RESUMEN
PURPOSE: Anaplastic lymphoma kinase (ALK) rearrangement confers sensitivity to ALK inhibitors (ALKis) in non-small-cell lung cancer (NSCLC). Although several drugs provided an impressive outcome benefit, the most effective sequential strategy is still unknown. We describe outcomes of real-life patients according to the treatment strategy received. PATIENTS: We retrospectively collected 290 ALK rearranged advanced NSCLC diagnosed between 2011 and 2017 in 23 Italian institutions. RESULTS: After a median follow-up of 26 months, PFS for crizotinib and a new generation ALKis were 9.4 [CI 95% 7.9-11.2] and 11.1 months [CI 95% 9.2-13.8], respectively, while TTF were 10.2 [CI 95% 8.5-12.6] and 11.9 months [CI 95% 9.7-17.4], respectively, being consistent across the different settings. The composed outcomes (the sum of PFS or TTF) in patients treated with crizotinib followed by a new generation ALKis were 27.8 months [CI 95% 24.3-33.7] in PFS and 30.4 months [CI 95% 24.7-34.9] in TTF. The median OS from the diagnosis of advanced disease was 39 months [CI 95% 31.8-54.5]. Patients receiving crizotinib followed by a new generation ALKis showed a higher median OS [57 months (CI 95% 42.0-73.8)] compared to those that did not receive crizotinib [38 months (CI 95% 18.6-NR)] and those who performed only crizotinib as target agent [15 months (CI 95% 11.3-34.0)] (P < 0.0001). CONCLUSION: The sequential administration of crizotinib and a new generation ALKis provided a remarkable clinical benefit in this real-life population, being an interesting option to consider in selected patients.
Asunto(s)
Quinasa de Linfoma Anaplásico/genética , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Neoplasias Pulmonares/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/uso terapéutico , Adulto , Anciano , Anciano de 80 o más Años , Quinasa de Linfoma Anaplásico/antagonistas & inhibidores , Carcinoma de Pulmón de Células no Pequeñas/genética , Carcinoma de Pulmón de Células no Pequeñas/patología , Crizotinib/uso terapéutico , Femenino , Reordenamiento Génico , Humanos , Italia , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patología , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Resultado del Tratamiento , Adulto JovenRESUMEN
The gene XRCC3 (X-ray cross complementing group 3) has the task of repairing damage that occurs when there is recombination between homologous chromosomes. Repair of recombination between homologous chromosomes plays an important role in maintaining genome integrity, although it is known that double-strand breaks are the main inducers of chromosomal aberrations. Changes in the XRCC3 protein lead to an increase in errors in chromosome segregation due to defects in centrosomes, resulting in aneuploidy and other chromosomal aberrations, such as small increases in telomeres. We examined XRCC3 Thr241Met polymorphism using PCR-RFLP in 80 astrocytoma and glioblastoma samples. The individuals of the control group (N = 100) were selected from the general population of the São Paulo State. Odds ratio and 95%CI were calculated using a logistic regression model. Patients who had the allele Met of the XRCC3 Thr241Met polymorphism had a significantly increased risk of tumor development (odds ratio = 3.13; 95% confidence interval = 1.50-6.50). There were no significant differences in overall survival of patients. We suggest that XRCC3 Thr241Met polymorphism is involved in susceptibility for developing astrocytomas and glioblastomas.
