions. Logistic regression was used to estimate the association between radiation dose to specific brain regions and outcome measures of functional impairment adjusted for clinical and demographic factors, including sex and age at diagnosis. High radiation dose levels to temporal regions were associated with a higher risk for memory impairment (radiation doses ≥30 to <50 Gy: OR, 1.95; 95% CI, 1.01–3.78; dose ≥50 Gy: OR, 2.34; 95% CI, 1.25–4.39) compared with those with no radiation exposure. No such association was seen with radiation exposure to other regions. Exposure to temporal regions was associated with more social and general health problems, whereas exposure to frontal regions was associated with general health problems and physical performance limitations. Adult survivors of childhood CNS malignancies report higher rates of neuropsychological and HRQOL outcomes, which vary as a function of dose to specific neuroanatomical regions. Survivors with a history of radiation exposure to temporal brain regions are at increased risk for impairment in memory and social functioning.
doi:10.1093/neuonc/noq104
PMCID: PMC3098024  PMID: 20716593
CNS malignancies; Childhood Cancer Survivor Study (CCSS); health-related quality of life; neuropsychological functioning; radiation therapy
22.  Phase I Trial of Lapatinib in Children With Refractory CNS Malignancies: A Pediatric Brain Tumor Consortium Study 
Journal of Clinical Oncology  2010;28(27):4221-4227.
Purpose
To estimate the maximum-tolerated dose, dose-limiting toxicities (DLTs), and pharmacokinetic properties of lapatinib, a selective epidermal growth factor receptor (EGFR) and ERBB2 inhibitor, in children with refractory or recurrent CNS malignancies.
Patients and Methods
Lapatinib was administered orally twice daily at escalating doses starting at 300 mg/m2 to patients who were not (stratum I) or were (stratum II) receiving steroids. Pharmacokinetic studies were performed during the first two courses. Expression of the four ERBB receptors and downstream signaling elements in tumor tissue was evaluated by immunohistochemistry.
Results
Fifty-nine patients were enrolled (stratum I, n = 32; stratum II, n = 27). Of 29 patients evaluable for toxicity in stratum I, one experienced a DLT (diarrhea) at 520 mg/m2 twice daily, and all three receiving 1,150 mg/m2 twice daily experienced DLTs (one each of rash, diarrhea, and fatigue). Two of 21 patients evaluable for toxicity in stratum II experienced DLTs of rash at 900 mg/m2 twice daily. Lapatinib dosage was related linearly to area under the [concentration-time] curve from start time to 12 hours later (AUC0-12) and dose-normalized maximum serum concentration and AUC values for patients in stratum II were both significantly higher (P = .001) than those for patients in stratum I. Frequent, high-level expression of activated (phosphorylated) EGFR and ERBB2 receptors and downstream signal intermediates were observed in tumors, particularly in ependymomas that displayed prolonged stable disease on lapatinib therapy.
Conclusion
Lapatinib is well tolerated in children with recurrent CNS malignancies, with rash, diarrhea, and fatigue identified as DLTs. The recommended phase II dose, regardless of steroid use, is 900 mg/m2 twice daily.
doi:10.1200/JCO.2010.28.4687
PMCID: PMC2953974  PMID: 20713864
23.  Lack of Efficacy of Bevacizumab Plus Irinotecan in Children With Recurrent Malignant Glioma and Diffuse Brainstem Glioma: A Pediatric Brain Tumor Consortium Study 
Journal of Clinical Oncology  2010;28(18):3069-3075.
Purpose
A phase II study of bevacizumab (BVZ) plus irinotecan (CPT-11) was conducted in children with recurrent malignant glioma (MG) and intrinsic brainstem glioma (BSG).
Patients and Methods
Eligible patients received two doses of BVZ intravenously (10 mg/kg) 2 weeks apart and then BVZ plus CPT-11 every 2 weeks until progressive disease, unacceptable toxicity, or a maximum of 2 years of therapy. Correlative studies included diffusion weighted and T1 dynamic contrast–enhanced permeability imaging, BVZ pharmacokinetics, and estimation of vascular endothelial growth factor receptor 2 (VEGFR-2) phosphorylation in peripheral blood mononuclear cells (PBMC) after single-agent BVZ.
Results
Thirty-one evaluable patients received a median of two courses of BVZ plus CPT-11 (range, 1 to 19). No sustained responses were observed in either stratum. Median time to progression for all 34 eligible patients enrolled was 127 days for MG and 71 days for BSG. Progression-free survival rates at 6 months were 41.8% and 9.7% for MG and BSG, respectively. Toxicities related to BVZ included grade 1 to 3 fatigue in seven patients, grade 1 to 2 hypertension in seven patients, grade 1 CNS hemorrhage in four patients, and grade 4 CNS ischemia in two patients. The mean diffusion ratio decreased after two doses of BVZ in patients with MG only. Vascular permeability parameters did not change significantly after therapy in either stratum. Inhibition of VEGFR-2 phosphorylation in PBMC was detected in eight of 11 patients after BVZ exposure.
