A B S T R A C T PurposeLong-term survival for children with diffuse intrinsic pontine glioma (DIPG) is less than 10%, and new therapeutic targets are urgently required. We evaluated a large cohort of DIPGs to identify recurrent genomic abnormalities and gene expression signatures underlying DIPG.
Patients and MethodsSingle-nucleotide polymorphism arrays were used to compare the frequencies of genomic copy number abnormalities in 43 DIPGs and eight low-grade brainstem gliomas with data from adult and pediatric (non-DIPG) glioblastomas, and expression profiles were evaluated using gene expression arrays for 27 DIPGs, six low-grade brainstem gliomas, and 66 nonbrainstem low-grade gliomas.
ResultsFrequencies of specific large-scale and focal imbalances varied significantly between DIPGs and nonbrainstem pediatric glioblastomas. Focal amplifications of genes within the receptor tyrosine kinase-Ras-phosphoinositide 3-kinase signaling pathway were found in 47% of DIPGs, the most common of which involved PDGFRA and MET. Thirty percent of DIPGs contained focal amplifications of cell-cycle regulatory genes controlling retinoblastoma protein (RB) phosphorylation, and 21% had concurrent amplification of genes from both pathways. Some tumors showed heterogeneity in amplification patterns. DIPGs showed distinct gene expression signatures related to developmental processes compared with nonbrainstem pediatric high-grade gliomas, whereas expression signatures of low-grade brainstem and nonbrainstem gliomas were similar.
ConclusionDIPGs comprise a molecularly related but distinct subgroup of pediatric gliomas. Genomic studies suggest that targeted inhibition of receptor tyrosine kinases and RB regulatory proteins may be useful therapies for DIPG.
These intensive chemotherapy regimens proved less effective than irradiation containing regimens. Our results indicate that, at the present time, standard treatment for CNS GCT continues to include irradiation either alone or combined with chemotherapy for pure germinomas and with chemotherapy for those with MMGCT.
Central nervous system (CNS) tumors generally leave sequelae that may compromise speech, language, swallowing, hearing, and voice functions. This report describes the incidence of speech-language and hearing complaints and disorders in children and adolescents with CNS tumor under treatment at one of the most important Brazilian reference center for pediatric cancer. One-hundred ninety patients were examined for speech-pathology screening and analysis: forty-two percent presented with complaints and symptoms. From the remaining patients, 68% presented clinical symptoms and 32% were actually free from any speech-language and hearing-related symptoms. The high incidence of complaints and symptoms indicate that these patients might benefit from specific rehabilitation interventions.
The management of progressive unresectable low-grade glioma remains controversial. Treatment options have included radiotherapy, and more recently chemotherapy, usually following an initial period of observation. Within this context, we evaluated vinorelbine, a semi-synthetic vinca alkaloid that has shown evidence of activity against glioma. From July 2007 an institutional protocol with vinorelbine (30 mg/m(2) days 0, 8, 22) for a total of 18 cycles, has been conducted at IOP/GRAACC/UNIFESP for children with optic pathway glioma (OPG). The main objectives were clinical and radiological response, as well as toxicity profile. Twenty-three patients with progressive OPG with a mean age of 69 months (4-179) were enrolled. Three patients had a diagnosis of neurofibromatosis type 1. Twenty-two patients were assessable for response with an overall objective response rate of 63 %, with eight patients showing stable disease. The most important toxicity was hematologic (grade III/IV neutropenia) observed in four patients. Gastrointestinal toxicity (grade I/II vomiting) was observed in seven patients and only 1 patient showed grade I peripheral neuropathy. The median progression-free survival (PFS) was 33 months (6.9-69) with a 3 and 5 year PFS of 64 ± 19 and 37 ± 20 %, respectively, for an overall 3 and 5 year-survival of 95 ± 10 %. This study suggests that vinorelbine may be an interesting option for pediatric low-grade gliomas, showing low toxicity profile and providing a good quality of life for patients with such chronic disease.
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