Asunto(s)
Astrocitoma/genética , Proteínas de Unión al ADN/genética , Glioblastoma/genética , Adolescente , Adulto , Anciano , Alelos , Centrosoma/patología , Niño , Preescolar , Aberraciones Cromosómicas , Segregación Cromosómica/genética , Reparación del ADN , Femenino , Predisposición Genética a la Enfermedad , Variación Genética , Genotipo , Humanos , Lactante , Masculino , Persona de Mediana Edad , Polimorfismo de Nucleótido Simple , Adulto JovenRESUMEN
XRCC genes (X-ray cross-complementing group) were discovered mainly for their roles in protecting mammalian cells against damage caused by ionizing radiation. Studies determined that these genes are important in the genetic stability of DNA. Although the loss of some of these genes does not necessarily confer high levels of sensitivity to radiation, they have been found to represent important components of various pathways of DNA repair. To ensure the integrity of the genome, a complex system of DNA repair was developed. Base excision repair is the first defense mechanism of cells against DNA damage and a major event in preventing mutagenesis. Repair genes may play an important role in maintaining genomic stability through different pathways that are mediated by base excision. In the present study, we examined XRCC1Arg194Trp and XRCC1Arg399Gln polymorphism using PCR-RFLP in 80 astrocytoma and glioblastoma samples. Patients who had the allele Trp of the XRCC1Arg194Trp polymorphism had an increased risk of tumor development (OR = 8.80; confidence interval at 95% (95%CI) = 4.37-17.70; P < 0.001), as did the allele Gln of XRCC1Arg399Gln (OR = 1.01; 95%CI = 0.53-1.93; P = 0.971). Comparison of overall survival of patients did not show significant differences. We suggest that XRCC1Arg194Trp and XRCC1Arg399Gln polymorphisms are involved in susceptibility for developing astrocytomas and glioblastomas.
Asunto(s)
Neoplasias Encefálicas/genética , Proteínas de Unión al ADN/genética , Glioma/genética , Arginina/química , Cartilla de ADN , Proteínas de Unión al ADN/química , Glicina/química , Humanos , Reacción en Cadena de la Polimerasa , Polimorfismo de Nucleótido Simple , Triptófano/química , Proteína 1 de Reparación por Escisión del Grupo de Complementación Cruzada de las Lesiones por Rayos XRESUMEN
Glutathione S-transferases (GSTs) constitute a superfamily of ubiquitous multifunctional enzymes that are involved in the cellular detoxification of a large number of endogenous and exogenous chemical agents that have electrophilic functional groups. People who have deficiencies in this family of genes are at increased risk of developing some types of tumors. We examined GSTP1 Ile105Val polymorphism using PCR-RFLP in 80 astrocytoma and glioblastoma samples. Patients who had the Val allele of the GSTP1 Ile105Val polymorphism had an increased risk of tumor development (odds ratio = 8.60; 95% confidence interval = 4.74-17.87; P < 0.001). Overall survival of patients did not differ significantly. We suggest that GSTP1 Ile105Val polymorphisms are involved in susceptibility to developing astrocytomas and glioblastomas.
Asunto(s)
Astrocitoma/genética , Neoplasias Encefálicas/genética , Glioblastoma/genética , Glutatión Transferasa/genética , Isoleucina/genética , Polimorfismo de Nucleótido Simple , Valina/genética , Adolescente , Adulto , Anciano , Astrocitoma/enzimología , Secuencia de Bases , Neoplasias Encefálicas/enzimología , Estudios de Casos y Controles , Cartilla de ADN , Femenino , Glioblastoma/enzimología , Glutatión Transferasa/química , Humanos , Masculino , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción , Adulto JovenRESUMEN
Disruption or loss of tumor suppressor gene TP53 is implicated in the development or progression of almost all different types of human malignancies. Other members of the p53 family have been identified. One member, p73, not only shares a high degree of similarity with p53 in its primary sequence, but also has similar functions. Like p53, p73 can bind to DNA and activate transcription. Using PCR-SSCP and gene sequencing, we analyzed the TP53 and TP73 genes in a case of a grade III anaplastic astrocytoma that progressed to glioblastoma. We found a deletion of AAG at position 595-597 of TP53 (exon 6), resulting in the deletion of Glu 199 in the protein and a genomic polymorphism of TP73, identified as an A-to-G change, at position E8/+15 at intron 8 (IVS8-15A>G). The mutation found at exon 6 of the gene TP53 could be associated with the rapid tumoral progression found in this case, since the mutated p53 may inactivate the wild-type p53 and the p73alpha protein, which was conserved here, leading to an increase in cellular instability.
