Noonan syndrome, PTPN11 mutations, and brain tumors. A clinical report and review of the literature.

Noonan syndrome (NS), an autosomal dominant disorder, is characterized by short stature, congenital heart defects, developmental delay, and facial dysmorphism. PTPN11 mutations are the most common cause of NS. PTPN11 encodes a non-receptor protein tyrosine phosphatase, SHP2. Hematopoietic malignancies and solid tumors are associated with NS. Among solid tumors, brain tumors have been described in children and young adults but remain rather rare. We report a 16-year-old boy with PTPN11-related NS who, at the age of 12, was incidentally found to have a left temporal lobe brain tumor and a cystic lesion in the right thalamus. He developed epilepsy 2 years later. The temporal tumor was surgically resected because of increasing crises and worsening radiological signs. Microscopy showed nodules with specific glioneuronal elements or glial nodules, leading to the diagnosis of dysembryoplastic neuroepithelial tumor (DNT). Immunohistochemistry revealed positive nuclear staining with Olig2 and pERK in small cells. SHP2 plays a key role in RAS/MAPK pathway signaling which controls several developmental cell processes and oncogenesis. An amino-acid substitution in the N-terminal SHP2 domain disrupts the self-locking conformation and leads to ERK activation. Glioneuronal tumors including DNTs and pilocytic astrocytomas have been described in NS. This report provides further support for the relation of DNTs with RASopathies and for the implication of RAS/MAPK pathways in sporadic low-grade glial tumors including DNTs. © 2017 Wiley Periodicals, Inc.

Clinical, pathological, and molecular data on desmoplastic/nodular medulloblastoma: case studies and a review of the literature.

The aim of this study was to better define the clinical and biopathological features of patients with desmoplastic/nodular medulloblastoma (DNMB) and to further characterize this subgroup. 17 children aged < 5 years, with initial DNMB treated according to the HIT-SKK protocol, were evaluated. A retrospective central radiological review, a pathological and immunohistochemical study, and array-CGH and sequencing of germline SUFU and PTCH1 genes were performed. 15 histologically reviewed cases were confirmed as DNMB including three cases of medulloblastoma with extensive nodularity. Median age at diagnosis was 26 months. Radiology showed five cases with a vermis location and one with T2 hyperintensity. All cases showed a SHH immunoprofile. A 9q deletion was found in 6 cases, a MYCN-MYCL amplification in 1 case, and a SUFU germline mutation in 1 case (/9). The presence of SUFU and PTCH1 germline mutations agreed with previous reports. At 3 years, progression-free survival and overallsurvival rates were 72 ± 15% and 85 ± 10%, respectively. The rate of recurrence was relatively high (4 patients). This may have been because chemotherapy was delayed in two cases. Age > 3 years, and residual tumor may also have been an explanation for recurrence.

Embryonal tumor with multilayered rosettes: diagnostic tools update and review of the literature.

Embryonal tumor with multilayered rosettes (ETMR), including embryonal tumor with abundant neuropil and true rosettes (ETANTR), and ependymoblastoma (EBL) constitute a distinct entity of the primitive neuroectodermal tumor (PNET) family. The presence of a focal amplification at chromosome region 19q13.42 associated with an up-regulation of the oncogenic miRNA cluster C19MC suggests that they may represent a histological spectrum of a single biological entity. Their histopathological spectrum is wide, including medulloepithelioma, their location may be supra- or infra-tentorial, their prognosis is poor. Recent data on molecular subgroups of PNETs have led to new insights on diagnosis and treatment of these tumors. Subsequently, LIN28A immunoexpression was identified as a highly specific marker for ETMR. In this study, we report 4 cases diagnosed initially as ETANTR with CGH-array data, including 19q13.42 gain with absence of other amplicons, particularly of the MYC gene family, and inconstant gain of whole chromosome 2. Immunohistochemical positive expression of LIN28A and absence of Olig2 expression were observed. We summarize the literature on ETMR, pointing out on the nosological evolution of this entity and the findings on genetic hallmarks of this particular tumor. Our results emphasize the usefulness of immunohistochemistry as a highly sensitive and fast diagnostic tool for ETMR and for genetic data, especially for 19q13.42 locus. Biological features may offer new therapeutic options for these embryonal tumors that do not usually respond to conventional treatments of PNETs.

Radiosynthesis of [18F]AV1451 in pharmaceutical conditions and its biological characteristics.

In this study, we describe the radiosynthesis of [18F]AV1451 in terms of its pharmaceutical quality and characterise its physical and biological properties. We performed an in vitro serum stability study in fresh human plasma and a plasma protein binding study. The radiochemical yield was 24% (decay corrected), and the product met all regulatory quality requirements. We found that this compound is stable in fresh human plasma and binds tightly to plasma proteins, especially lipoproteins.

Reduced sphingosine kinase-1 and enhanced sphingosine 1-phosphate lyase expression demonstrate deregulated sphingosine 1-phosphate signaling in Alzheimer's disease.

BACKGROUND: The accumulation of beta amyloid (Aß) peptides, a hallmark of Alzheimer's disease (AD) is related to mechanisms leading to neurodegeneration. Among its pleiotropic cellular effects, Aß accumulation has been associated with a deregulation of sphingolipid metabolism. Sphingosine 1-phosphate (S1P) derived from sphingosine is emerging as a critical lipid mediator regulating various biological activities including cell proliferation, survival, migration, inflammation, or angiogenesis. S1P tissue level is low and kept under control through equilibrium between its synthesis mostly governed by sphingosine kinase-1 (SphK1) and its degradation by sphingosine 1-phosphate lyase (SPL). We have previously reported that Aß peptides were able to decrease the activity of SphK1 in cell culture models, an effect that could be blocked by the prosurvival IGF-1/IGF-1R signaling. RESULTS: Herein, we report for the first time the expression of both SphK1 and SPL by immunohistochemistry in frontal and entorhinal cortices from 56 human AD brains. Immunohistochemical analysis revealed a decreased expression of SphK1 and an increased expression of SPL both correlated to amyloid deposits in the entorhinal cortex. Otherwise, analysis of brain tissue extracts showed a decrease of SphK1 expression in AD brains whereas SPL expression was increased. The content of IGF-1R, an activator of SphK1, was found decreased in AD brains as well as S1P1, the major receptor for S1P. CONCLUSIONS: Collectively, these results highlight the importance of S1P in AD suggesting the existence of a global deregulation of S1P signaling in this disease from its synthesis by SphK1 and degradation by SPL to its signaling by the S1P1 receptor.