NRAS Q61R , BRAF V600E immunohistochemistry: a concomitant tool for mutation screening in melanomas

International audienceThe determination of NRAS and BRAF mutation status is a major requirement in the treatment of patients with metastatic melanoma. Mutation specific antibodies against NRAS(Q61R) and BRAF(V600E) proteins could offer additional data on tumor heterogeneity. The specificity and sensitivity of NRAS(Q61R) immunohistochemistry have recently been reported excellent. We aimed to determine the utility of immunohistochemistry using SP174 anti-NRAS(Q61R) and VE1 anti-BRAF(V600E) antibodies in the theranostic mutation screening of melanomas. 142 formalin-fixed paraffin-embedded melanoma samples from 79 patients were analyzed using pyrosequencing and immunohistochemistry. 23 and 26 patients were concluded to have a NRAS-mutated or a BRAF-mutated melanoma respectively. The 23 NRAS (Q61R) and 23 BRAF (V600E) -mutant samples with pyrosequencing were all positive in immunohistochemistry with SP174 antibody and VE1 antibody respectively, without any false negative. Proportions and intensities of staining were varied. Other NRAS (Q61L) , NRAS (Q61K) , BRAF (V600K) and BRAF (V600R) mutants were negative in immunohistochemistry. 6 single cases were immunostained but identified as wild-type using pyrosequencing (1 with SP174 and 5 with VE1). 4/38 patients with multiple samples presented molecular discordant data. Technical limitations are discussed to explain those discrepancies. Anyway we could not rule out real tumor heterogeneity. In our study, we showed that combining immunohistochemistry analysis targeting NRAS(Q61R) and BRAF(V600E) proteins with molecular analysis was a reliable theranostic tool to face challenging samples of melanoma

Comparison of Characteristics of Neuropathic and Non-neuropathic Pruritus to Develop a Tool for the Diagnosis of Neuropathic Pruritus: The NP5

The diagnosis of neuropathic pruritus (NP) may be difficult. The aim of this study was to compare the characteristics of both neuropathic pruritus and non-neuropathic pruritus (NNP) in order to elaborate a tool to help the diagnosis of NP without clinical examination. One hundred and seven patients were included: Fifty three in the NP group and Fifty four in the NNP group. In multiple regression, presence of twinges, absence of burning, worsening with activity, no worsening with stress, and relief with cold ambient temperature were independent factors that were associated with NP. A score of two criteria out of five was optimal to discriminate NP from NNP with a sensitivity of 76% and a specificity of 77%. Alloknesis, hyperknesis, or the ice cube test were not included because their evaluation is based on clinical examination. Future high-powered studies are needed to confirm the results of the present study

Fatal Case of Enterovirus 71 Infection, France, 2007

A fatal case of enterovirus 71 infection with pulmonary edema and rhombencephalitis occurred in Brest, France, in April 2007. The virus was identified as subgenogroup C2. This highly neurotropic enterovirus merits specific surveillance outside the Asia-Pacific region

Heterozygous frameshift variants in HNRNPA2B1 cause early-onset oculopharyngeal muscular dystrophy

Missense variants in RNA-binding proteins (RBPs) underlie a spectrum of disease phenotypes, including amyotrophic lateral sclerosis, frontotemporal dementia, and inclusion body myopathy. Here, we present ten independent families with a severe, progressive muscular dystrophy, reminiscent of oculopharyngeal muscular dystrophy (OPMD) but of much earlier onset, caused by heterozygous frameshift variants in the RBP hnRNPA2/B1. All disease-causing frameshift mutations abolish the native stop codon and extend the reading frame, creating novel transcripts that escape nonsense-mediated decay and are translated to produce hnRNPA2/B1 protein with the same neomorphic C-terminal sequence. In contrast to previously reported disease-causing missense variants in HNRNPA2B1, these frameshift variants do not increase the propensity of hnRNPA2 protein to fibrillize. Rather, the frameshift variants have reduced affinity for the nuclear import receptor karyopherin β2, resulting in cytoplasmic accumulation of hnRNPA2 protein in cells and in animal models that recapitulate the human pathology. Thus, we expand the phenotypes associated with HNRNPA2B1 to include an early-onset form of OPMD caused by frameshift variants that alter its nucleocytoplasmic transport dynamics

CD133 Is a Marker of Bioenergetic Stress in Human Glioma

Mitochondria dysfunction and hypoxic microenvironment are hallmarks of cancer cell biology. Recently, many studies have focused on isolation of brain cancer stem cells using CD133 expression. In this study, we investigated whether CD133 expression is regulated by bioenergetic stresses affecting mitochondrial functions in human glioma cells. First, we determined that hypoxia induced a reversible up-regulation of CD133 expression. Second, mitochondrial dysfunction through pharmacological inhibition of the Electron Transport Chain (ETC) produced an up-regulation of CD133 expression that was inversely correlated with changes in mitochondrial membrane potential. Third, generation of stable glioma cells depleted of mitochondrial DNA showed significant and stable increases in CD133 expression. These glioma cells, termed rho0 or ρ0, are characterized by an exaggerated, uncoupled glycolytic phenotype and by constitutive and stable up-regulation of CD133 through many cell passages. Moreover, these ρ0 cells display the ability to form “tumor spheroids” in serumless medium and are positive for CD133 and the neural progenitor cell marker, nestin. Under differentiating conditions, ρ0 cells expressed multi-lineage properties. Reversibility of CD133 expression was demonstrated by transfering parental mitochondria to ρ0 cells resulting in stable trans-mitochondrial “cybrid” clones. This study provides a novel mechanistic insight about the regulation of CD133 by environmental conditions (hypoxia) and mitochondrial dysfunction (genetic and chemical). Considering these new findings, the concept that CD133 is a marker of brain tumor stem cells may need to be revised

