Gastric cancer (GC) is a multifactorial disease with a high mortality rate in Brazil and worldwide. This work aimed to evaluate single nucleotide polymorphisms (SNP) rs1695, in the Glutathione S-Transferase Pi (GSTP1) gene in GC samples by comparative analysis Specific PCR - ASP and Dideoxy Single Allele-Specific PCR - DSASP methods. The DSASP is the proposed new method for allelic discrimination. This work analyzed 60 GC samples, 26 diffuse and 34 intestinal types. The SNP rs1695 of the GSTP1 gene was significantly associated with GC analyzed by DSASP method (χ2 = 9.7, P < 0.05). A comparative analysis of the data obtained from both methods did not differ significantly (χ2 = 0.08, P > 0.05). These results suggest that the SNP rs1695 of the GSTP1 gene was a risk factor associated with gastric carcinogens is and the DSASP method was a new successfully low-cost strategy to study allelic discrimination.

Abstract Background Tumor necrosis factor plays a critical role in the pathogenesis of gastric diseases such as gastric cancer, and an abnormal inflammatory response has frequently been observed in dyspeptic patients. Helicobacter pylori infection can induce a gastric mucosal inflammatory response that may be influenced by -308 (G > A) polymorphisms and gene expression of theTNF-α gene. Methods One hundred and thirty-four gastric biopsy samples were collected from patients of both genders (61♂ and 73♀, mean age 40.3 ± 24.2 years) with gastric symptoms. The -308 (G > A) polymorphism of TNF-α was characterized using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). The expression level was measured using real-time PCR, and relative quantification (RQ) was calculated using the comparative CT method (2-ΔΔCT). Results The analysis revealed an increase in TNF-α gene expression in patients with gastritis; on the other hand, no statistical differences were observed in patients with gastric cancer. In addition, no association was found among -308 polymorphism genotypes, virulence markers, or TNF-α gene expression. Conclusions Helicobacter pylori induces a large increase in TNF-α expression in patients with gastritis, regardless of tissue inflammation, but after the tissue becomes neoplastic, the presence of bacteria did not influence expression. These results suggest that the TNF-α pathway may play an important role in the progression from gastritis to gastric cancer

BACKGROUND: Recently, the importance of cytogenetics has grown in the diagnosis, prognosis and treatment of leukemias and myelodysplastic syndromes. 5-azacytidine is a drug that has well-known cytogenetical effects and is approved in the treatment of myelodysplastic syndromes. To date, no studies have been performed to evaluate the impact of 5-azacytidine on the chromosomes of patients with hematological neoplasias. This study aimed to investigate the effects of 5-azacytidine on chromosomes of patients with different hematological malignancies using G-band analyses to identify possible cytogenetical alterations. METHODS: The peripheral blood of 18 patients with hematological malignancies and 18 controls was collected in heparinized tubes. 5-azacytidine was added, at a final concentration of 10-5M, to cultures 7 hours prior to harvest. RESULTS: Uncoiled centromeric/pericentromeric heterochromatin of chromosomes-1, 9 and 16 occurred more frequently in the patients than in controls. This higher frequency of uncoiled heterochromatin was statistically significant (p-value = 0.004) for chromosome-9. Conversely, we observed that the fragile site at 19q13 was more frequent in controls (p-value = 0.0468). CONCLUSIONS: The results of this study suggest that satellite sequences, located in the heterochromatin of chromosome-9, are hypomethylated in hematological malignancies. This hypomethylation may contribute to the disease, activating transposable elements and/or promoting genomic instability, enabling the loss of heterozygosity of important tumor suppressor genes. An investigation of the 19q13 region may help to understand whether or not the predominant occurrence of the fragile site at 19q13 in controls is due to hypermethylation of this region.

