Methylation status of ANAPC1, CDKN2A and TP53 promoter genes in individuals with gastric cancer

Gastric cancer is the forth most frequent malignancy and the second most common cause of cancer death worldwide. DNA methylation is the most studied epigenetic alteration, occurring through a methyl radical addition to the cytosine base adjacent to guanine. Many tumor genes are inactivated by DNA methylation in gastric cancer. We evaluated the DNA methylation status of ANAPC1, CDKN2A and TP53 by methylation-specific PCR in 20 diffuse- and 26 intestinal-type gastric cancer samples and 20 normal gastric mucosa in individuals from Northern Brazil. All gastric cancer samples were advanced stage adenocarcinomas. Gastric samples were surgically obtained at the João de Barros Barreto University Hospital, State of Pará, and were stored at -80°C before DNA extraction. Patients had never been submitted to chemotherapy or radiotherapy, nor did they have any other diagnosed cancer. None of the gastric cancer samples presented methylated DNA sequences for ANAPC1 and TP53. CDKN2A methylation was not detected in any normal gastric mucosa; however, the CDKN2A promoter was methylated in 30.4% of gastric cancer samples, with 35% methylation in diffuse-type and 26.9% in intestinal-type cancers. CDKN2A methylation was associated with the carcinogenesis process for ~30% diffuse-type and intestinal-type compared to non-neoplastic samples. Thus, ANAPC1 and TP53 methylation was probably not implicated in gastric carcinogenesis in our samples. CDKN2A can be implicated in the carcinogenesis process of only a subset of gastric neoplasias.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FINEP/CT-INFRAFAEPAUniversidade Federal do Piauí Colegiado de BiomedicinaUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de MorfologiaUniversidade Federal do Pará Instituto de Ciências Biológicas Laboratório de Citogenética HumanaHospital João de Barros Barreto Serviço de CirurgiaInstituto de Investigaciones BiomedicasUniversidade de São Paulo Faculdade de Medicina de Ribeirão Preto Departamento de GenéticaUNIFESP, EPM, Depto. de MorfologiaFINEP/CT-INFRA: 0927-03SciEL

Prognostic and Predictive Significance of MYC and KRAS Alterations in Breast Cancer from Women Treated with Neoadjuvant Chemotherapy

Breast cancer is a complex disease, with heterogeneous clinical evolution. Several analyses have been performed to identify the risk factors for breast cancer progression and the patients who respond best to a specific treatment. We aimed to evaluate whether the hormone receptor expression, HER2 and MYC genes and their protein status, and KRAS codon 12 mutations may be prognostic or predictive biomarkers of breast cancer. Protein, gene and mutation status were concomitantly evaluated in 116 breast tumors from women who underwent neoadjuvant chemotherapy with doxorubicin plus cyclophosphamide. We observed that MYC expression was associated with luminal B and HER2 overexpression phenotypes compared to luminal A (p= 2.5 was a protective factor for chemotherapy resistance. On the other hand, age and grade 2 tumors were a risk factor. Additionally, luminal B, HER2 overexpression, and triple-negative tumors presented increased odds of being resistant to chemotherapy relative to luminal A tumors. Thus, breast tumors with KRAS codon 12 mutations seem to present a worse prognosis. Additionally, MYC amplification may help in the identification of tumors that are sensitive to doxorubicin plus cyclophosphamide treatment. If confirmed in a large set of samples, these markers may be useful for clinical stratification and prognosis.Fundacao Amazonia Paraense de Amparo a PesquisaConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Ophir Loyola Hosp, Mastol Unit, Belem, PA, BrazilUniversidade Federal de São Paulo, Dept Orthopaed & Traumatol, São Paulo, BrazilFed Univ Para, Inst Biol Sci, Human Cytogenet Lab, BR-66059 Belem, PA, BrazilHosp Univ La Paz, Res Unit Unidad Invest, Madrid, SpainFed Univ Para, Nucleu Res Oncol, Joao de Barros Barreto Univ Hosp, BR-66059 Belem, PA, BrazilUniv Fed Piaui, Dept Biomed, Parnaiba, PI, BrazilUniversidade Federal de São Paulo, Div Genet, Dept Morphol & Genet, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Orthopaed & Traumatol, São Paulo, BrazilUniversidade Federal de São Paulo, Div Genet, Dept Morphol & Genet, São Paulo, BrazilFundacao Amazonia Paraense de Amparo a Pesquisa: FAPESPA/PPSUS 247/2009Fundacao Amazonia Paraense de Amparo a Pesquisa: 300240/2009Web of Scienc

