hTERT gene methylation in circulating DNA, tumor, and surrounding tissue in breast cancer: a prospective study.

BACKGROUND: The human telomerase reverse transcriptase (hTERT) enzyme, encoded by the hTERT gene, synthesizes protective telomeric sequences on chromosomes and plays a fundamental role in cancer formation. Methylation of the hTERT gene has an upregulatory effect, increasing hTERT enzyme synthesis and allowing continuous tumor cell division. OBJECTIVE: In a group of patients with breast cancer, we aimed to analyze the methylation status of hTERT in the tumor, surrounding tissue, and circulating free deoxyribonucleic acid (cfDNA) of blood collected on the day of mastectomy and then approximately one year later. DESIGN AND SETTING: A prospective study was conducted at a university hospital in Rio de Janeiro, Brazil. METHODS: Samples were collected from 15 women with breast cancer on the day of mastectomy and approximately one year postoperatively. cfDNA was analyzed by sodium bisulfite conversion, followed by polymerase chain reaction, electrophoresis, and silver nitrate staining. RESULTS: Methylation of hTERT was detected in the tumors and surrounding tissues of all 15 patients. Five patients displayed hTERT methylation in the cfDNA from the blood of the first collection. Of the ten patients who returned for the second collection, three showed methylation. Two patients with methylation in the first collection did not display methylation in the second collection. One patient with no methylation in the first collection displayed methylation in the second collection, and one patient had a diminished level of methylation in the second collection. CONCLUSION: Only one-third of patients displayed methylation in their cfDNA, which may be related to the success of chemotherapy.

Molecular monitoring by CDKN2A/p16INK4A and RB1 gene methylation in breast cancer.

OBJECTIVE: This prospective study aimed to provide a comprehensive analysis of the methylation status of two pivotal genes, CDKN2A/p16INK4A (cyclin-dependent kinase inhibitor 2A) and RB1 (retinoblastoma transcriptional corepressor 1), in breast cancer patients. METHODS: Samples were obtained from 15 women diagnosed with breast cancer and who underwent a total mastectomy. DNA was extracted from the tumor, non-tumor tissue, and peripheral blood (circulating cell-free DNA). The methylation pattern of cell-free DNA extracted from blood collected on the day of mastectomy was compared with the methylation pattern of cell-free DNA from blood collected 1 year post-surgery. The methylation analysis was carried out by sodium bisulfite conversion and polymerase chain reaction, followed by electrophoresis. RESULTS: Methylation of CDKN2A/p16INK4A was identified in 13 tumor samples and 12 non-tumor tissue samples. Two patients exhibited CDKN2A/p16INK4A methylation in the cell-free DNA of the first blood collection, while another showed methylation only in the cell-free DNA of the subsequent blood collection. Regarding RB1, 11 tumors and 8 non-tumor tissue samples presented methylation of the gene. CONCLUSION: This study presents a novel approach for monitoring breast cancer patients through the analysis of cell-free DNA methylation. This analysis can detect changes in methylation patterns before any visible sign of cancer appears in breast tissue and could help predict the recurrence of malignant breast tumors.

Molecular monitoring by CDKN2A/p16INK4A and RB1 gene methylation in breast cancer

SUMMARY OBJECTIVE: This prospective study aimed to provide a comprehensive analysis of the methylation status of two pivotal genes, CDKN2A/p16INK4A (cyclin-dependent kinase inhibitor 2A) and RB1 (retinoblastoma transcriptional corepressor 1), in breast cancer patients. METHODS: Samples were obtained from 15 women diagnosed with breast cancer and who underwent a total mastectomy. DNA was extracted from the tumor, non-tumor tissue, and peripheral blood (circulating cell-free DNA). The methylation pattern of cell-free DNA extracted from blood collected on the day of mastectomy was compared with the methylation pattern of cell-free DNA from blood collected 1 year post-surgery. The methylation analysis was carried out by sodium bisulfite conversion and polymerase chain reaction, followed by electrophoresis. RESULTS: Methylation of CDKN2A/p16INK4A was identified in 13 tumor samples and 12 non-tumor tissue samples. Two patients exhibited CDKN2A/p16INK4A methylation in the cell-free DNA of the first blood collection, while another showed methylation only in the cell-free DNA of the subsequent blood collection. Regarding RB1, 11 tumors and 8 non-tumor tissue samples presented methylation of the gene. CONCLUSION: This study presents a novel approach for monitoring breast cancer patients through the analysis of cell-free DNA methylation. This analysis can detect changes in methylation patterns before any visible sign of cancer appears in breast tissue and could help predict the recurrence of malignant breast tumors.

