Genome-wide DNA methylation profile in the peripheral blood of cocaine and crack dependents

Objective: Cocaine use disorders (CUDs) represent a major public health problem in many countries. To better understand the interaction between the environmental modulations and phenotype, the aim of the present study was to investigate the DNA methylation pattern of CUD patients, who had concomitant cocaine and crack dependence, and healthy controls. Methods: We studied DNA methylation profiles in the peripheral blood of 23 CUD patients and 24 healthy control subjects using the Illumina Infinium HumanMethylation450 BeadChip arrays. Results: Comparison between CUD patients and controls revealed 186 differentially methylated positions (DMPs; adjusted p-value [adjP] < 10-5) related to 152 genes, with a subset of CpGs confirmed by pyrosequencing. DNA methylation patterns discriminated CUD patients and control groups. A gene network approach showed that the EHMT1, EHMT2, MAPK1, MAPK3, MAP2K1, and HDAC5 genes, which are involved in transcription and chromatin regulation cellular signaling pathways, were also associated with cocaine dependence. Conclusion: The investigation of DNA methylation patterns may contribute to a better understanding of the biological mechanisms involved in CUD.

Intra-tumor genetic heterogeneity in Wilms tumor samples

SUMMARY Childhood renal tumors account for ~7% of all childhood cancers, and most cases are embryonic Wilms' tumors (WT). Children with WT are usually treated by either COG or SIOP. The later treats the children using preoperative chemotherapy, but both have around 90% of overall survival in five years. WT is a genetically heterogeneous group with a low prevalence of known somatic alterations. Only around 30% of the cases present mutation in known genes, and there is a relatively high degree of intra-tumor genetic heterogeneity (ITGH). Besides potentially having an impact on the clinical outcome of patients, ITGH may interfere with the search for molecular markers that are prospectively being tested by COG and SIOP. In this review, we present the proposal of the current UMBRELLA SIOP Study 2017/Brazilian Renal Tumor Group that requires the multi-sampling collection of each tumor to better evaluate possible molecular markers, as well as to understand WT biology

RESUMO Os tumores renais pediátricos correspondem a aproximadamente 7% de todos os tumores infantis, sendo o mais frequente o tumor de Wilms (TW). Crianças com TW são geralmente tratadas seguindo dois distintos protocolos terapêuticos (COG ou SIOP), sendo que no último, os pacientes recebem tratamento quimioterápico pré-operatório. Ambos apresentam sobrevida global em cinco anos em torno de 90%. TW é geneticamente heterogêneo, apresentando baixa prevalência de alterações somáticas conhecidas, com cerca de 30% dos casos apresentando mutações em genes conhecidos e um alto grau de heterogeneidade genética intratumoral (HGIT). Além de potencialmente ter um impacto sobre o desfecho clínico dos pacientes, a HGIT pode interferir na busca de marcadores moleculares que estão sendo testados prospectivamente pelos grupos COG e Siop. Nesta revisão, apresentamos a proposta do atual estudo Umbrella Siop 2017/Grupo de Tumores Renais Brasileiros (GTRB), que orienta a coleta de três diferentes regiões do tumor para melhor avaliar possíveis marcadores moleculares, bem como para compreender a biologia do TW.

Incidence and mortality of bone cancer among children, adolescents and young adults of Brazil

OBJECTIVES: Bone cancers occur frequently in children, adolescents, and young adults aging 15 to 29 years. Osteosarcoma and Ewing sarcoma are the most frequent subtypes in this population. The aim of this study was to describe incidence and mortality trends of bone cancers among Brazilian children, adolescents and young adults. METHODS: Incidence information was obtained from 23 population-based cancer registries. Mortality data were extracted from the Atlas of Cancer Mortality from 1979 to 2013. Specific and adjusted rates per million were analyzed according to gender, morphology and age at diagnosis. Median rates were used as a measure of central tendency. Joinpoint regression was applied to analyze trends. RESULTS: Median incidence rates were 5.74 and 11.25 cases per million in children and young adults respectively. Osteosarcoma in the 15-19 years aged group had the highest incidence rates. Stable incidence rates were observed among five registries in 0-14 year's age group. Four registries had a decreased incidence trend among adolescents and young adults. Median mortality rates were 1.22 and 5.07 deaths per million in children and young adults respectively. Increased mortality was observed on the North and Northeast regions. Decreased mortality trends were seen in the South (children) and Southeast (adolescents and young adults). CONCLUSION: Osteosarcoma and Ewing Sarcoma are the most incident bone cancers in all Brazilian regions. Bone cancers showed incidence and mortality patterns variation within the geographic regions and across age groups, although not significant. Despite limitations, it is crucial to monitor cancer epidemiology trends across geographic Brazilian regions.

