Ana Hatagima

Meta-analysis and pooled analysis of GSTM1 and CYP1A1 polymorphisms and oral and pharyngeal cancers: A HuGE-GSEC review

The association of GSTM1 and CYP1A1 polymorphisms and oral and pharyngeal cancers was assessed through a meta-analysis of published case-control studies and a pooled analysis of both published and unpublished case-control studies from the Genetic Susceptibility to Environmental Carcinogens database (http://www.upci.upmc.edu/research/ccps/ccontrol/index.html). Thirty publications used in the meta-analysis included a total of 7783 subjects (3177 cases and 4606 controls); 21 datasets, 9397 subjects (3130 cases and 6267 controls) were included in the pooled analysis. The GSTM1 deletion was 2-fold more likely to occur in African American and African cases than controls (odds ratio: 1.7, 95% confidence interval: 0.9–3.3), although this was not observed among whites (odds ratio: 1.0, 95% confidence interval: 0.9–1.1). The meta-analysis and pooled analysis showed a significant association between oral and pharyngeal cancer and the CYP1A1 MspI homozygous variant (meta-ORm2/m2: 1.9, 95% confidence interval: 1.4–2.7; Pooled ORm2m2: 2.0, 95% confidence interval: 1.3–3.1; ORm1m2 or [infi]m2m2: 1.3, 95% confidence interval: 1.1–1.6). The association was present for the CYP1A1 (exon 7) polymorphism (ORVal/Val: 2.2, 95% confidence interval: 1.1–4.5) in ever smokers. A joint effect was observed for GSTM1 homozygous deletion and the CYP1A1 m1m2 variant on cancer risk. Our findings suggest that tobacco use and genetic factors play a significant role in oral and pharyngeal cancer.

Genetic polymorphisms and metabolism of endocrine disruptors in cancer susceptibility

Epidemiological studies have estimated that approximately 80% of all cancers are related to environmental factors. Individual cancer susceptibility can be the result of several host factors, including differences in metabolism, DNA repair, altered expression of tumor suppressor genes and proto-oncogenes, and nutritional status. Xenobiotic metabolism is the principal mechanism for maintaining homeostasis during the bodys exposure to xenobiotics. The balance of xenobiotic absorption and elimination rates in metabolism can be important in the prevention of DNA damage by chemical carcinogens. Thus the ability to metabolize and eliminate xenobiotics can be considered one of the bodys first protective mechanisms. Variability in individual metabolism has been related to the enzymatic polymorphisms involved in activation and detoxification of chemical carcinogens. This paper is a contemporary literature review on genetic polymorphisms involved in the metabolism of endocrine disruptors potentially related to cancer development.

Superoxide dismutase, catalase, glutathione peroxidase and gluthatione S-transferases M1 and T1 gene polymorphisms in three Brazilian population groups

Antioxidants such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX1) reduce the oxidation rates in the organism. Gluthatione S-transferases (GSTs) play a vital role in phase 2 of biotransformation of many substances. Variation in the expression of these enzymes suggests individual differences for the degree of antioxidant protection and geographical differences in the distribution of these variants. We described the distribution frequency of CAT (21A/T), SOD2 (Ala9Val), GPX1 (Pro198Leu), GSTM1 and GSTT1 polymorphisms in three Brazilian population groups: Kayabi Amerindians (n = 60), Kalunga Afro-descendants (n = 72), and an urban mixed population from Federal District (n = 162). Frequencies of the variants observed in Kalunga (18% to 58%) and Federal District (33% to 63%) were similar to those observed in Euro and Afro-descendants, while in Kayabi (3% to 68%), depending on the marker, frequencies were similar to the ones found in different ethnic groups. Except for SOD2 in all population groups studied here, and for GPX1 in Kalunga, the genotypic distributions were in accordance with Hardy-Weinberg Equilibrium. These data can clarify the contribution of different ethnicities in the formation of mixed populations, such as that of Brazil. Moreover, outcomes will be valuable resources for future functional studies and for genetic studies in specific populations. If these studies are designed to comprehensively explore the role of these genetic polymorphisms in the etiology of human diseases they may help to prevent inconsistent genotype-phenotype associations in pharmacogenetic studies.

Association between the MTHFR A1298C polymorphism and increased risk of acute myeloid leukemia in Brazilian children

Methylenetetrahydrofolate reductase (MTHFR) is an essential enzyme in the metabolism of folate. The presence of polymorphisms that reduce the activity of MTHFR has been linked to the multifactor process of development of acute leukemia. A case control study was conducted on Brazilian children in different regions of the country with the aim of investigating the role of MTHFR C677T and A1298C polymorphisms as risk factors in the development of acute myeloid leukemia (AML). We used the polymerase chain reaction restriction fragment length polymorphism method to genotyping 182 AML and 315 healthy individuals. The genotype 677 CT was associated with decreased risk [odds ratio (OR), 0.37; confidence interval (CI) 95%, 0.14 – 0.92], whereas 1298 AC genotype was linked with an increased risk [OR, 2.90; CI 95%, 1.26 – 6.71] of developing AML in non-white children. Further epidemiological study is needed to unravel the complex multiple gene-environment interactions in the role of the AML leukemogenesis.