hTERT gene methylation in circulating DNA, tumor, and surrounding tissue in breast cancer: a prospective study

ABSTRACT BACKGROUND: The human telomerase reverse transcriptase (hTERT) enzyme, encoded by the hTERT gene, synthesizes protective telomeric sequences on chromosomes and plays a fundamental role in cancer formation. Methylation of the hTERT gene has an upregulatory effect, increasing hTERT enzyme synthesis and allowing continuous tumor cell division. OBJECTIVE: In a group of patients with breast cancer, we aimed to analyze the methylation status of hTERT in the tumor, surrounding tissue, and circulating free deoxyribonucleic acid (cfDNA) of blood collected on the day of mastectomy and then approximately one year later. DESIGN AND SETTING: A prospective study was conducted at a university hospital in Rio de Janeiro, Brazil. METHODS: Samples were collected from 15 women with breast cancer on the day of mastectomy and approximately one year postoperatively. cfDNA was analyzed by sodium bisulfite conversion, followed by polymerase chain reaction, electrophoresis, and silver nitrate staining. RESULTS: Methylation of hTERT was detected in the tumors and surrounding tissues of all 15 patients. Five patients displayed hTERT methylation in the cfDNA from the blood of the first collection. Of the ten patients who returned for the second collection, three showed methylation. Two patients with methylation in the first collection did not display methylation in the second collection. One patient with no methylation in the first collection displayed methylation in the second collection, and one patient had a diminished level of methylation in the second collection. CONCLUSION: Only one-third of patients displayed methylation in their cfDNA, which may be related to the success of chemotherapy.

Epstein-Barr virus in gastric cancer and association with 30 bp del-latent membrane protein 1 polymorphism

SUMMARY OBJECTIVE: This study aimed to determine the frequencies of Epstein-Barr virus, types 1 and 2 infection, and 30 bp del-latent membrane protein 1 viral polymorphism in gastric adenocarcinomas, as well as to investigate the association between Epstein-Barr virus infection and tumor location, type, and the patient's sex. METHODS: Samples were collected from 38 patients treated at a university hospital in Rio de Janeiro, Brazil. Epstein-Barr virus detection and genotyping were performed by polymerase chain reaction, followed by polyacrylamide gel electrophoresis and staining by the silver nitrate method. RESULTS: Overall, 68.4% of patients had Epstein-Barr virus-positive tumors. Of these, 65.4% presented infection by Epstein-Barr virus type 1, 23.1% by Epstein-Barr virus type 2, and 11.5% had coinfection with types 1 and 2. The 30 bp del-latent membrane protein 1 polymorphism was found in 42.3% of Epstein-Barr virus-positive tumors, 23.1% had the wild-type virus, and 23.1% had the wild-type and the polymorphism concomitantly. In 11.5% of Epstein-Barr virus-positive tumors, it was impossible to determine whether there was polymorphism or not. Tumor location in the antrum (22 of 38) and diffuse type (27 of 38) were predominant. There was no significant difference in Epstein-Barr virus infection or the 30 bp del-latent membrane protein 1 polymorphism between men and women. CONCLUSION: Epstein-Barr virus infection was found in 68.4% of tumors investigated in this study. To the best of our knowledge, this is the first article showing the coinfection of Epstein-Barr virus types 1 and 2 in gastric carcinoma in Brazil.

