RESUMO
En Chile, el cáncer es la segunda causa de muerte después de las enfermedades cardiovasculares. Los principales cánceres asociados a muerte en mujeres fueron mama, estómago, vesícula biliar, broncopulmonar y cérvico uterino. Alteraciones de las E-cadherinas han sido relacionadas con varios tipos de cáncer, ya que uno de los principales eventos involucrados con su disfunción es el gatillar la invasión y metástasis del tumor. La inactivación del gen CDH1 ha sido demostrada en el cáncer gástrico difuso y el cáncer de mama lobulillar. Asimismo, la inactivación del gen FHIT parece estar asociado con la progresión a neoplasias más agresivas. Se realizaron determinaciones inmunohistoquímicas (IHQ) en fibroadenomas mamarios y cánceres previamente diagnosticados por RE, RPg y Her2, mostrando positividad en todos los casos. La detección (IHQ) de la expresión de FHIT y E-cadherina en tejidos con patologías benignas y malignizados, puede aportar una importante información diagnóstica y pronóstica en el cáncer de mama.
In Chile, cancer is the second leading cause of death after cardiovascular diseases. The major death-related cancers in women were breast, stomach, gallbladder, lung and cervical cancer. Alterations of E-cadherin have been linked to various cancers, as one of the main events involved in its dysfunction is the trigger of tumor invasion and metastasis. CDH1 gene inactivation has been demonstrated in diffuse gastric cancer and lobular breast cancer. Furthermore, inactivation of the FHIT gene to be associated with progression to more aggressive tumors. Immunohistochemistry (IHC) determinations were performed in fibroadenomas and breast cancers previously diagnosed by ER, PgR and Her2, showing positivity in all cases. Immunohistochemical detection of FHIT and E-cadherin expression in tissues with benign disease and malignant, may provide an important diagnostic and prognostic information in breast cancer.
Assuntos
Humanos , Feminino , Hidrolases Anidrido Ácido/metabolismo , Caderinas/metabolismo , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/metabolismo , Proteínas de Neoplasias/metabolismo , Carcinoma Ductal de Mama/diagnóstico , Carcinoma Ductal de Mama/metabolismo , Carcinoma Lobular/diagnóstico , Carcinoma Lobular/metabolismo , Fibroadenoma/diagnóstico , Fibroadenoma/metabolismo , Imuno-HistoquímicaRESUMO
Background: The loss of tumor suppresor gene function damages the defensive mechanisms that protect the indemnity of genetic material. Promoter gene methylation is one of the inactivation mechanisms of suppressor genes. Aim: To study the methylation pattern of a group of genes in biopsy samples of gastrointestinal tumors. Material and methods: Forty eight gastric, 25 gallbladder, 24 colon and 6 pancreas cancer biopsy samples were randomly selected. The methylation pattern of CDH1, FHIT, CDKN2A, APC and MLH1 genes, was studied using a specific polymerase chain reaction test for methylation. Demographic, morphological and follow up variables of patients bearing the tumors were also analyzed. Results: The general methylation frequency of CDH1, FHIT, CDKN2A, APC and MLH1 genes was 64.1, 56, 39.8, 18.1 and 34 percent respectively. In gastric cancer samples there was a correlation between APC gene methylation and well differentiated tumors; between CDH1 methylation and Lauren diffuse type and the presence of three or more metastasic lymph nodes; between FHIT, CDKN2A and CDH1 gene methylation and male gender. In ¡ess differentiated gallbladder tumors, the frequency of CDH1 methylation was higher. There was a tendency towards a lower survival in colon and gastric cancer when MLH1 (p =0.07) y CDKN2A (p= 0.06) were methylated, respectively. Conclusions: An abnormal methylation pattern was associated with morphological features in gastric and gallbladder cancer and with a tendency towards a lower survival in colon and gastric cancer.
Assuntos
Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Carcinoma/genética , Metilação de DNA/genética , Neoplasias da Vesícula Biliar/genética , Neoplasias Gastrointestinais/genética , Neoplasias Pancreáticas/genética , Estimativa de Kaplan-Meier , Hidrolases Anidrido Ácido/genética , Hidrolases Anidrido Ácido/metabolismo , Caderinas/genética , Carcinoma/metabolismo , Neoplasias da Vesícula Biliar/metabolismo , Neoplasias Gastrointestinais/metabolismo , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Técnicas de Amplificação de Ácido Nucleico , Neoplasias Pancreáticas/metabolismo , Reação em Cadeia da PolimeraseRESUMO
BACKGROUND: Genomic DNA methylation, mutations and allelic deletions explain the inactivation of genes involved in cell proliferation and cell cycle control mechanisms. AIM: To analyze the methylation pattern of important genes related to different carcinogenic mechanisms in patients with breast cancer and the relationship with its biological behavior. MATERIAL AND METHODS: Seventy fresh-frozen breast cancer samples were selected. The methylation specific PCR (MSP) test was used to analyze promoter methylation status for genes CDKN2A (p16), hMLH1, APC, CDH1 (Cadherin E) and FHIT. RESULTS: We found methylation in at least one of the genes studied in 88% of cases and in 3 or more genes in 40.5% of cases. The frequencies of promoter hypermethylation of CDKN2A, hMLH1, APC, CDH1 and FHT were 41.4%, 11.4%, 52.9%, 70% and 42.9%, respectively. We found a relationship between CDKN2A methylatlon and better survival (p=0.002). CDH1 methylation and poor histological differentiation (p=0.007), hMLH1 methylation and non-Mapuche ethnicity (p=-0.03), APC methylation and larger tumor size (p<0.05), FHIT methylatton and lack of estrogen rectptor IHC expression (p<0.05). CONCLUSIONS: The high frequency of promoter methylation in patients with breast cancer confirms its role in breast carcinogenesis. The finding of alterations in the methylation pattern of genes studied and its association with prognostic factors is a helpful tool in the search of new criteria for clinical and therapeutic decision making.
Assuntos
Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Regiões Promotoras Genéticas , Carcinoma Ductal de Mama/genética , Genes Supressores de Tumor , Metilação de DNA , Neoplasias da Mama/genética , Amplificação de Genes/genética , Caderinas/genética , Carcinoma Ductal de Mama/patologia , Estudos de Casos e Controles , Genes APC , Hidrolases Anidrido Ácido/genética , Neoplasias da Mama/patologia , Proteínas Nucleares/genética , Proteínas de Neoplasias/genética , Proteínas de Transporte , Reação em Cadeia da Polimerase/métodosRESUMO
Adenosine 5',5'''-P1,P4-tetraphosphate (Ap4A) and adenosine 5',5'''-P1,P5-pentaphosphate (Ap5A) are stored in and released from rat brain synaptic terminals. In the present study we investigated the hydrolysis of dinucleotides (Ap4A and Ap5A) in synaptosomes from the cerebral cortex of adult rats. Ap4A and Ap5A, but not Ap3A, were hydrolyzed at pH 7.5 in the presence of 20 mM Tris/HCl, 2.0 mM MgCl2, 10 mM glucose and 225 mM sucrose at 37oC. The disappearance of the substrates measured by FPLC on a mono-Q HR column was both time and protein dependent. Since synaptosome integrity was at least 90 percent at the end of the assay, hydrolysis probably occurred by the action of an ecto-enzyme. Extracellular actions of adenine dinucleotides at central nervous system terminate due to the existence of ecto-nucleotidases which specifically cleave these dinucleotides. These enzymes in association with an ATP diphosphohydrolase and a 5'-nucleotidase are able to promote the complete hydrolysis of dinucleotides to adenosine in the synaptic cleft