Glutathione S-transferase M1 (GSTM1) polymorphism in two Brazilian populations

The distribution of GSTM1 phenotype frequencies was studied in two Brazilian samples composed of healthy and unrelated blood donors of both sexes ranging in age from 18 to 61 years. The first sample consisted of 658 individuals from Rio de Janeiro, and the second included 179 individuals from Brasilia. The GSTM1 phenotypes were detected using PCR reactions and subsequent digestion by the restriction enzyme HaeII. The GSTM1 null phenotype frequency was 46% and 49% for Rio de Janeiro and Brasilia samples, respectively. The GSTM1 phenotype distributions were not in agreement with Hardy-Weinberg equilibrium in either sample, c21 = 11.49 (P < 0.001) for Rio de Janeiro and c21 = 6.77 (P < 0.01) for Brasilia. This deviation from Hardy-Weinberg equilibrium may be due to factors such as selection, errors in the phenotype determination or incomplete panmixia of the Brazilian population, whose main racial components are Caucasians, Africans and Indians.

Polimorfismos do gene NRAMP1 em indivíduos com reações hansênicas, atendidos em dois Centros de Referência no Recife, nordeste do Brasil

INTRODUCTION: To investigate susceptibility to leprosy reactions, three polymorphisms of the natural resistance-associated macrophage protein (NRAMP1) gene were determined in 201 individuals who were attended at two reference centers in Recife, between 2007 and 2008. Of these, 100 were paucibacillary and 101 were multibacillary. METHODS: The 274C/T, D543N and 1729+55del4 polymorphisms of the NRAMP1 gene were determined using the technique of restriction fragment polymorphism on DNA extracted from peripheral blood. Allelic and genotypic frequencies were estimated by direct counting. RESULTS: The predominant genotypes were: CC (51.8%) for 274C/T; GG (86.6%) for D543N; and +-TGTG (59.9%) for 1729+55del4. The mutant genotype 274 TT predominated in negativity of the reverse reaction (p = 0.03) and in positivity of erythema nodosum leprosum (p = 0.04). CONCLUSIONS: Our results suggest that 274 C/T polymorphism of the NRAMP1 gene may aid in determining the susceptibility to type II reactions among leprosy patients.

Glutathione S-Transferase M1 (GSTM1) and T1 (GSTT1) Polymorphisms in a Brazilian Mixed Population

The GSTM1 and GSTT1 null genotype frequencies were significantly different between 658 nonblack and black healthy blood donors from a Brazilian mixed population (Rio de Janeiro). The GSTM1 phenotype distribution was not in Hardy–Weinberg equilibrium in either group, mainly because of an excess of the GSTM1*A/*B genotype.

Renin-angiotensin system: is it possible to identify hypertension susceptibility genes?

. Em que pese a inexistencia de um estudo de base populacional com representatividade nacional para HAS, indicadores de morbidade e mortalidade por doenca cerebrovascular podem mostrar, claramente, a relevância da HAS para a saude publica brasileira, uma vez que representa um fator de risco com expressiva forca de determinacao para doencas cardiovasculares

Distribution of glutathione S-transferase GSTM1 and GSTT1 null phenotypes in Brazilian Amerindians

The distribution of glutathione S-transferase (GST) GSTM1 and GSTT1 null phenotype frequencies in two Brazilian Amerindian tribes, the Munduruku tribe from Missao Cururu village (79 individuals) and the Kayabi tribe (41 individuals), was analyzed by polymerase chain reaction (PCR) amplification. The GST null phenotype frequencies for the Munduruku sample were 0% for GSTM1 and 27% for GSTT1 while for the Kayabi sample the null phenotype frequencies were 27% for GSTM1 and 29% for GSTT1. This is the first report of the absence of the GSTM1 null phenotype in any ethnic group.

Human glutathione S-transferase polymorphisms associated with prostate cancer in the Brazilian population

OBJECTIVE To evaluate the influence of polymorphisms in GSTA1, GSTM1, GSTT1, and GSTP1 in the risk of developing Prostate Cancer (PCa) in a population of Rio de Janeiro and compare the distribution of allele and genotype frequencies of the polymorphisms analyzed in the present study population with other regions in the country and different ethnic groups. MATERIALS AND METHODS We analyzed a sample of the Brazilian population, comprising 196 patients with PCa treated by the urology services of the Brazilian National Cancer Institute (INCA) and Mario Kroeff Hospital (HMK), and 208 male blood donors from the Clementino Fraga Filho Hospital, Federal University of Rio de Janeiro (UFRJ). The polymorphisms were determined in DNA, extracted from peripheral blood leucocytes using the Polymerase Chain Reaction and Restriction Fragment Length Polymorphism (PCR-RFLP). RESULTS Our results showed that the distribution of polymorphisms can vary significantly according to the Brazilian region and ethnic groups. The distribution of allele and genotype frequencies of the polymorphism GSTA1 was statistically different between cases and controls. Genotypes (A / B + B / B) were associated with protection (OR = 0.61, 95% CI = 0.40-0.92) for PCa in comparison to genotype A / A. CONCLUSION The distribution of genotype frequencies of the polymorphism GSTA1 was statistically different between the case and control groups (p = 0.023), and the presence of genotypes A / B and B / B suggests a protective role against the risk of PCa compared to genotype A / A. This is the first study that reports the genotypic frequency of this polymorphism and its association with PCa in a Brazilian population sample.