Occurrence of Helicobacter pylori and Epstein-Barr virus infection in endoscopic and gastric cancer patients from Northern Brazil

Background: Helicobacter pylori (HP) and Epstein-Barr virus (EBV) have been associated with cancer development. We evaluated the prevalence of HP, HP CagA(+) and EBV infection in gastric cancer (GC) samples from adults and in gastric tissues from patients who underwent upper endoscopy (UE).Methods: Samples from UE and GC were collected to investigate the presence of HP infection and the HP virulence factor CagA by a urease test and PCR. the presence of EBV was detected by Eber-1 in situ hybridization.Results: in UE, 85.5% of juvenile patients showed some degree of gastritis (45.3% of patients with mild gastritis and 54.7% with moderate/severe gastritis) and patients with mild gastritis were younger than patients with moderate/severe gastritis. Among adults, 48.7% presented mild gastritis and 51.3% moderate/severe gastritis. HP infection was detected in 0% of normal mucosa, 58.5% of juvenile gastritis patients, 69.2% of adult gastritis patients and 88% of GC patients. in these same groups, HP CagA(+) was detected in 0%, 37.7%, 61.5% and 67.2% of tissue samples, respectively. in juvenile patients, HP infection was more common in those with gastritis than in normal samples (p = 0.004). the patients with either HP or HP CagA(+) were older than patients without these pathogens (p < 0.05). in juvenile patients, HP infection was more frequent in cases of moderate/severe gastritis than in cases of mild gastritis (p = 0.026). Moreover, in patients with GC, HP infection was more frequent in males than in females (p = 0.023). GC patients with HP CagA(+) were older than patients with HP CagA-(p = 0.027). HP CagA(+) was more common in intestinal-type than diffuse-type GC (p = 0.012). HP CagA(+) was also associated with lymph-node (p = 0.024) and distal (p = 0.005) metastasis. No association between EBV infection and HP infection or any clinicopathological variable was detected.Conclusions: Our results suggest that HP is involved in the pathophysiology of severe gastric lesions and in the development of GC, particularly when CagA(+) is present. EBV was not the primary pathogenic factor in our samples.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fed Univ Para, Inst Ciencias Biol, Lab Citogenet Humana, BR-66075110 Belem, PA, BrazilFed Univ Para, Inst Ciencias Saude, BR-66075110 Belem, PA, BrazilCtr Univ Para, Belem, PA, BrazilUniversidade Federal de São Paulo, Dept Ortopedia & Traumatol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Morfol & Genet, Disciplina Genet, São Paulo, BrazilFed Univ Para, BR-66075110 Belem, PA, BrazilUniv Fed Ceara, Fac Odontol, Dept Oral Pathol, Fortaleza, CE, BrazilUniversidade Federal de São Paulo, Dept Ortopedia & Traumatol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Morfol & Genet, Disciplina Genet, São Paulo, BrazilWeb of Scienc

Nitrite Levels Before and after Washing in Salted Fish

Background: Gastric adenocarcinoma is the fourth most common malignancy worldwide and is globally the second leading cause of cancer-related deaths each year. Salted foods and exposure to H. pylori infection during the infancy have been considered the most important environment risk factors for gastric cancer. Despites increased access to electric energy, allowing the use of refrigerators to better conserve foods, many people keep consuming salted food, by washing them before eating with the intention of reducing salted flavor and also supposing to decrease or avoid risk of diseases. The aim of this study was to investigate the efficacy of reducing nitrites levels in salted fish by washing the fish before consuming, to find if washing salted food should be an efficient measure to reduce, or even avoid, the nitrites related gastric cancer risk. Methods: Nine paired samples of fresh and salted fish and 20 additional samples of salted fish were taken for analyses. The nine paired samples were used to comparison of nitrites levels between salted and fresh fish, and the 20 additional salted fish samples for analyses of the effect of washing the fish in reducing nitrites levels. To simulate the usual procedure of living salted fish submersed in fresh water before consumption, we kept the salted samples under water during different periods of time and checked the nitrites levels at each “washing time”. For every experiment a p value of 0•05 was considered, and t-student tests were performed. Results: The washing procedure did not reduce significantly the nitrites levels in salted fish, even after long periods of immersion (p=0•807), and the levels of nitrites in washed salted fish remained much higher than that of the fresh samples, maintaining the consumers exposed to nitrites, known carcinogens related to gastric cancer, and giving an equivocal and hazard feeling of protection to the population. Conclusion: Salted fish has higher concentration of nitrites compared to fresh. Washing, or living salted fish under water, does not provide significant decrease of the nitrites levels.</p