Asunto(s)
Astrocitoma/genética , Neoplasias Encefálicas/genética , Proteínas de Unión al ADN/genética , Proteínas Nucleares/genética , Proteína p53 Supresora de Tumor/genética , Proteínas Supresoras de Tumor/genética , Adulto , Secuencia de Bases , Cartilla de ADN , Humanos , Masculino , Reacción en Cadena de la Polimerasa , Polimorfismo Conformacional Retorcido-Simple , Proteína Tumoral p73RESUMEN
The p53 tumor suppressor gene is the most frequently mutated gene in human cancer; this gene is mutated in up to 50% of human tumors. It has a critical role in the cell cycle, apoptosis and cell senescence, and it participates in many crucial physiological and pathological processes. Polymorphisms of p53 have been suggested to be associated with genetically determined susceptibility in various types of cancer. Another process involved with the development and progression of tumors is DNA hypermethylation. Aberrant methylation of the promoter is an alternative epigenetic change in genetic mechanisms, leading to tumor suppressor gene inactivation. In the present study, we examined the TP53 Arg72Pro and Pro47Ser polymorphisms using PCR-RFLP and the pattern of methylation of the p53 gene by methylation-specific PCR in 90 extra-axial brain tumor samples. Patients who had the allele Pro of the TP53 Arg72Pro polymorphism had an increased risk of tumor development (odds ratio, OR = 3.23; confidence interval at 95%, 95%CI = 1.71-6.08; P = 0.003), as did the allele Ser of TP53 Pro47Ser polymorphism (OR = 1.28; 95%CI = 0.03-2.10; P = 0.01). Comparison of overall survival of patients did not show significant differences. In the analysis of DNA methylation, we observed that 37.5% of meningiomas, 30% of schwannomas and 52.6% of metastases were hypermethylated, suggesting that methylation is important for tumor progression. We suggest that TP53 Pro47Ser and Arg72Pro polymorphisms and DNA hypermethylation are involved in susceptibility for developing extra-axial brain tumors.
Asunto(s)
Neoplasias Encefálicas/genética , Metilación de ADN/genética , Genes p53/genética , Meningioma/genética , Estudios de Casos y Controles , Codón , Predisposición Genética a la Enfermedad , Humanos , Neurilemoma/genética , Reacción en Cadena de la Polimerasa , Polimorfismo GenéticoRESUMEN
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.(AU)
Asunto(s)
Humanos , Masculino , Adulto , Femenino , Persona de Mediana Edad , Anciano , Metilación de ADN , Neoplasias Gástricas/genética , Reparación de la Incompatibilidad de ADN , Análisis de Secuencia de ADN , Brasil , Enzimas Reparadoras del ADN/genética , Regiones Promotoras GenéticasRESUMEN
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.
Asunto(s)
Humanos , Masculino , Adulto , Femenino , Persona de Mediana Edad , Metilación de ADN , Neoplasias Gástricas/genética , Reparación de la Incompatibilidad de ADN , Análisis de Secuencia de ADN , Brasil , Enzimas Reparadoras del ADN/genética , Regiones Promotoras GenéticasRESUMEN
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 degrees 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.
Asunto(s)
Adenocarcinoma/genética , Metilación de ADN/genética , Genes p16 , Genes p53 , Neoplasias Gástricas/genética , Complejos de Ubiquitina-Proteína Ligasa/metabolismo , Adenocarcinoma/metabolismo , Adenocarcinoma/patología , Adulto , Anciano , Ciclosoma-Complejo Promotor de la Anafase , Subunidad Apc1 del Ciclosoma-Complejo Promotor de la Anafase , Estudios de Casos y Controles , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa , Regiones Promotoras Genéticas/genética , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patologíaRESUMEN
Cancer is one of the most common and severe problems in clinical medicine, and nervous system tumors represent about 2% of the types of cancer. The central role of the nervous system in the maintenance of vital activities and the functional consequences of the loss of neurons can explain how severe brain cancers are. The cell cycle is a highly complex process, with a wide number of regulatory proteins involved, and such proteins can suffer alterations that transform normal cells into malignant ones. The INK4 family members (CDK inhibitors) are the cell cycle regulators that block the progression of the cycle through the R point, causing an arrest in G1 stage. The p14ARF (alternative reading frame) gene is a tumor suppressor that inhibits p53 degradation during the progression of the cell cycle. The PTEN gene is related to the induction of growth suppression through cell cycle arrest, to apoptosis and to the inhibition of cell adhesion and migration. The purpose of the present study was to assess the mutational state of the genes p14ARF, p15INK4b, p16INK4a, and PTEN in 64 human nervous system tumor samples. Homozygous deletions were found in exon 2 of the p15INK4b gene and exon 3 of the p16INK4a gene in two schwannomas. Three samples showed a guanine deletion (63 codon) which led to a loss of heterozygosity in the p15 gene, and no alterations could be seen in the PTEN gene. Although the group of patients was heterogeneous, our results are in accordance with other different studies that indicate that homozygous deletion and loss of heterozygosity in the INK4 family members are frequently observed in nervous system tumors.