An inflammatory process has been involved in numerous neurodegenerative disorders such as Parkinson's disease, stroke and Alzheimer's disease (AD). In AD, the inflammatory response is mainly located in the vicinity of amyloid plaques. Cytokines, such as interleukin-8 (IL-8) and interleukin-1α (IL-1α), have been clearly involved in this inflammatory process. Polymorphisms of several interleukin genes have been correlated to the risk of developing AD. The present study investigated the association of AD with polymorphisms IL-8 -251T > A (rs4073) and IL-1α-889C > T (rs1800587) and the interactive effect of both, adjusted by the Apolipoprotein E genotype. 199 blood samples from patients with AD, 146 healthy elderly controls and 95 healthy young controls were obtained. DNA samples were isolated from blood cells, and the PCR-RFLP method was used for genotyping. The genotype distributions of polymorphisms IL-8, IL-1α and APOE were as expected under Hardy-Weinberg equilibrium. The allele frequencies did not differ significantly among the three groups tested. As expected, the APOE4 allele was strongly associated with AD (p < 0.001). No association of AD with either the IL-1α or the IL-8 polymorphism was observed, nor was any interactive effect between both polymorphisms. These results confirm previous studies in other populations, in which polymorphisms IL-8 -251T > A and IL-1α-889C > T were not found to be risk factors for AD.

Helicobacter pylori is an important human pathogen that causes chronic gastritis and is associated with the development of peptic ulcer disease and gastric malignancies. The oral cavity has been implicated as a potential H. pylori reservoir and may therefore be involved in the reinfection of the stomach, which can sometimes occur following treatment of an H. pylori infection. The objectives of this paper were (i) to determine the presence of H. pylori in the oral cavity and (ii) to examine the relationship between oral H. pylori and subsequent gastritis. Gastric biopsies, saliva samples and dental plaques were obtained from 78 dyspeptic adults. DNA was extracted and evaluated for the presence of H. pylori using polymerase chain reaction and Southern blotting methods. Persons with gastritis were frequently positive for H. pylori in their stomachs (p < 0.0001) and there was a statistically significant correlation between the presence of H. pylori in gastric biopsies and the oral cavity (p < 0.0001). Our results suggest a relationship between gastric infection and the presence of this bacterium in the oral cavity. Despite this, H. pylori were present in the oral cavity with variable distribution between saliva and dental plaques, suggesting the existence of a reservoir for the species and a potential association with gastric reinfection.

The presence of human papillomavirus (HPV) was evaluated in 65 samples of prostate tumours and six samples of prostates with benign prostatic hyperplasia from individuals from Northern Brazil. We used a highly sensitive test, the Linear Array HPV Genotyping Test, to detect 37 high and low-risk HPV types. In this study, only 3% of tumour samples showed HPV infection. Our findings support the conclusion that, despite the high incidence of HPV infection in the geographic regions studied, HPV was not associated with a higher risk of prostate cancer. To our knowledge, this is the first study evaluating the frequency of HPV detection in prostatic tissue of individuals from Brazil.

Gastric cancer is one of the most common malignancies. DNA methylation is implicated in DNA mismatch repair genes deficiency. In the present study, we evaluated the methylation status of MLH1, MSH2, MSH6 and PMS2 in 20 diffuse- and 26 intestinal-type gastric cancer samples and 20 normal gastric mucosal of gastric cancer patients from Northern Brazil. We found that none of the nonneoplastic samples showed methylation of any gene promoter and 50% of gastric cancer samples showed at least one methylated gene promoter. Methylation frequencies of MLH1, MSH2, MSH6 and PMS2 promoter were 21.74%, 17.39%, 0% and 28.26% respectively in gastric cancer samples. MLH1 and PMS2 methylation were associated with neoplastic samples compared to nonneoplastic ones. PMS2 methylation was associated with diffuse-and intestinal-type cancer compared with normal controls. Intestinal-type cancer showed significant association with MLH1 methylation. Diffuse-type cancer was significantly associated with MSH2 methylation. Our findings show differential gene methylation in tumoral tissue, which allows us to conclude that methylation is associated with gastric carcinogenesis. Methylation of mismatch repair genes was associated with gastric carcinogenesis and may be a helpful tool for diagnosis, prognosis and therapies. However, MSH6 does not seem to be regulated by methylation in our samples.

