Extraneural metastases in medulloblastoma / Mestástases extraneurais em moduloblastoma

Medulloblastoma is the most common childhood malignant tumor of central nervous system, but it may also occur in adults. It presents high invasive growth with spreading of tumor cells into the leptomeningeal space along the neuroaxis early in the course of the disease. Extraneural metastases are rare but frequently lethal, occurring only in 1 to 5 percent of patients, and are related, in the most of cases, to the presence of ventriculoperitoneal shunt. Here we characterize the clinical profile of five cases of medulloblastoma with systemic spreading of tumor cells, also comparing them to cases already described in the literature.

O meduloblastoma é o tumor maligno mais frequente do sistema nervoso central na infância, mas também pode ocorrer em adultos. Ele apresenta crescimento altamente invasivo com disseminação de células tumorais ao longo do neuroeixo precocemente no curso da doença. Metástases extraneurais são raras mas frequentemente letais, ocorrendo apenas em 1 a 5 por cento dos pacientes, e estão relacionadas, na maioria dos casos, a presença de derivação ventriculperitoneal. Neste artigo ,apresentamos o perfil de cinco casos de meduloblastoma com disseminção sistêmica das células tumorais, comparando-os com os casos já descritos na literatura.

Identification of COL6A1 as a differentially expressed gene in human astrocytomas

Diffuse infiltrating gliomas are the most common tumors of the central nervous system. Gliomas are classified by the WHO according to their histopathological and clinical characteristics into four classes: grade I (pilocytic astrocytoma), grade II (diffuse astrocytoma), grade III (anaplastic astrocytoma), and grade IV (glioblastoma multiforme). Several genes have already been correlated with astrocytomas, but many others are yet to be uncovered. By analyzing the public SAGE data from 21 patients, comprising low malignant grade astrocytomas and glioblastomas, we found COL6A1 to be differentially expressed, confirming this finding by real time RT-PCR in 66 surgical samples. To the best of our knowledge, COL6A1 has never been described in gliomas. The expression of this gene has significantly different means when normal glia is compared with low-grade astrocytomas (grades I and II) and high-grade astrocytomas (grades III and IV), with a tendency to be greater in higher grade samples, thus rendering it a powerful tumor marker.

Differential expression of E-cadherin gene in human neuroepithelial tumors

Cadherins are cell-to-cell adhesion molecules that play an important role in the establishment of adherent-type junctions by mediating calcium-dependent cellular interactions. The CDH1 gene encodes the transmembrane glycoprotein E-cadherin which is important in maintaining homophilic cell-cell adhesion in epithelial tissues. E-cadherin interacts with catenin proteins to maintain tissue architecture. Structural defects or loss of expression of E-cadherin have been reported as a common feature in several human cancer types. This study aimed to evaluate the expression of E-cadherin and their correlation with clinical features in microdissected brain tumor samples from 81 patients, divided into 62 astrocytic tumors grades I to IV and 19 medulloblastomas, and from 5 white matter non-neoplasic brain tissue samples. E-cadherin (CDH1) gene expression was analyzed by quantitative real-time polymerase chain reaction. Mann-Whitney, Kruskal-Wallis, Kaplan-Meir, and log-rank tests were performed for statistical analyses. We observed a decrease in expression among pathological grades of neuroepithelial tumors. Non-neoplasic brain tissue showed a higher expression level of CDH1 gene than did neuroepithelial tumors. Expression of E-cadherin gene was higher in astrocytic than embryonal tumors (P = 0.0168). Low-grade malignancy astrocytomas (grades I-II) showed higher CDH1 expression than did high-grade malignancy astrocytomas (grades III-IV) and medulloblastomas (P < 0.0001). Non-neoplasic brain tissue showed a higher expression level of CDH1 gene than grade I malignancy astrocytomas, considered as benign tumors (P = 0.0473). These results suggest that a decrease in E-cadherin gene expression level in high-grade neuroepithelial tumors may be a hallmark of malignancy in dedifferentiated tumors and that it may be possibly correlated with their progression and dissemination.

Dystrophin-glycoproteins associated in congenital muscular dystrophy: immunohistochemical analysis of 59 Brazilian cases

The congenital muscular dystrophies (CMD) are heterogeneous muscular diseases with early and dystrophic pattern on muscle biopsy. Many different subtypes have been genetically identified and most phenotypes not yet identified belong to the merosin-positive (MP) CMD subgroup. OBJECTIVE: To analyze the immunohistochemical expression of the main proteins of the dystrophin-glycoproteins associated complex in muscle biopsy of patients with different CMD phenotypes, for investigating a possible correlation with clinical and histopathological data. METHOD: Fifty-nine patients with CMD had clinical, histopathological and immunohistochemical data evaluated: 32 had MP-CMD, 23 CMD with merosin deficiency (MD-CMD), one Ullrich phenotype and three Walker-Warburg disease. RESULTS: Dystrophin and dysferlin were normal in all; among the patients with MD-CMD, merosin deficiency was partial in nine who showed the same clinical severity as those with total deficiency; the reduced expression of alpha-sarcoglycan (SG) and alpha-dystroglycan (DG) showed statistically significant correlation with severe MD-CMD phenotype. CONCLUSION: There is a greater relationship between merosin and the former proteins; among MP-CMD patients, no remarkable immunohistochemical/phenotypical correlations were found, although the reduced expression of beta-DG had showed statistically significant correlation with severe phenotype and marked fibrosis on muscular biopsy.