Asunto(s)
Inhibidor p15 de las Quinasas Dependientes de la Ciclina/genética , Inhibidor p16 de la Quinasa Dependiente de Ciclina/genética , Neoplasias del Sistema Nervioso/genética , Fosfohidrolasa PTEN/genética , Proteína p14ARF Supresora de Tumor/genética , Análisis Mutacional de ADN/métodos , Eliminación de Gen , Homocigoto , Humanos , Pérdida de Heterocigocidad , Neoplasias del Sistema Nervioso/patología , Reacción en Cadena de la PolimerasaRESUMEN
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 percent of gastric cancer samples, with 35 percent methylation in diffuse-type and 26.9 percent in intestinal-type cancers. CDKN2A methylation was associated with the carcinogenesis process for ~30 percent 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.
Asunto(s)
Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adenocarcinoma/genética , Metilación de ADN/genética , Neoplasias Gástricas/genética , Complejos de Ubiquitina-Proteína Ligasa/metabolismo , Adenocarcinoma/metabolismo , Adenocarcinoma/patología , Estudios de Casos y Controles , Reacción en Cadena de la Polimerasa , Regiones Promotoras Genéticas/genética , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patologíaRESUMEN
The TP53 tumor suppressor gene codifies a protein responsible for preventing cells with genetic damage from growing and dividing by blocking cell growth or apoptosis pathways. A common single nucleotide polymorphism (SNP) in TP53 codon 72 (Arg72Pro) induces a 15-fold decrease of apoptosis-inducing ability and has been associated with susceptibility to human cancers. Recently, another TP53 SNP at codon 47 (Pro47Ser) was reported to have a low apoptosis-inducing ability; however, there are no association studies between this SNP and cancer. Aiming to study the role of TP53 Pro47Ser and Arg72Pro on glioma susceptibility and oncologic prognosis of patients, we investigated the genotype distribution of these SNPs in 94 gliomas (81 astrocytomas, 8 ependymomas and 5 oligodendrogliomas) and in 100 healthy subjects by the polymerase chain reaction-restriction fragment length polymorphism approach. Chi-square and Fisher exact test comparisons for genotype distributions and allele frequencies did not reveal any significant difference between patients and control groups. Overall and disease-free survivals were calculated by the Kaplan-Meier method, and the log-rank test was used for comparisons, but no significant statistical difference was observed between the two groups. Our data suggest that TP53 Pro47Ser and Arg72Pro SNPs are not involved either in susceptibility to developing gliomas or in patient survival, at least in the Brazilian population.
Asunto(s)
Glioma/genética , Polimorfismo de Nucleótido Simple , Proteína p53 Supresora de Tumor/genética , Adolescente , Adulto , Anciano , Apoptosis/genética , Brasil , Estudios de Casos y Controles , Niño , Preescolar , Femenino , Frecuencia de los Genes , Genes p53 , Predisposición Genética a la Enfermedad , Genotipo , Glioma/etiología , Glioma/mortalidad , Humanos , Lactante , Masculino , Persona de Mediana Edad , Pronóstico , Análisis de SupervivenciaRESUMEN
The TP53 tumor suppressor gene codifies a protein responsible for preventing cells with genetic damage from growing and dividing by blocking cell growth or apoptosis pathways. A common single nucleotide polymorphism (SNP) in TP53 codon 72 (Arg72Pro) induces a 15-fold decrease of apoptosis-inducing ability and has been associated with susceptibility to human cancers. Recently, another TP53 SNP at codon 47 (Pro47Ser) was reported to have a low apoptosis-inducing ability; however, there are no association studies between this SNP and cancer. Aiming to study the role of TP53 Pro47Ser and Arg72Pro on glioma susceptibility and oncologic prognosis of patients, we investigated the genotype distribution of these SNPs in 94 gliomas (81 astrocytomas, 8 ependymomas and 5 oligodendrogliomas) and in 100 healthy subjects by the polymerase chain reaction-restriction fragment length polymorphism approach. Chi-square and Fisher exact test comparisons for genotype distributions and allele frequencies did not reveal any significant difference between patients and control groups. Overall and disease-free survivals were calculated by the Kaplan-Meier method, and the log-rank test was used for comparisons, but no significant statistical difference was observed between the two groups. Our data suggest that TP53 Pro47Ser and Arg72Pro SNPs are not involved either in susceptibility to developing gliomas or in patient survival, at least in the Brazilian population.