Gastric cancer is the forth malignancy in frequency in the world. In the northern Brazil is the second neoplasia most frequent in males and the third most frequent in females. Genetic and epigenetic alterations are evolved on gastric carcinogenesis and DNA methylation is the epigenetic alteration better studied. We analyzed de novo DNA methyltransferases methylation pattern and its association with RUNX3 gene methylation pattern in Brazilian samples of intestinal-type and diffuse-type of gastric cancer. PCR methylation specific was used to evaluate DNA methylation pattern. Sixty-six samples were studied in this work. Only the gene RUNX3 presented altered methylation pattern, being methylated in 38.5% of gastric cancer intestinal-type samples and in 70% of gastric cancer diffuse-type samples and, by this reason, it should be evolved in the genesis of this neoplasia. There was a statistically significant difference among diffuse-type and intestinal-type samples (p=0.0418) and among normal and tumour tissues (p<0.0001) for RUNX3 gene but not to DNMT3A, DNMT3B e DNMT3 genes on CpG islands analyzed. Alteration of RUNX3 methylation pattern is not associated to de novo alteration of DNA methyltransferases methylation pattern on studied regionsTherefore, it becomes necessary a better comprehension of this phenomenon on gastric carcinogenesis

El cáncer gástrico es la cuarta patología más frecuente en el mundo. En el norte del Brasil, es la segunda neoplasia más frecuente en hombres y la tercera en mujeres. Alteraciones genéticas y epigenéticas relacionadas con la carcinogénesis gástrica y la metilación del DNA son las alteraciones epigenéticas mejor estudiadas. En este trabajo, analizamos el estado de novo de metilación de genes DNA metiltransferases y su asociación con el estado de metilación del gen RUNX3 en muestras de individuos brasileños con cáncer gástrico de los tipos intestinal y difuso. Fue usada la Reacción en Cadena de la Polimerasa (PCR), metilación específica, para analizar el estado de metilación del DNA. Fueron estudiados 66 tejidos tumorales. Solamente el gen RUNX3 presentó un estado de metilación alterado, estuvo metilado en 38,5% de las muestras de cáncer gástrico tipo intestinal y en 70% de muestras de cáncer gástrico tipo difuso, lo que sugiere que estaría relacionado con la génesis de esta neoplasia. Hubo una diferencia estadística significativa entre muestras de los tipos difuso e intestinal (p=0.0418) y entre tejidos normal y tumoral (p<0.0001)parael gen RUNX3. Esta asociación no fue encontrada para los genes DNMT3A, DNMT3B y DNMT3 en las islas CpG analizadas. Alteraciones del estado de metilación de RUNX3 no están asociadas con alteraciones de novo de genes DNA metiltransferases. De esta forma se hace necesaria una mejor comprensión de este fenómeno en la carcinogénesis gástrica

In the current carcinogenesis models, the occurrence of increasing mutations and selection mechanisms favoring cell survival and higher proliferation rates are taken into account. Epigenetic mechanisms, among which DNA methylation stands out, also take part in oncogenesis. The characteristic of tumor cells that allows the increase of mutations is named genetic instability, encompassing two mechanisms: microsatellite instability, characterized by nucleotide alterations with errors in the DNA repair systems; and chromosomal instability, represented by aberrations occurring in large chromosome segments. Carcinomas are characterized by complex cytogenetic alterations and large gene amalgamations. Telomeric alterations, inadequately repaired DNA breaks, and deficiencies in the mitotic spindle checking systems are events capable of generating the chromosomal instability and aneuploidy which characterize more aggressive neoplasias. A better understanding of the chromosomal instability mechanisms can show the way towards a clinical utilization of such information, like developing more adequate therapeutic strategies, targeted at specific sites involved in the malignization process

Los modelos actuales de carcinogénesis consideran la ocurrencia de mutaciones crecientes y mecanismos selectivos, favoreciendo la sobrevivencia y proliferación celular aumentada. Mecanismos epigenéticos también participan en la oncogénesis, destacando la metilación del DNA. La característica de las células tumorales que permite el aumento de la ocurrencia de mutaciones es denominada inestabilidad genética, donde son identificados dos mecanismos: inestabilidad de microsatélites, caracterizada por alteraciones nucleotídicas con errores en los sistemas de reparación del DNA; inestabilidad cromosómica, en la cual las aberraciones suceden en grandes segmentos cromosómicos. Los carcinomas son caracterizados por alteraciones citogenéticas complejas y grandes mezclas génicas. Alteraciones teloméricas, quiebres de DNA reparados inadecuadamente y deficiencia en los sistemas de chequeo del huso mitótico, son eventos capaces de generar inestabilidad cromosómica y aneuploidía que caracterizan estas neoplasias más agresivas. El conocimiento de los mecanismos que provocan la inestabilidad cromosómica puede permitir la utilización clínica de información en el desarrollo de estrategias terapéuticas más adecuadas, dirigidas a puntos específicos involucrados en procesos de malignización