A distrofia muscular congênita (DMC) é doença muscular heterogênea, de início precoce e padrão histopatológico de distrofia. Diversos subtipos foram geneticamente identificados e os fenótipos ainda não identificados pertencem em geral ao subgrupo de DMC merosina-positiva (MP). OBJETIVO: Analisar a expressão imuno-histoquímica das principais proteínas do complexo distrofina-glicoproteínas associadas na biópsia muscular de pacientes com diferentes fenótipos de DMC, a fim de investigar uma eventual correlação com o quadro clínico e histopatológico. MÉTODO: Cinqüenta e nove pacientes com DMC foram avaliados clinicamente e sua biópsia muscular, histopatologica e imuno-histoquimicamente: 32 eram MP, 23 merosina-deficiente (MD), um mostrava fenótipo Ullrich e três síndrome de Walker-Warburg. RESULTADOS: Distrofina e disferlina foram normais em todos; nove pacientes MD apresentavam déficit parcial de merosina, porém com a mesma gravidade clínica daqueles com deficiência total. CONCLUSÃO: A hipoexpressão de a-sarcoglicana (SG) and a-distroglycan (DG) se correlacionou estatisticamente com o grave fenótipo MD, assim indicando maior correlação entre a merosina e as referidas proteínas; entre os pacientes MP, apesar da hipoexpressão de b-DG ter se correlacionado significativamente com fenótipo e histopatologia mais grave, não houve correlação clínica/imuno-histoquímica valorizável.

Ullrich congenital muscular dystrophy and Bethlem myopathy: clinical and genetic heterogeneity

Ullrich congenital muscular dystrophy (UCMD), due to mutations in the collagen VI genes, is an autosomal recessive form of CMD, commonly associated with distal joints hyperlaxity and severe course. A mild or moderate involvement can be occasionally observed. OBJECTIVE: To evaluate the clinical picture of CMD patients with Ullrich phenotype who presented decreased or absent collagen VI immunoreactivity on muscular biopsy. RESULTS: Among 60 patients with CMD, two had no expression of collagen V and their clinical involvement was essentially different: the first (3 years of follow-up) has mild motor difficulty; the second (8 years of follow-up) never acquired walking and depends on ventilatory support. A molecular study, performed by Pan et al. at the Thomas Jefferson University, demonstrated in the first a known mutation of Bethlem myopathy in COL6A1 and in the second the first dominantly acting mutation in UCMD and the first in COL6A1, previously associated only to Bethlem myopathy, with benign course and dominant inheritance. CONCLUSION: Bethlem myopathy should be considered in the differential diagnosis of UCMD, even in patients without fingers contractures; overlap between Ullrich and Bethlem phenotypes can be supposed.

A distrofia muscular congênita (DMC) com hiperextensibilidade articular distal (fenótipo Ullrich) associa-se a mutações nos genes do colágeno VI e corresponde a um grave quadro congênito de herança autossômica recessiva e curso progressivo, ocasionalmente mostrando menor gravidade. OBJETIVO: Avaliar o quadro clínico dos pacientes com DMC tipo Ullrich que apresentam imunoexpressão baixa ou ausente do colágeno VI na biópsia muscular. RESULTADOS: Entre 60 pacientes com DMC, dois mostravam imunomarcação negativa do colágeno VI. Mostravam-se clinicamente essencialmente diferentes: o primeiro, com 8 anos de idade e três de seguimento mostra leve dificuldade motora; o segundo, com 14 anos de idade e 8 de seguimento, não deambula e apresenta insuficiência respiratória. O estudo molecular, realizado na Thomas Jefferson University por Pan et al., revelou no primeiro, no gene COL6A1, mutação típica da miopatia de Bethlem, que tem curso benigno e herança autossômica dominante; e no segundo a primeira mutação de efeito dominante e do gene COL6A1, previamente associado apenas à miopatia de Bethlem. CONCLUSÃO: A miopatia de Bethlem deve constar no diagnóstico diferencial da DMC tipo Ullrich, mesmo na ausência das típicas contraturas dos dedos; pode existir sobreposição dos fenótipos Ullrich e Bethlem.

Clinical and molecular analysis of spinal muscular atrophy in brazilian patients

As amiotrofias espinhais progressivas (SMAs) constituem as doenças degenerativas de origem genética letais mais comuns do sistema nervoso central e mais freqüentes dentre as doenças autossômicas recessivas após a mucoviscidose. A incidência estimada das SMAs e de aproximadamente 1:10.000 nativivos. Clinicamente, as SMAs säo classificadas em mais grave (doença de Werdnig-Hoffmann, tipo I), intermediária (tipo II) e tardia e benigna (doença de Kugelberg-Welander, tipo III). O gene para os três tipos de SMAs foi mapeado no cromossomo 5q11.2-13.3. Foram identificados dois genes candidatos na mesma regiäo: SMN (sobrevida do neurônio motor) e NAIP (proteína inibidora de apoptose neuronal). Estudamos ambos genes em 87 pacientes brasileiros (20 tipo I, 14 tipo II e 53 tipo III) pertencentes a 74 famílias, utilizando as técnicas de PCR e SSCP. Foi encontrada deleçäo nos exons 7 e/ou 8 do gene SMN em 69 por cento das famílias: 16/20 na tipo I, 9/12 na tipo II e 26/42 na tipo III. Dentre as 51 famílias com deleçäo, 44 tiveram deleçäo no exon 5 do gene NAIP foi encontrada em 7/20 na tipo I, 2/12 na tipo II e 1/42 na tipo III. Näo foi encontrada deleçäo nos genes SMN e NAIP nos 112 progenitores, 26 irmandades assintomáticas e 104 controles normais. Näo houve correlaçäo entre deleçäo de um ou ambos genes com a gravidade do quadro clínico.