Incidence of kiaa1549-braf fusion gene in Egyptian pediatric low grade glioma.

BACKGROUND: Low grade gliomas are the most common brain tumor in children. Tandem duplication involving the KIAA1549 and the BRAF kinase genes results in a gene fusion that has been recently characterized in a subset of low grade glioma While there is no clear evidence that the KIAA1549-BRAF gene fusion has an effect on prognosis, it is an attractive target for therapy development and as a diagnostic tool. METHODS: In the current study we examine the prevalence of KIAA1549-BRAF gene fusion in pediatric patients diagnosed with low grade glioma in the Egyptian population and its relationship to clinical and histological subtypes. Sixty patients between the ages of 1 to 18 years were analyzed for the presence of KIAA1549-BRAF fusion gene products using reverse transcription-PCR and sequencing. The clinicopathologic tumor characteristics were then analyzed in relation to the different fusion genes. RESULTS: KIAA1549-BRAF fusion genes were detected in 56.6% of patients. They were primarily associated with pilocytic astrocytoma (74.2%) and pilomyxoid astrocytoma (60%). Translocation 15-9 was the most common, representing (55.8%) of all positive samples followed by 16-9 (26.4%) and 16-11 (8.8%). Pilocytic astrocytomas presented primarily with 15-9 (32.2%), 16-9 (25.8%) and 16-11 (6.4%) while pilomyxoid astrocytomas presented with 15-9 (46.6%), 16-9 (6.6%) and 16-11 (6.6%) translocations. CONCLUSION: Gene fusion is found to be significantly increased in cerebellar pilocytic astrocytoma tumors. Furthermore, 15-9 was found to have a higher incidence among our cohort compared to previous studies. While most of the gene fusion positive pilomyxoid astrocytomas were 15-9, we find the association none significant.

Genomic analysis of diffuse pediatric low-grade gliomas identifies recurrent oncogenic truncating rearrangements in the transcription factor MYBL1.

Pediatric low-grade gliomas (PLGGs) are among the most common solid tumors in children but, apart from BRAF kinase mutations or duplications in specific subclasses, few genetic driver events are known. Diffuse PLGGs comprise a set of uncommon subtypes that exhibit invasive growth and are therefore especially challenging clinically. We performed high-resolution copy-number analysis on 44 formalin-fixed, paraffin-embedded diffuse PLGGs to identify recurrent alterations. Diffuse PLGGs exhibited fewer such alterations than adult low-grade gliomas, but we identified several significantly recurrent events. The most significant event, 8q13.1 gain, was observed in 28% of diffuse astrocytoma grade IIs and resulted in partial duplication of the transcription factor MYBL1 with truncation of its C-terminal negative-regulatory domain. A similar recurrent deletion-truncation breakpoint was identified in two angiocentric gliomas in the related gene v-myb avian myeloblastosis viral oncogene homolog (MYB) on 6q23.3. Whole-genome sequencing of a MYBL1-rearranged diffuse astrocytoma grade II demonstrated MYBL1 tandem duplication and few other events. Truncated MYBL1 transcripts identified in this tumor induced anchorage-independent growth in 3T3 cells and tumor formation in nude mice. Truncated transcripts were also expressed in two additional tumors with MYBL1 partial duplication. Our results define clinically relevant molecular subclasses of diffuse PLGGs and highlight a potential role for the MYB family in the biology of low-grade gliomas.

Spinal cord compression in childhood pediatric malignancies: multicenter egyptian study.

