Activation of the MAPK signaling pathway has been shown to be a unifying molecular feature in pilocytic astrocytoma (PA). Genetically, tandem duplications at chromosome 7q34 resulting in KIAA1549-BRAF fusion genes constitute the most common mechanism identified to date. To elucidate alternative mechanisms of aberrant MAPK activation in PA, we screened 125 primary tumors for RAF fusion genes and mutations in KRAS, NRAS, HRAS, PTPN11, BRAF and RAF1. Using microarray-based comparative genomic hybridization (aCGH), we identified in three cases an interstitial deletion of ~2.5 Mb as a novel recurrent mechanism forming BRAF gene fusions with FAM131B, a currently uncharacterized gene on chromosome 7q34. This deletion removes the BRAF N-terminal inhibitory domains, giving a constitutively active BRAF kinase. Functional characterization of the novel FAM131B-BRAF fusion demonstrated constitutive MEK phosphorylation potential and transforming activity in vitro. In addition, our study confirmed previously reported BRAF and RAF1 fusion variants in 72% (90/125) of PA. Mutations in BRAF (8/125), KRAS (2/125) and NF1 (4/125) and the rare RAF1 gene fusions (2/125) were mutually exclusive with BRAF rearrangements, with the exception of two cases in our series that concomitantly harbored more than one hit in the MAPK pathway. In summary, our findings further underline the fundamental role of RAF kinase fusion products as a tumor-specific marker and an ideally suited drug target for PA.

Pilocytic astrocytoma (PA) is emerging as a tumor entity with dysregulated Ras/Raf/MEK/ERK signaling. Common genetic lesions observed in PA, which are linked to aberrant ERK pathway activity, include either NF1 inactivation, KRAS or BRAF gainof-function mutations. To investigate the mutation spectrum within the proto-oncogene encoding the Ser/Thr-kinase B-Raf in more detail, we analyzed 64 primary tumor samples from children with PA including two patients with neurofibromatosis type 1 (NF1). The well-known BRAF V600E mutation was found in 6/64 (9.38%) of our samples. For the first time, we report concomitant presence of a somatic BRAF V600E mutation in an NF1 patient indicating that more than one Ras/ERK pathway component can be affected in PA. Furthermore, 2/64 (3.13%) of our samples carried a 3-bp insertion in BRAF resulting in the duplication of threonine 599. This conserved residue is located within the activation segment and, if phosphorylated in a Ras-dependent manner, plays a key role in Raf activation. Here, we demonstrate that this mutant (B-Raf insT ) and another B-Raf mutant, which carries two additional threonine residues at this position, display an in vitro kinase activity and cellular MEK/ ERK activation potential comparable to those of B-Raf V600E . Notably, replacement of threonines by valine residues had similar effects on B-Raf activity, suggesting that the distortion of the peptide backbone by additional amino acids rather than the insertion of additional, potential phosphorylation sites destabilizes the inactive conformation of the kinase domain. We also demonstrate that B-Raf insT and B-Raf V600E , but not B-Raf wt , provoke drastic morphological alterations in human astrocytes.B-Raf plays a pivotal role in the activation of the Ras/Raf/ MEK/ERK pathway, which controls cellular proliferation, survival and differentiation. 1,2 B-Raf is highly expressed in neuronal tissues and is involved in various brain functions.3 A key event in B-Raf activation is its interaction with activated Ras (Ras-GTP) and the associated phosphorylation of the LAT 599 VKS 602 -motif within the activation segment, which is encoded by exon 15. 4 Phosphorylation of T599 and S602 reorientates the activation segment and induces full kinase activity.5 Structural analyses revealed that, in inactive B-Raf, a hydrophobic interaction between F468 of the glycine-rich P-loop and V600 within the activation segment orientates the ATP-coordinating DFG motif to a position that is incompatible with catalysis.5 Upon LATVKS-motif phosphorylation, however, this hydrophobic interaction is disrupted, and the DFG motif is reorientated in such a manner that an efficient phosphotransferase reaction can occur.Dysregulated B-Raf signaling is of growing importance in oncology and is currently being targeted through the development and clinical application of B-Raf and MEK inhibitors.