Helicobacter pylori is a spiral-shaped Gram-negative bacterium. It colonizes the gastric mucosa of humans and persists for decades if not treated. Helicobacter pylori infection affects more than half of the world's population and invariably results in chronic gastritis. The cagA gene is present in about 60 to 70% of H. pylori strains; it encodes a high-molecular-weight protein (120 to 140 kDa) and several investigators have noted a correlation between strains that possess cagA and the severity of gastric mucosal inflammation. We examined the relation between cagA status in H. pylori strains and chronic gastritis with inflammatory processes in children from Marília, São Paulo, Brazil. One-hundred-twenty-one children were analyzed histopathologically and by polymerase chain reaction (PCR) to detect H. pylori and cagA. We then looked for an association between cagA presence and inflammatory infiltration. Using histology and PCR, we found 47% H. pylori positive infection; 29 children were diagnosed with chronic gastritis, while 28 showed normal mucosa by histopathological analysis. CagA presence was genotyped in both groups, and an inflammatory infiltrate was studied in all infected children with chronic gastritis. We found cagA strains in 20 of 29 (69%) children with chronic gastritis and 18 of 28 (64%) with normal mucosa, demonstrating a strong relationship between the strains and the inflammatory process. We found a positive association between an inflammatory process associated with H. pylori of cagA+ strains and chronic gastritis development.

A linhagem celular Hep-2 é formada por células de carcinoma da laringe e é muito utilizada em modelos de carcinogênese e mutagenêse. Para avaliar o potencial proliferativo desta linhagem, desenvolvemos uma metodologia citogenética (técnica do sobrenadante) para obtenção de metáfases a partir de células que, ao entrarem em mitose, perdem adesão celular, ficando em suspensão no meio de cultura. Através deste procedimento, foram contadas 2000 células, correspondendo a um índice mitótico (IM) de 22.2% . Apesar de o IM obtido por esta técnica não ter sido estatisticamente diferente do IM obtido por outras metodologias citogenéticas clássicas, a técnica do sobrenadante é vantajosa porque elimina o uso de alguns reagentes utilizados na obtenção de metáfases e também diminui o consumo de reagentes de manutenção desta linhagem.

The Hep-2 cell line is derived from laryngeal carcinoma cells and is often utilized as a model in carcinogenesis and mutagenesis tests. To evaluate the proliferative potential of this line, we developed a cytogenetic methodology (drifter technique) to obtain metaphases from cells that loose cellular adhesion when they underwent mitosis in culture. By this procedure, 2000 cells were counted, resulting in a mitotic index (MI) of 22.2%. Although this MI was not statistically different from the one obtained using either a classical cytogenetic method or a cell synchronization technique, the drifter technique has the advantage of not requiring the use of some reagents for the obtention of metaphases and also of diminishing the consumption of maintenance reagents for this cell line.

Chromosome X loss associated with advancing age in women is well stablished in cytogenetics. However, genetic factors involved in this chromosome loss or no disjunction are poorly understood. Apolipoproteins have been associated with chromosome syndromes, such as Trisomy 21 and 18 and their participation in chromosome segregation have been suggested. Apolipoprotein A-IV:360 polymorphism has been associated with cardiovascular diseases, in our population. Twenty four old women, aged 72 to 87 years old selected according to the presence or absence of allele 2 (HIS) were investigated in relation to chromosome X loss. Cytogenetic analysis was performed in interphase lymphocyte nuclei by means of FISH ( Fluorescence In Situ Hibridization) using X centromeric DNA probe. DNA was isolated from blood cells amplified by PCR and digested with Fnu4HI. A higher significant proportion of cells with X chromosome loss was observed in elderly women with allele 2 (HIS) .These results indicate the participation of apolipoprotein A-IV:360 polymorphism in chromosome segregation. The involved mechanisms could be related to oxidative damage related to microcirculation abnormalities and cell death. The biological role of apolipoprotein A-IV on chromosome segregation needs to be further investigated

