Navegando por Assunto "Oncogenes"

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Acesso aberto (Open Access)
Associação do perfil de acetilação lenta do gene NAT2 na susceptibilidade ao câncer, na Região Norte do Brasil
(Universidade Federal do Pará, 2013-04-10) FERNANDES, Marianne Rodrigues; SANTOS, Ney Pereira Carneiro dos; http://lattes.cnpq.br/1290427033107137; BURBANO, Rommel Mario Rodriguéz; http://lattes.cnpq.br/4362051219348099
Objectives: The N-acetyltransferase 2 (NAT2) gene is a marker for the study of interindividual susceptibility to develop malignant neoplasms, once the enzyme NAT2 takes part in the metabolism of carcinogenic agents and the single nucleotide polymorphism (SNP) of its gene produces enzymes with different activities, leading to either slow or fast acetylation of xenobiotics. The purpose of this study was to investigate a possible association between the NAT2 gene SNPS and susceptibility to the involvement of gastric adenocarcinoma or invasive ductal carcinoma of the breast in patients of northern Brazil. Methods: Five polymorphisms of great importance for defining the metabolism profile of enzyme NAT2 (C282T, T341C, C481T, A803G and G857A) were investigated by direct sequencing of 986 base pairs, amplified in two PCR reactions, totalizing 133 patients with neoplasms (63 with Gastric Cancer-GC and 70 with Breast Cancer-BC) and 89 Control subjects. In order to avoid spurious interpretations resulting from the population substructure, we used a panei with 48 ancestry informative markers (AIM). Results: We found statistical differences for African and European parental contribution when compared between the Cancer and Control groups; a higher African contribution was detected in the study group with Cancer and, in the control group, it was detected a higher European contribution (p<0.001). Dominating polymorph genotypes C282T (TT + CT) showed significant association (p<0.001; OR 3.076; Cl 95% 1.664-5.687) for susceptibility to the different forms of Cancer investigated. A significant association of slow and fast acetylation profile with the susceptibility to develop the investigated neoplasms was noticed (p=0.010; OR 3.054; Cl 95% 1.303-7.159) and (p= 0.041; OR 0.527 Cl 95% 0.280-0.973) clearly showing that individuais with slow acetylator profile showed a risk of developing neoplasms increased to up to three times when compared to Control subjects. Conclusions: Ancestry genomic control was effectively important for this investigation and enabled the control of the ancestry effect on the association of NAT2 gene for susceptibility to cancer. In this study, it was possible to prove the strong influence of xenobiotics slow acetylation profile on the susceptibility to GC and BC.
Acesso aberto (Open Access)
Cytogenetic characterization and evaluation of c-MYC gene amplification in PG100, a new Brazilian gastric cancer cell line
(2010-08) RIBEIRO, Helem Ferreira; ALCÂNTARA, Diego Di Felipe Ávila; MATOS, Leomá Albuquerque; SOUSA, João Marcelo de Castro e; LEAL, Mariana Ferreira; SMITH, Marília de Arruda Cardoso; BURBANO, Rommel Mario Rodriguéz; BAHIA, Marcelo de Oliveira
Gastric cancer is the fourth most frequent type of cancer and the second cause of cancer mortality worldwide. The genetic alterations described so far for gastric carcinomas include amplifications and mutations of the c-ERBB2, KRAS, MET, TP53, and c-MYC genes. Chromosomal instability described for gastric cancer includes gains and losses of whole chromosomes or parts of them and these events might lead to oncogene overexpression, showing the need for a better understanding of the cytogenetic aspects of this neoplasia. Very few gastric carcinoma cell lines have been isolated. The establishment and characterization of the biological properties of gastric cancer cell lines is a powerful tool to gather information about the evolution of this malignancy, and also to test new therapeutic approaches. The present study characterized cytogenetically PG100, the first commercially available gastric cancer cell line derived from a Brazilian patient who had a gastric adenocarcinoma, using GTG banding and fluorescent in situ hybridization to determine MYC amplification. Twenty metaphases were karyotyped; 19 (95%) of them presented chromosome 8 trisomy, where the MYC gene is located, and 17 (85%) presented a deletion in the 17p region, where the TP53 is located. These are common findings for gastric carcinomas, validating PG100 as an experimental model for this neoplasia. Eighty-six percent of 200 cells analyzed by fluorescent in situ hybridization presented MYC overexpression. Less frequent findings, such as 5p deletions and trisomy 16, open new perspectives for the study of this tumor.