Análise comparativa do polimorfismo genético da glutationa transferase, do Helicobacter pylori e do vírus Epstein-Barr entre a área do tumor e as margens de ressecção proximal e distal do câncer gástrico / Comparative analysis of glutathione transferase genetic polymorphism, Helicobacter pylori and Epstein-Barr virus between the tumor area and the proximal and distal resection margins of gastric cancer

RESUMO Objetivo: comparar o polimorfismo dos genes Glutationa S-transferase teta 1 (GSTT1) e Glutationa S-transferase mu 1 (GSTM1) da área do tumor com as margens proximal e distal de espécimes de estômago ressecados de pacientes com câncer gástrico, e investigar a presença do DNA do vírus Epstein-Barr (EBV) e Helicobacter pylori. Métodos: coletamos prospectivamente amostras teciduais da área do tumor e das margens de ressecção proximal e distal dos estômagos de dez pacientes com adenocarcinoma gástrico submetidos à gastrectomia com linfadenectomia D2 e submetemos esses espécimes à extração de DNA. Comparamos a área do tumor com as margens proximal e distal dos estômagos ressecados para o polimorfismo dos genes GSTT1 e GSTM1 e investigamos a presença de DNA do EBV e H. pylori. Utilizamos o exon 5 do gene p53 como controle interno da reação de PCR multiplex. Resultados: em um paciente, detectamos genótipos GSTT1 e GSTM1 nulos na área do tumor, em contraste com a presença de ambos os genes nas margens proximal e distal. Encontramos DNA do EBV e H. pylori na área do tumor e também nas margens proximal e distal. Em outro paciente, a margem proximal foi negativa para GSTT1 e o DNA do EBV foi negativo na margem distal. Em três pacientes, o EBV-DNA foi negativo apenas na margem distal. Conclusão: este é o primeiro relato em que diferentes genótipos, infecção por EBV-DNA e H. pylori foram observados no mesmo paciente, indicando provável deleção desses genes em resposta à progressão tumoral e heterogeneidade intratumoral.

ABSTRACT Objective: to compare the polymorphism of the Glutathione S-transferase theta 1 (GSTT1) and Glutathione S-transferase mu 1 (GSTM1) genes from the tumor area with the proximal and distal margins of stomach specimens resected from patients with gastric cancer, and to investigate the presence of Epstein-Barr virus (EBV) DNA and Helicobacter pylori. Methods: we prospectively collected tissue specimens from the tumor area and from the proximal and distal resection margins of the stomachs of ten patients with gastric adenocarcinoma who underwent gastrectomy with D2 lymphadenectomy, and submitted these specimens to DNA extraction. We compared the tumor area with the proximal and distal margins of the resected stomachs for polymorphism of GSTT1 and GSTM1 genes and investigated the presence of EBV-DNA and H. pylori. We used the p53 exon 5 gene as an internal control of the multiplex PCR reaction. Results: in one patient, we detected null GSTT1 and GSTM1 genotypes in the tumor area, in contrast to the presence of both genes in the proximal and distal margins. We found EBV-DNA and H. pylori in the tumor area and also in the proximal and distal margins. In another patient, the proximal margin was negative for GSTT1, and EBV-DNA was negative in the distal margin. In three patients, EBV-DNA was negative only in the distal margin. Conclusion: this is the first report where different genotypes, EBV-DNA and H. pylori infection were observed in the same patient, indicating a probable deletion of these genes in response to tumor progression and intratumoral heterogeneity.

Human polyomavirus infection: Cytological and molecular diagnosis / Infecção pelo poliomavírus humano: diagnóstico citológico e molecular

Summary Few studies directly compare urinary cytology with molecular methods for detecting BK and JC polyomaviruses. Reactivation of BKV infection is the main risk factor for the development of nephropathy in immunocompromised individuals. The limitation of the cytological method can be attributed to the stage where the infected cell does not have specific and sufficient morphological characteristics for a conclusive diagnosis and can be easily interpreted as degenerative alteration. Moreover, morphologically, it is not possible to differentiate the two types of viruses. Polymerase chain reaction (PCR), not only is a sensitive method, but also allows differentiation of viral types without quantification, and therefore is not indicative of nephropathy. According to the American Society of Nephrology, real-time PCR would be the gold standard to indicate nephropathy because it allows quantifying the number of viral copies.