Asunto(s)
Humanos , Masculino , Femenino , Preescolar , Niño , Adolescente , Adulto , Persona de Mediana Edad , Glioma/genética , Polimorfismo de Nucleótido Simple , /genética , Apoptosis/genética , Brasil , Estudios de Casos y Controles , Frecuencia de los Genes , Predisposición Genética a la Enfermedad , Genotipo , Glioma/etiología , Glioma/mortalidad , Pronóstico , Análisis de SupervivenciaRESUMEN
The cancer is one of the most common and severe problems in clinical medicine, and nervous system tumors represent about 2% of the types of cancer. The central role of the nervous system in the maintenance of vital activities and the functional consequences of the loss of neurons can explain how severe brain cancers are. The cell cycle is a highly complex process, with a wide number of regulatory proteins involved, and such proteins can suffer alterations that transform normal cells into malignant ones. The INK4 family members (CDK inhibitors) are the cell cycle regulators that block the progression of the cycle through the R point, causing an arrest in G1 stage. The p14ARF (alternative reading frame) gene is a tumor suppressor that inhibits p53 degradation during the progression of the cell cycle. The PTEN gene is related to the induction of growth suppression through cell cycle arrest, to apoptosis and to the inhibition of cell adhesion and migration. The purpose of the present study was to assess the mutational state of the genes p14ARF, p15INK4b, p16INK4a, and PTEN in 64 human nervous system tumor samples. Homozygous deletions were found in exon 2 of the p15INK4b gene and exon 3 of the p16INK4a gene in two schwannomas. Three samples showed a guanine deletion (63 codon) which led to a loss of heterozygosity in the p15 gene, and no alterations could be seen in the PTEN gene. Although the group of patients was heterogeneous, our results are in accordance with other different studies that indicate that homozygous deletion and loss of heterozygosity in the INK4 family members are frequently observed in nervous system tumors.
Asunto(s)
Humanos , /genética , /genética , Neoplasias del Sistema Nervioso/genética , /genética , Análisis Mutacional de ADN/métodos , Eliminación de Gen , Homocigoto , Pérdida de Heterocigocidad , Neoplasias del Sistema Nervioso/patología , Reacción en Cadena de la Polimerasa , Fosfohidrolasa PTENRESUMEN
Gliomas are the most common tumors of the central nervous system. In spite of the marked advances in the characterization of the molecular pathogenesis of gliomas, these tumors remain incurable and, in most of the cases, resistant to treatments, due to their molecular heterogeneity. Gene PAX6, which encodes a transcription factor that plays an important role in the development of the central nervous system, was recently recognized as a tumor suppressor in gliomas. The objective of the present study was to analyze the mutational status of the coding and regulating regions of PAX6 in 94 gliomas: 81 astrocytomas (11 grade I, 23 grade II, 8 grade III, and 39 grade IV glioblastomas), 5 oligodendrogliomas (3 grade II, and 2 grade III), and 8 ependymomas (5 grade II, and 3 grade III). Two regulating regions (SX250 and EIE) and the 11 coding regions (exons 4-13, plus exon 5a resulting from alternative splicing) of gene PAX6 were analyzed and no mutation was found. Therefore, we conclude that the tumor suppressor role of PAX6, reported in previous studies on gliomas, is not due to mutation in its coding and regulating regions, suggesting the involvement of epigenetic mechanisms in the silencing of PAX6 in these tumors.