La pérdida del cromosoma X en mujeres, asociada a la edad avanzada, es un fenómeno ya reconocido hace décadas. Los factores genéticos que llevan a esta pérdida o a la no-disyunción cromosómica, son poco conocidos. Polimorfismos de apolipoproteínas fueron asociados a la ocurrencia de síndromes cromosómicos como las trisomías del 18 y 21 y fue sugerida su participación en la segregación cromosómica. Polimorfismos de la apolipoproteína AIV:360 fueron asociados a molestias cardiovasculares en la población brasileña.Veinticuatro mujeres entre 72 a 87 años, fueron seleccionadas para estudiar la presencia o ausencia del alelo 2 (HIS) y analizar la pérdida del cromosoma X. El análisis citogenético fue realizado en núcleos interfásicos de cultivos de linfocitos por técnica de hibridación in situ con sonda fluorescente centromérica del cromosoma X. El análisis genotípico fue realizado a partir de ADN extraído de la sangre, amplificado por PCR y digerido por la enzima de restricción Fnu4HI. Se observó una proporción significantemente mayor de células con la pérdida del cromosoma X, en mujeres con alelo 2 (HIS). Estos resultados indican la participación del gen de la ApoA-IV en la no-disyunción cromosómica. Los mecanismos de su actuación pueden estar relacionados a daños oxidativos producto de alteraciones en la microcirculación e inducción de muerte celular. La comprensión de este mecanismo todavía necesita de mayor investigación

O artigo apresenta uma revisão sucinta dos aspectos genéticos da doença de Alzheimer e da metodologia empregada. Três genes distintos foram responsabilizados pela afecção até o momento: o da APP<FONT FACE="Symbol">-</FONT> responsável pela substância precursora da b-amilóide, a qual se deposita intensamente no cérebro dos afetados e está associada ao quadro demencial <FONT FACE="Symbol">-</FONT>, o gene da presenilina 1 (PS1) e o da presenilina 2 (PS2), proteínas de membrana celular. O gene da PS1 é responsável por cerca de 40% dos casos familiares e de acometimento precoce da DA . Os genes da ApoE4, da a-2-macroglobulina e da catepsina D, envolvidos no metabolismo da b-amilóide, foram caracterizados como fatores de risco para a DA. O gene da ApoE4 é fator de risco em cerca de 50% dos casos de DA esporádicos e de acometimento tardio. Muitos outros genes foram ainda associados à DA e são apresentados brevemente. São discutidas a conduta <FONT FACE="Symbol">-</FONT> quanto ao aconselhamento genético para familiares de afetados <FONT FACE="Symbol">-</FONT> e a utilização de diagnóstico molecular na predisposição genética à afecção. É apresentado como mecanismo comum às síndromes progeróides genéticas, como a DA, a alteração da atividade dos genes ribossômicos.

This paper concisely reviews the genetics of Alzheimer Disease (AD). So far, three different genes have been implicated in AD. Specifically, the gene that codes for APP <FONT FACE="Symbol">-</FONT> the amyloid beta precursor protein, which is associated to dementia through intense brain deposition <FONT FACE="Symbol">-</FONT> the presenilin 1 gene (PS1) and the presenilin 2 gene (PS2). Both presenilin genes code for cellular membrane proteins and PS1 are responsible for approximately 40% of the early-onset familial cases. Genes that code for ApoE4, alpha-2 macroglobulin and cathepsin D, which are all involved in APP metabolism, have been considered as risk factors for AD. The ApoE4 gene is a risk factor in about 50% of the AD sporadic and late-onset cases. Several other genes that have been associated to AD are briefly discussed. Different strategies for genetic counseling of relatives are considered, and finally, ribosomal gene alterations are discussed as possible mechanisms underlying genetic progeroid syndromes such as AD.