Resumo Poucos estudos comparam diretamente a citologia urinária com métodos moleculares para detecção de poliomavírus BK e JC. A reativação da infecção por BKV é o principal fator de risco para o desenvolvimento de nefropatia em indivíduos imunocomprometidos. A limitação do método citológico pode ser atribuída ao estágio em que a célula infectada não possui características morfológicas específicas e suficientes para um diagnóstico conclusivo, podendo ser facilmente interpretada como alteração degenerativa. Além do mais, morfologicamente, não é possível diferenciar os dois tipos virais. A reação em cadeia pela polimerase (PCR), além de ser um método sensível, permite diferenciar os tipos virais sem quantificá-los, não sendo, portanto, indicativa de nefropatia. Segundo a American Society of Nephrology, a PCR em tempo real seria o padrão-ouro para indicar nefropatia, pois permite quantificar o número de cópias virais.

Considerations about gastric cancer proteomics / Considerações sobre proteômica no câncer gástrico

A frequência de estudos moleculares visando a analisar os promotores de metilação de genes supressores de tumor e proteômica globais na carcinogênese gástrica está aumentando. No entanto, apenas alguns consideraram os diferentes tipos de células do estômago, a localização do tumor e a influência da infecção por Helicobacter pylori e pelo vírus Epstein-Barr (EBV). Diferenças moleculares relacionadas com áreas tumorais anatômicas e histológicas também foram recentemente descritas. Os autores propõem uma classificação molecular de câncer gástrico, dividindo-o em quatro subtipos: tumores positivos para o EBV; tumores microssatélite instáveis; tumores genomicamente estáveis e tumores com instabilidade cromossômica.

Colorectal cancer DNA methylation patterns from patients in Manaus, Brazil

BACKGROUND: DNA methylation is commonly linked with the silencing of the gene expression for many tumor suppressor genes. As such, determining DNA methylation patterns should aid, in times to come, in the diagnosis and personal treatment for various types of cancers. Here, we analyzed the methylation pattern from five colorectal cancer patients from the Amazon state in Brazil for four tumor suppressor genes, viz.: DAPK, CDH1, CDKN2A, and TIMP2 by employing a polymerase chain reaction (PCR) specific to methylation. Efforts in the study of colorectal cancer are fundamental as it is the third most of highest incidence in the world. RESULTS: Tumor biopsies were methylated in 1/5 (20 %), 2/5 (40 %), 4/5 (80 %), and 4/5 (80 %) for CDH1, CDKN2A, DAPK, and TIMP2 genes, respectively. The margin biopsies were methylated in 3/7 (43 %), 2/7 (28 %), 7/7 (100 %), and 6/7 (86 %) for CDH1, CDKN2A, DAPK, and TIMP2, respectively. CONCLUSIONS: Our findings showed DAPK and TIMP2 to be methylated in most samples from both tumor tissues and adjacent non-neoplastic margins; thus presenting distinct methylation patterns. This emphasizes the importance of better understanding of the relation of these patterns with cancer in the context of different populations.

The prevalence of human cytomegalovirus DNA in gliomas of Brazilian patients

Members of the Herpesviridae family have been implicated in a number of tumours in humans. At least 75% of the human population has had contact with cytomegalovirus (HCMV). In this work, we screened 75 Brazilian glioma biopsies for the presence of HCMV DNA sequences. HCMV DNA was detected in 36% (27/75) of the biopsies. It is possible that HCMV could be a co-factor in the evolution of brain tumours.

Association study of the Ile349val polymorphism of the gene ADH1C and alcohol dependence / Estudo sobre a associação entre o polimorfismo Ile349Val do gene ADH1C e a dependência alcoólica

OBJECTIVE: The aim of this study was to investigate the polymorphism Ile349Val of the enzyme alcohol dehydrogenase ADH1C gene among individuals with alcohol dependence syndrome (ADS) attending Alcoholics Anonymous (AA) meetings. METHODS: A total of 120 subjects residing in Rio de Janeiro city participated in this study. Subjects were divided into two groups: a group consisting of 54 individuals from the ADS group and 66 individuals that declared not having any alcohol dependence (control group). DNA was extracted from mouth epithelial cells by phenol-chloroform method and further submitted to amplification by polymerase chain reaction (PCR). RESULTS: Our results did not show differences between the genotypes of control individuals and ADS subjects. Nevertheless, we found increased rates of alcoholism in families of ADS subjects as compared to controls. CONCLUSIONS: Our results did not show any genotype difference on the ADH1C gene when control and AA genotypes are compared.