Genomic alterations in diffuse-type gastric cancer as shown by high-resolution comparative genomic hybridization

Gastric adenocarcinoma is a serious public health concern, especially in northern Brazil. Gastric cancer call be subdivided into diffuse and intestinal types. Genetic imbalances in diffuse-type gastric cancer remain largely unknown. in the present study, we analyzed 24 advanced diffuse-type gastric cancer samples from northern Brazil subjects using high-resolution comparative genomic hybridization. We found chromosomal alterations in 75% of samples. in cancers with aneusomies, the mean genomic copy number alteration was 6.4. Losses of chromosome regions exceeded gains. the most frequent losses were located at chromosome regions 11q and 18q (five samples for each region), 1pq, 3q, 4q, 5q, 13q, and 14q (four samples), followed by 2pq, 7p, 9pq, 11p, and 16p (three Samples). Our results confirm that gastric cancer has a complex pattern of chromosomal alterations that call he clue to general chromosomal instability related to the advanced stage of gastric carcinogenesis. Loss of 11q and 18q were the most frequent chromosomal changes in diffuse-type gastric adenocarcinoma in individuals from northern Brazil. Frequent loss of 11q chromosome region in this gastric cancer may be peculiar among this population. (C) 2009 Elsevier Inc. All rights reserved.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Universidade Federal de São Paulo, Dept Morphol & Genet, Div Genet, BR-04023900 São Paulo, BrazilInst Biol Sci, Human Cytogenet Lab, BR-66075900 Belem, Para, BrazilJoao de Barros Barreto Univ Hosp, BR-66073000 Belem, Para, BrazilUniversidade Federal de São Paulo, Dept Morphol & Genet, Div Genet, BR-04023900 São Paulo, BrazilWeb of Scienc

hTERT and TP53 deregulation in intestinal-type gastric carcinogenesis in non-human primates

Despite the high incidence, the molecular events involved in intestinal-type gastric carcinogenesis remains unclear. We previously established an intestinal-type gastric carcinogenesis model in Cebus apella, a New World monkey. in the present study, we evaluated hTERT and TP53 mRNA expression, as well as their protein immunoreactivity, in normal mucosa, non-atrophic gastritis, atrophic gastritis, intestinal metaplasia, and intestinal-type gastric cancer samples of non-human primates treated with N-methyl-nitrosourea. in addition, we evaluated the number of TP53 copies in these samples. Although hTERT immunoreactivity was only detected in gastric cancer, a continuous increase of hTERT mRNA expression was observed from non-atrophic gastritis to gastric tumors. No sample presented p53 immunoreactivity. However, we also observed a continuous decrease of TP53 mRNA expression during the sequential steps of gastric carcinogenesis. Moreover, loss of TP53 copies was observed in intestinal metaplasia and gastric cancer samples. Our study highlights that hTERT and TP53 have a key role in intestinal-type gastric cancer initiation.Universidade Federal de São Paulo, Dept Morfol & Genet, Disciplina Genet, BR-04023900 São Paulo, BrazilFed Univ Para, Inst Ciencias Biol, Lab Citogenet Humana, BR-66059 Belem, Para, BrazilMinist Saude, Ctr Nacl Primatas, Ananindeua, PA, BrazilFed Univ Para, Hosp Univ Joao de Barros Barreto, Unidade Alta Complexidade Oncol, BR-66059 Belem, Para, BrazilUniversidade Federal de São Paulo, Dept Morfol & Genet, Disciplina Genet, BR-04023900 São Paulo, BrazilWeb of Scienc