Caracterização da expressão dos genes da via de sinalização WNT e do processo de transição epitélio-mesênquima durante a embriogênese de rim e suas implicações em tumores de Wilms / Gene expression characterization of WNT signaling pathway and epithelial-mesenchymal transition during kidney embryogenesis and their implications in Wilms tumors

O desenvolvimento do rim envolve interações complexas entre as células epiteliais e mesenquimais. Uma interrupção em qualquer passo crucial da progressão morfogenética pode levar a má formação renal e doenças, incluindo câncer. O tumor de Wilms (TW) ou nefroblastoma é originado pela interrupção da diferenciação das células do blastema metanéfrico resultando em um tumor composto por três componentes histológicos, blastema, epitélio e estroma... Nesse estudo, para identificar as alterações moleculares do início da diferenciação do rim e que são recapituladas no TW, a expressão de genes pertencentes às vias de transdução de sinal foi avaliada em células do blastema metanéfrico de quatro estágios temporais da diferenciação em camundongos (de 15,5 dias pós-coito até o rim completamente diferenciado), e em células do blastema de TWs e de rins diferenciados em humanos... O RNA total das células capturadas a laser foi amplificado e hibridado. Foram selecionados 18 genes, cuja expressão no início da diferenciação do rim foi recapitulada no TW, dos quais 11 foram menos expressos no tumor e apresentaram expressão crescente durante a nefrogênese e 7 foram mais expressos no tumor e apresentaram expressão decrescente durante a nefrogênese ... As alterações da expressão desses genes devem ser eventos precoces da interrupção da diferenciação que leva a transformação maligna. Adicionalmente, combinações de trios de genes foram avaliadas como marcadores preditivos de recaída em TW. O melhor trio composto por IGF2, TESK1 e PAX2, foi capaz de discriminar corretamente 85,71% das amostras quanto a recaída e não recaída. Esse estudo contribuiu para a identificação de novos genes associados com o aparecimento do TW, e como são alterações moleculares precoces, provavelmente são desencadeadoras do aparecimento do TW. Dessa forma, são candidatos apropriados para serem testados como alvos terapêuticos e marcadores moleculares para auxiliar a prática diária do TW.

Kidney development involves complex interactions between epithelial and mesenchymal cells. A disruption at any crucial step of the morphogenetic progression may lead to kidney malformations and diseases, including cancer. Wilms tumor (WT) or nephroblastoma originates from the metanephric blastema cells, which were unable to complete the differentiation process, resulting in a tumor composed by three histological components, blastema, epithelia and stroma. Blastemal component presents molecular characteristics which are highly similar to the earliest stages of kidney development, suggesting that it retains the key molecular events responsible for WT onset. Deregulation of signal transduction pathways has showed to be an important factor for interruption of renal differentiation, and probably for the WT onset. In this study, aiming to identify the early molecular alterations potentially involved in WT arising, the expression pattern of genes belonging to the transduction signaling pathways was evaluated in cells of the metanephric blastema in four temporal differentiation stages from 15,5 days post-coitum to the fully differentiated kidney in mice, and in blastemal cells of WT and human differentiated kidneys. To evaluate nephrogenesis in mice and WT in humans, we developed a model that allows the hybridization of target molecules of both species in the same cDNA microarray platform. Three hundred and twenty-six stretches of orthologous genes from humans and mice that share high similarity at nucleotide level were immobilized on a glass platform. Wnt signaling pathway, phosphatidylinositol (PI3K) and genes related to epithelial-mesenchymal transition and epithelial-mesenchymal (EMT/MET), associated to the embryonic development, were among the evaluated pathways. Blastemal cells were laser captured from 24 WT samples at four stages of nephrogenesis. Total RNA from these samples was amplified and hybridized in the platform. Eighteen genes were selected, whose expression in the initial of kidney differentiation were also observed in WT, where 11 were down-regulated in WT and reported an increasing expression during nephrogenesis and 7 were up-regulated in WT and presented a decreasing expression during nephrogenesis. Non-supervised hierarchical clustering based on the expression of 18 genes grouped differentiated kidneys from both species, human and murine, and discriminated both from WT samples, which were grouped with the earliest kidney stages, validating the model proposed by this study. The 18 genes were assessed in independent groups of samples at mRNA and protein levels. Twelve out of 18 genes were selected for validation by quantitative RT-PCR in the initial sample set and the expression of 9 (75%) genes was confirmed. From the 9 genes, 5 (55.6%) were validated in an independent group of samples. At protein level, 8 genes were evaluated by immunohistochemistry in WT, during nephrogenesis and in differentiated kidneys in humans. Quantitative evaluation of protein expression was consistent with the results of mRNA expression for 5 (62.5%) genes. This study identified WNT5B, PI3KCA, FZD2, GRK7, TESK1 and TIMP3, which had not been previously associated to WT. Gene expression alterations may be the early events of the interruption of cell differentiation that leads to malignant transformation. Additionally, combinations of trios of genes were tested as predictors of WT relapse revealing IGF2, TESK1 and PAX2 as the best trio because it was able to correctly discriminate 85.71% of the samples. This study contributes to the identification of new genes associated to the WT onset and to the early molecular alterations, which are likely to trigger the WT arising. In this way, these genes are candidates to be tested for therapeutic targets and also for molecular markers to assist the daily WT practice.