OBJETIVO: Investigar o polimorfismo Ile349Val do gene ADH1C da enzima álcool desidrogenase e a dependência de álcool em indivíduos frequentadores dos Alcoólicos Anônimos (AA). MÉTODOS: Um total de 120 pessoas residentes na cidade do Rio de Janeiro foi dividido em dois grupos: o primeiro foi formado por 54 pessoas com síndrome de dependência do álcool (SDA) pertencentes ao grupo dos AA. O segundo, com 66 pessoas, foi formado por indivíduos que descreveram não serem dependentes de álcool (grupo controle). O DNA foi extraído de células da mucosa oral utilizando-se a técnica do fenol-clorofórmio e posteriormente amplificado pela reação em cadeia pela polimerase (PCR). RESULTADOS: Nossos resultados não mostraram diferenças entre o genótipo dos indivíduos controle e aqueles do grupo SDA. A análise, entretanto, demonstrou uma significativa relação entre o grupo SDA e o histórico familiar de alcoolismo. CONCLUSÕES: Em nossos resultados não encontramos diferenças quanto ao genótipo ADH1C em indivíduos com SDA e controles.

Infecção oral pelo HPV e lesões epiteliais proliferativas associadas / HPV oral infection and proliferative epithelial associated lesions

Os papilomavírus humanos (HPVs) pertencem à família Papillomaviridae e seu ciclo de vida é diretamente ligado à diferenciação das células epiteliais do hospedeiro. Possuem seis genes que se expressam precocemente e dois genes que se expressam tardiamente, sendo denominados respectivamente E (early) e L (late). O ácido desoxirribonucleico (DNA) viral dentro da célula do hospedeiro pode assumir duas formas: epissomal e integrada. O HPV tem como alvo as células basais de epitélios escamosos, em particular da área genital, onde está associado ao carcinoma da cérvice uterina. Na boca, o HPV está associado a papiloma escamoso oral, condiloma acuminado, verruga vulgar e hiperplasia epitelial focal. Entretanto, seu papel na carcinogênese oral é ainda controverso, sendo também identificado como agente etiológico de alguns carcinomas de células escamosas de cabeça e pescoço. A infecção pelo HPV pode agir sinergicamente com agentes carcinogênicos, como o tabaco e o álcool. Pelo menos 150 subtipos diferentes de HPV já foram identificados, sendo que 25 têm sido detectados em lesões orais. Considerando a relevância do tema para a melhor compreensão da infecção oral pelo HPV, o objetivo desta atualização é rever os aspectos relevantes da biologia do HPV, com ênfase na relação HPV-ceratinócitos, e a importância dos dados clínicos e histopatológicos na definição diagnóstica das lesões orais possivelmente associadas ao HPV.

Papillomaviruses belong to the family Papillomaviridae and their life cycle is directly linked to the differentiation of host epithelial cells. They have six genes that are expressed earlier and two genes that are expressed later in their life cycle, named respectively E (early) and L (late). Host cell viral DNA can take two forms: episomal and integrated. The human papillomavirus (HPV) targets the basal cells of squamous epithelia, particularly from the genital area, which is associated with uterine cervix carcinoma. In the oral area HPV is associated with oral squamous papilloma, condyloma acuminatum, verruca vulgaris, and focal epithelial hyperplasia. However, its role in oral carcinogenesis is still controversial. Moreover, it has identified as an etiological agent of some head and neck squamous cell carcinomas. HPV infection may act synergistically with carcinogens such as tobacco and alcohol. At least 150 different subtypes of HPV have been identified, of which 25 types have been detected in oral lesions. Considering the relevance of the topic for better understanding of HPV oral infection, the objective of this update is to review relevant aspects of HPV biology, with emphasis on HPV-keratinocytes relationship and the importance of clinical and histopathological aspects in the diagnosis of oral lesions possibly associated with HPV.