Role of cytoskeletal abnormalities in the neuropathology and pathophysiology of type I lissencephaly

Type I lissencephaly or agyria-pachygyria is a rare developmental disorder which results from a defect of neuronal migration. It is characterized by the absence of gyri and a thickening of the cerebral cortex and can be associated with other brain and visceral anomalies. Since the discovery of the first genetic cause (deletion of chromosome 17p13.3), six additional genes have been found to be responsible for agyria–pachygyria. In this review, we summarize the current knowledge concerning these genetic disorders including clinical, neuropathological and molecular results. Genetic alterations of LIS1, DCX, ARX, TUBA1A, VLDLR, RELN and more recently WDR62 genes cause migrational abnormalities along with more complex and subtle anomalies affecting cell proliferation and differentiation, i.e., neurite outgrowth, axonal pathfinding, axonal transport, connectivity and even myelination. The number and heterogeneity of clinical, neuropathological and radiological defects suggest that type I lissencephaly now includes several forms of cerebral malformations. In vitro experiments and mutant animal studies, along with neuropathological abnormalities in humans are of invaluable interest for the understanding of pathophysiological mechanisms, highlighting the central role of cytoskeletal dynamics required for a proper achievement of cell proliferation, neuronal migration and differentiation

Bilan des lésions foetales et placentaires rencontrées au cours de l'exposition à l'alcool in utero

Les effets de l'alcoolisation maternelle sur le foetus sont un véritable problème de santé publique. Leur prévention passe par une identification des patientes à risque de consommation excessive, ce dépistage difficile, avant tout clinique, pouvant s'aider de paramètres biologiques mais aussi des apports de l'anatomie pathologique en terme d'examen placentaire et parfois foetopathologique. Cette étude basée sur 67 examens placentaires et 15 examens foetaux décrit les lésions placentaires parfois évocatrices d'un tableau d'exposition foetal à l'alcool et les différents syndromes liés à l'alcoolisation foetale dont le syndrome d'alcoolisation foetale et les anomalies congénitales liées à l'alcool sont des diagnostic possible en foetopathologie dès les premières semaines de la vie, selon des critères proches de ceux utilisés en pédiatrie. En dehors d'une synthèse concernant la tératogénicité de l'alcool sur un plan descriptif mais aussi physiopathologique, cette étude conclut sur la nécessité de diagnostiquer ce trouble addictif maternel afin d'assurer un prise en charge adaptée du couple mère-enfant et de prévenir les récidives d'une pathologie fréquente, grave, souvent méconnue et pourtant curable.BREST-BU Médecine-Odontologie (290192102) / SudocSudocFranceF

Expressions phénotypiques au cours du développement humain de deux pathologies (la mucoviscidose et les anomalies de migration neuronale)

L expression phénotypique de protéines impliquées dans la physiopathologie de maladies géniques a été étudiée dans deux types de pathologies l une non malformative, l autre malformative. Les anomalies morphologiques foetales et l expression de la protéine CFTR ont été recherchées dans la mucoviscidose. Au niveau broncho-pulmonaire, un retard d expression de 3 semaines, une intensité maximale et une topographie diffuse précoce puis une décroissance spatiale et en intensité de signal ont été trouvées. Des signes de destruction de l appareil excréteur génital male ont été mis en évidence parallèlement à l expression précoce de la protéine, persistant mais ne comportant pas de gradient d intensité à l inverse des tissus adultes. Il apparaît un renforcement apical de l expression parallèlement à la différentiation tissulaire épithéliale. L expression précoce et intense de la protéine CFTR, sa cinétique, sa localisation cytoplasmique puis avec renforcement apical évoquent un rôle particulier pendant lé développement. Les lissencéphalies de type 1 forment un groupe hétérogène d anomalies de migration neuronale. L expression des protéines de liaison du calcium (calrétinine, calbindine, parvalbumine) qui colocalisent avec l acide gamma-aminobutyrique (GABA) au niveau des interneurones a été étudiée dans trois syndromes lissencephaliques par atteinte des gènes LISI, DCX, ARX. Ceci a permis de mettre de comparer les anomalies de la migration tangentielle et de la migration radiaire confirmant l hypothèse d une atteinte différente des interneurones selon le gène incriminé. Ces altérations établissent un rôle majeur aux interneurones lors des étapes critiques du développement.The morphological analysis and the expression of several proteins have been performed in two different genetic disorders, the former without malformation the later with malformation. The pattern of expression of the CFTR protein has been analysed in the respiratory tract and in the male genital excretory tract. The CFTR expression appeared with a 3- week delay in the respiratory tract; had a different pattern of spatial expression according to the tissue differentiation. In the genital tract, the expression of die protein remained diffuse without any gradient of intensity conversely to the adult pattern. The early and diffuse localisation of the CFTR protein raises the question of its role during development. Neuronal migration anomalies form a large group in which type 1 lissencephaly group of disorders belongs. We studied the calcium binding proteins to analyse the GABAergic interneurons in three agyric/pachygyric syndromes dues to defects in the LISJ, DCX, ARX genes. GABAergic neurons migration was disturbed in a particular pattern in each case. These data argue for impairment in both the radial telencephalic migration and the tangential telencephalic migration in these different disorders.BREST-BU Médecine-Odontologie (290192102) / SudocSudocFranceF