Conclusion
BVZ plus CPT-11 was well-tolerated but had minimal efficacy in children with recurrent malignant glioma and brainstem glioma.
doi:10.1200/JCO.2009.26.8789
PMCID: PMC2903337  PMID: 20479404
24.  Late-Occurring Neurologic Sequelae in Adult Survivors of Childhood Acute Lymphoblastic Leukemia: A Report From the Childhood Cancer Survivor Study 
Journal of Clinical Oncology  2009;28(2):324-331.
Purpose
Children with acute lymphoblastic leukemia (ALL) are often cured, but the therapies they receive may be neurotoxic. Little is known about the incidence and severity of late-occurring neurologic sequelae in ALL survivors. Data were analyzed to determine the incidence of adverse long-term neurologic outcomes and treatment-related risk factors.
Patients and Methods
We analyzed adverse neurologic outcomes that occurred after diagnosis in 4,151 adult survivors of childhood ALL who participated in the Childhood Cancer Survivor Study (CCSS), a retrospective cohort of 5-year survivors of childhood cancer diagnosed between 1970 and 1986. A randomly selected cohort of the survivors' siblings served as a comparison group. Self-reported auditory-vestibular-visual sensory deficits, focal neurologic dysfunction, seizures, and serious headaches were assessed.
Results
The median age at outcome assessment was 20.2 years for survivors. The median follow-up time to death or last survey since ALL diagnosis was 14.1 years. Of the survivors, 64.5% received cranial radiation and 94% received intrathecal chemotherapy. Compared with the sibling cohort, survivors were at elevated risk for late-onset auditory-vestibular-visual sensory deficits (rate ratio [RR], 1.8; 95% CI, 1.5 to 2.2), coordination problems (RR, 4.1; 95% CI, 3.1 to 5.3), motor problems (RR, 5.0; 95% CI, 3.8 to 6.7), seizures (RR, 4.6; 95% CI, 3.4 to 6.2), and headaches (RR, 1.6; 95% CI, 1.4 to 1.7). In multivariable analysis, relapse was the most influential factor that increased risk of late neurologic complications.
Conclusion
Children treated with regimens that include cranial radiation for ALL and those who suffer a relapse are at increased risk for late-onset neurologic sequelae.
doi:10.1200/JCO.2009.22.5060
PMCID: PMC2815720  PMID: 19917844
25.  Ocular Late Effects in Childhood and Adolescent Cancer Survivors: A Report from the Childhood Cancer Survivor Studya 
Pediatric blood & cancer  2010;54(1):103-109.
Introduction
Approximately 80% of children currently survive 5 years following diagnosis of their cancer. Studies based on limited data have implicated certain cancer therapies in the development of ocular sequelae in these survivors.
Procedure
The Childhood Cancer Survivor Study (CCSS) is a retrospective cohort study investigating health outcomes of 5+ year survivors diagnosed and treated between 1970 and 1986 compared to a sibling cohort. The baseline questionnaire included questions about the first occurrence of 6 ocular conditions. Relative risks (RR) and 95% confidence intervals (CI) were calculated from responses of 14,362 survivors and 3,901 siblings.
Results
Five or more years from the diagnosis, survivors were at increased risk of cataracts (RR:10.8; 95% CI: 6.2–18.9), glaucoma (RR: 2.5; 95% CI: 1.1–5.7), legal blindness (RR: 2.6; 95% CI: 1.7–4.0), double vision (RR:4.1; 95% CI: 2.7–6.1), and dry eyes (RR: 1.9; 95% CI: 1.6–2.4), when compared to siblings. Dose of radiation to the eye was significantly associated with risk of cataracts, legal blindness, double vision, and dry eyes, in a dose-dependent fashion. Risk of cataracts were also associated with radiation 3000+ cGy to the posterior fossa (RR: 8.4; 95% CI: 5.0–14.3), temporal lobe (RR: 9.4; 95% CI: 5.6–15.6), and exposure to prednisone (RR:2.3; 95% CI:.1.6–3.4)
Conclusions
Childhood cancer survivors are at risk of developing late occurring ocular complications, with exposure to glucocorticoids and cranial radiation being important determinants of increased risk. Long-term follow-up is needed to evaluate potential progression of ocular deficits and impact on quality of life.
doi:10.1002/pbc.22277
PMCID: PMC2783513  PMID: 19774634
late effects of cancer therapy; radiation therapy; chemotherapy

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