A frequência do HPV na mucosa oral normal de indivíduos sadios por meio da PCR / The frequency of human papillomavirus findings in normal oral mucosa of healthy people by PCR

Os papilomavírus humanos (HPV) são DNA vírus pertencentes à família papilomaviridae com grupos de baixo e alto risco que infectam a pele e a mucosa podendo induzir a formação de tumores epiteliais benignos e malignos. Na mucosa oral, estes vírus têm sido associados a papilomas orais, hiperplasias epiteliais focais, leucoplasias e neoplasias orais. Objetivo: Estudar a frequência do HPV em mucosa oral de indivíduos normais. Material e método: Trabalho prospectivo em coorte transversal. Participaram desse estudo 100 indivíduos voluntários, faixa etária de 20 a 31 anos, estudantes universitários, sem história, queixas ou lesões visíveis ao exame físico de cavidade oral e orofaringe. Foram submetidos a questionário com perguntas referentes à epidemiologia da infecção pelo HPV. Foi colhido material de mucosa oral por raspado com escova e analisado pelo PCR. Resultados: Os resultados mostraram ausência de HPV em todas as amostras. Conclusão: Parece ter havido participação do alto nível socioeconômico com alimentação rica em carotenoides e vitamina C, baixo consumo tabágico e etílico e comportamento heterossexual predominantemente monogâmico com uso regular de preservativos.

The human papillomavirus (HPV) is a DNA virus, which belongs to papillomaviridae family, being of low and high risk, which infect the skin and mucous membranes and can induce benign and malign tumor formation. In the oral mucosa they have been associated with oral papilloma, focal epithelial hyperplasia, leucoplakia and oral neoplasia. AIM: to study the frequency of HPV finding in oral mucosa of normal people. Materials and methods: Prospective study, cross-sectional cohort. One hundred volunteers, young adults, healthy, aged between 20 and 31 years, university students with no history, no complains, without oral or oropharyngeal lesions. They were submitted to a questionnaire with questions regarding HPV infection epidemiology. The samples were harvested by brushing and analyzed by PCR. Results: The results were negative for HPV in all samples. Conclusion: It seems we had high social and economical class individuals, with nutrition rich in carotenoyds and vitamin C, low smoking and alcohol consumption and heterosexual habits with predominant monogamy and regular use of condoms.

Metodologia para estudo do polimorfismo do gene da enzima álcool desidrogenase / Methodology to study the polymorphism of alcohol dehydrogenase gene

As principais enzimas responsáveis pelo metabolismo do álcool são a álcool desidrogenase (ADH) e aldeído desidrogenase (ALDH). EsSas enzimas estão presentes em várias formas e são codificadas por diferentes genes. Alguns desses genes apresentam polimorfismos, e as enzimas codificadas por eles podem apresentar diferenças quanto à eficiência metabólica em relação ao álcool e ao aldeído acético. EsSa variação tem se mostrado um fator que influencia a quantidade de álcool ingerido e o risco no aumento de abuso e dependência ao álcool. Neste trabalho, nós descrevemos um método que permite estudar o polimorfismo de um dos genes da enzima álcool desidrogenase, o gene ADH1C. O DNA foi isolado de doadores e o polimorfismo foi determinado pela reação em cadeia pela polimerase (PCR). Nossos resultados confirmam a viabilidade da técnica por nós descrita para o estudo do polimorfismo do gene ADH1C.

Máquina de agrupamento por elipsóide: uma linha de frente para auxiliar no diagnóstico de doenças / Ellipsoid clustering machine: a front line to aid in disease diagnosis

Este estudo apresenta nova estratégia de inferência direcionada a detectar presença de doenças em amostras biológicas. Diferencialmente dos métodos existentes, esta técnica é aplicável quando o número de patologias e as mesmas são desconhecidos. Esta é exemplificada através de software que denominamos "Máquina de Agrupamento por Elipsóide", do inglês, Ellipsoid Clustering Machine (ECM). O mesmo identifica regiões conservadas em perfis proteômicos obtidos por espectrometria de massa de amostras biológicas de indivíduos controles e estima limites para classifica- ção baseando-se na variância da expressão protéica. O software também pode ser utilizado para inspeção visual de reprodutibilidade de dados. O ECM foi avaliado utilizando perfis protéicos do soro de pacientes com a doença de Hodgkin e de indivíduos controle. De acordo com a validação cruzada leave-one-out, o ECM separou corretamente os grupos se baseando apenas na informação de quatro picos espectrais selecionados. Este trabalho descreve o algoritmo e apresenta imagens de modelos 3D representativos da separação. O software está disponível na página do projeto na internet junto com modelos interativos e uma animação demonstrando o método.