OBJECTIVES: To assess the magnitude of management delay of pediatric malignant spinal cord compression (MSCC). METHODS: Twenty-four patients with MSCC were recruited from 3 Egyptian pediatric oncology centers and assessed for MSCC clinical presentations, evaluation, and treatment response. RESULTS: There was a median delay of 42 days from the onset of symptom until confirmed diagnosis. All studied patients presented inability to walk; 79% had pain (more in older patients) and 17% had sphincteric dysfunction. A total of 58.3% had a single level of cord compression, 41.7% had multiple levels. Thoracic spine was commonly involved (41%). Final diagnosis was: neuroblastoma (29.2%), soft-tissue sarcomas (20.8%), neuroectodermal tumor (16.6%), non-Hodgkin lymphoma (12.5%), astrocytoma (4.2%), malignant teratoma (8.4%), Wilms tumor (4.2%), and leukemia (4.2%). Magnetic resonance imaging of the spine was diagnostic in all cases. A total of 83.3% of patients received emergency steroid therapy and 75% showed improvement. Disease-specific therapy was multimodality therapy in 88.5% with 71.42% showing improvement. Lymphomas had the best neurological outcome (100%) followed by soft-tissue sarcomas (80%) and neural tumors (72.7%). The 3-year overall survival was 79.2%. CONCLUSIONS: Spinal cord compression is a serious complication and unacceptable management delay can result in preventable loss of function. Emergency magnetic resonance imaging evaluation is the most sensitive diagnostic imaging. Majority of patients improve after definitive therapy.

Detection of KIAA1549-BRAF fusion transcripts in formalin-fixed paraffin-embedded pediatric low-grade gliomas.

Alterations of BRAF are the most common known genetic aberrations in pediatric gliomas. They frequently are found in pilocytic astrocytomas, where genomic duplications involving BRAF and the poorly characterized gene KIAA1549 create fusion proteins with constitutive B-Raf kinase activity. BRAF V600E point mutations are less common and generally occur in nonpilocytic tumors. The development of BRAF inhibitors as drugs has created an urgent need for robust clinical assays to identify activating lesions in BRAF. KIAA1549-BRAF fusion transcripts have been detected in frozen tissue, however, methods for FFPE tissue have not been reported. We developed a panel of FFPE-compatible quantitative RT-PCR assays for the most common KIAA1549-BRAF fusion transcripts. Application of these assays to a collection of 51 low-grade pediatric gliomas showed 97% sensitivity and 91% specificity compared with fluorescence in situ hybridization or array comparative genomic hybridization. In parallel, we assayed samples for the presence of the BRAF V600E mutation by PCR pyrosequencing. The data further support previous observations that these two alterations of the BRAF, KIAA1549 fusions and V600E point mutations, are associated primarily with pilocytic astrocytomas and nonpilocytic gliomas, respectively. These results show that fusion transcripts and mutations can be detected reliably in standard FFPE specimens and may be useful for incorporation into future studies of pediatric gliomas in basic science or clinical trials.

The potential protective role of alpha-lipoic acid against acetaminophen-induced hepatic and renal damage.

The potential protective role of alpha-lipoic acid (alpha-LA) in acetaminophen (APAP)-induced hepatotoxicity and nephrotoxicity was investigated in rats. Pretreatment of rats with alpha-LA (100mg/kg) orally protected markedly against hepatotoxicity and nephrotoxicity induced by an acute oral toxic dose of APAP (2.5 g/kg) as assessed by biochemical measurements and by histopathological examination. None of alpha-LA pretreated animals died by the acute toxic dose of APAP. Concomitantly, APAP-induced profound elevation of nitric oxide (NO) production and oxidative stress, as evidenced by increasing of lipid peroxidation level, reducing of glutathione peroxidase (GSH-Px) activity and depleting of intracellular reduced glutathione (GSH) level in liver and kidney, were suppressed by pretreatment with alpha-LA. Similarly, daily treatment of rats with a smaller dose of alpha-LA (25mg/kg) concurrently with a smaller toxic dose of APAP (750 mg/kg) for 1 week protected against APAP-induced hepatotoxicity and nephrotoxicity. This treatment also completely prevented APAP-induced mortality and markedly inhibited APAP-induced NO overproduction and oxidative stress in hepatic and renal tissues. These results provide evidence that inhibition of NO overproduction and maintenance of intracellular antioxidant status may play a pivotal role in the protective effects of alpha-LA against APAP-induced hepatic and renal damage.