AIM: The aim of the study was to investigate the role of umbilical cord blood lactate as early predictors of hypoxic ischemic encephalopathy in newborns with perinatal asphyxia and to evaluate their sensitivity and specificity for the early identification of hypoxic ischemic encephalopathy infants. METHODS: We performed а descriptive cross sectionаl study between Аpril 2014 аnd Аpril 2015 аt Hue Central Hospital, Vietnаm. 41 аsphyxiа newborns (Apgar score ≤ 7) were included in the study. Umbilicаl cord blood is sаmpled for lаctаte аnаlysis. RESULTS: Umbilicаl cord blood lаctаte levels were significаntly higher аmong infаnts born with HIE (meаn 8.72 ± 1.75, rаnge 5.12 – 11.96) compаred to thаt with asphyxic infаnts without HIE (meаn 6.86 ± 1.33, rаnge 4.74 – 10.30), p = 0.00. With the optimаl cutoff point for umbilicаl cord blood lаctаte level of 8.12 mmol/l to susspected of HIE (аreа under the curve 0.799) hаd а sensitivity 73.7% (95% CI: 48.8-90.9), specificity 86.4% (95% CI: 65.1-97.1). CONCLUSION: Umbilical cord blood lactate could be used as early predictors in diagnosis of hypoxic ischemic encephalopathy in newborns with asphyxia.

Plasma lactate dehydrogenase (LDH) is an indicator of body tissue hypoxia. This study aimed to determine the relationship between plasma lactate dehydrogenase concentrations and severe conditions in newborn infants. Patients and Methods: A cross-sectional study was performed on newborn infants who were admitted to the newborn care unit at Hue University hospital from April 2016 to May 2017 in the early neonatal period (within 12 hours postpartum). Plasma LDH was measured at the time of admission and correlated to clinical conditions. Results: In 275 newborn infants, plasma LDH levels in the term infants were significantly higher than that in the preterm infants [751 (IQR: 602-922) vs 594 (IQR: 496.75-767.25), p=0.0006]. There was a relationship between the signs of feeding problems, tachypnea, and cyanosis with plasma LDH levels (p < 0.01). Infants with asphyxia had significantly higher LDH values than the non-asphyxia group [756 (640-1110) vs 712 (576-882.25) p=0.0289]. Infants with early-onset neonatal sepsis had significantly higher LDH values than those without early-onset neonatal sepsis [755.5 (IQR: 645-960.5) vs 707 (IQR: 562.25-881.25) p=0.0035]. Infants with respiratory distress requiring continuous positive airway pressure (CPAP) had significantly higher LDH values than those with illnesses not requiring CPAP [903 (IQR: 628.75-1285.25) vs 719 (IQR: 576.5-882) p=0.0421]. By using multivariate regression analysis, we found a significant multifactorial correlation between gestational age, early-onset neonatal sepsis, asphyxia, and respiratory distress requiring CPAP with plasma LDH levels (p <0.05). Conclusion:Plasma LDH level can be a good marker for the prognosis of severe conditions in newborn infants, including early-onset neonatal sepsis, asphyxia, and respiratory-distress.

Introduction: This study aimed to determine the incidence of lower genital infections and related factors in preterm premature rupture of membranes (PPROM) and preterm labor. Methodology: A case-control study was conducted on pregnant women who were admitted to the Hospital of Hue University of Medicine and Pharmacy, Vietnam between November 2017 and May 2019. Cases from 22 to 36 gestational weeks were included as group 1 (patients with preterm labor and intact membranes) or as group 2 (those with PPROM). The control group included women with singleton pregnancies who were matched on gestational age and recruited concurrently with the study cases. Gram stain was perfomed to identify Lactobacillus, Gardnerella, mobiluncus, Candida, and leucocytes. Trichomonas vaginalis was detected by wet mount. Cultures of vaginal secretions and aminotic fluid were performed to identify aerobic bacteria. Results: Bacterial vaginosis was higher in group 1 (28.9%) compared to control (11.4%). The incidence of isolated aerobic bacteria was 44.1% in group 2, 11.1% in group 1, and 12.7% in the control group (p < 0.001). Fungal infection was not shown to be a risk factor for preterm labor (p = 0.990), whereas, bacterial vaginosis was (OR = 3.16; 95%CI = 1.23-8.15; p = 0.016). Isolated aerobic bacteria were associated with premature rupture of membranes (OR = 5.45; 95%CI = 2.11-14.05; p < 0.001). Conclusions: Bacteria vaginosis increased the risk of preterm labor and preterm premature rupture of membranes. Isolated aerobic bacteria were related to PPROM, while fungal infection was not associated with preterm labor.