Asunto(s)
Neoplasias del Sistema Nervioso Central/genética , Proteínas del Ojo/genética , Glioma/genética , Proteínas de Homeodominio/genética , Mutación , Factores de Transcripción Paired Box/genética , Proteínas Represoras/genética , Adolescente , Adulto , Anciano , Astrocitoma/genética , Secuencia de Bases , Niño , Preescolar , Análisis Mutacional de ADN , Cartilla de ADN/genética , ADN de Neoplasias/genética , Ependimoma/genética , Epigénesis Genética , Femenino , Silenciador del Gen , Humanos , Lactante , Masculino , Persona de Mediana Edad , Oligodendroglioma/genética , Factor de Transcripción PAX6 , Reacción en Cadena de la PolimerasaRESUMEN
Gliomas are the most common tumors of the central nervous system. In spite of the marked advances in the characterization of the molecular pathogenesis of gliomas, these tumors remain incurable and, in most of the cases, resistant to treatments, due to their molecular heterogeneity. Gene PAX6, which encodes a transcription factor that plays an important role in the development of the central nervous system, was recently recognized as a tumor suppressor in gliomas. The objective of the present study was to analyze the mutational status of the coding and regulating regions of PAX6 in 94 gliomas: 81 astrocytomas (11 grade I, 23 grade II, 8 grade III, and 39 grade IV glioblastomas), 5 oligodendrogliomas (3 grade II, and 2 grade III), and 8 ependymomas (5 grade II, and 3 grade III). Two regulating regions (SX250 and EIE) and the 11 coding regions (exons 4-13, plus exon 5a resulting from alternative splicing) of gene PAX6 were analyzed and no mutation was found. Therefore, we conclude that the tumor suppressor role of PAX6, reported in previous studies on gliomas, is not due to mutation in its coding and regulating regions, suggesting the involvement of epigenetic mechanisms in the silencing of PAX6 in these tumors.
Asunto(s)
Humanos , Masculino , Femenino , Preescolar , Niño , Adolescente , Adulto , Persona de Mediana Edad , ADN de Neoplasias/genética , Glioma/genética , Mutación , Neoplasias del Sistema Nervioso Central/genética , Proteínas Represoras/genética , Proteínas de Homeodominio/genética , Proteínas del Ojo/genética , Astrocitoma , Secuencia de Bases , Análisis Mutacional de ADN , Epigénesis Genética , Ependimoma/genética , Factores de Transcripción Paired Box/genética , Silenciador del Gen , Oligodendroglioma/genética , Reacción en Cadena de la Polimerasa , Cartilla de ADN/genéticaRESUMEN
Fibroadenoma (FA) is a benign breast tumour that occurs in about 25% of women. Cytogenetic studies suggest that numerical chromosomal aberrations may contribute to tumorigenesis, but chromosomal instability is still poorly characterised in breast cancer. The aim of this study was to investigate numerical alterations of chromosome 21 in 15 breast FAs. All samples were analysed by classical cytogenetics and by fluorescence in situ hybridisation (FISH) for chromosome 21 DNA sequences. Classical cytogenetics analysis showed that all cells were diploidies with modal number varying between 43 and 47 chromosomes, and clonal chromosome alterations in 46.7% of tumours. Clonal numerical alterations involved, preferentially, chromosomes 8, 10, 12, 16 and 21. FISH analysis showed a statistically significant difference for chromosome 21 monosomy between seven samples and control group. This monosomy varied from 24.5% to 43.5% of analysed cells. The presence of chromosomal alterations in FAs may be a consequence of the proliferation process and is probably not related to the aetiology of this type of lesion. The study of benign proliferations and comparison with chromosome alterations in their malignant counterparts should result in an understanding of the genes acting in cell proliferation alone and those that cause these cells to both undergo malignant transformation and become invasive.
Asunto(s)
Aneuploidia , Neoplasias de la Mama/genética , Cromosomas Humanos Par 21/genética , Fibroadenoma/genética , Hibridación Fluorescente in Situ , Adolescente , Adulto , Análisis Citogenético , Femenino , Humanos , Monosomía , Estadística como AsuntoRESUMEN
Gastric cancer is the second most frequent type of neoplasia and also the second most common cause of death in the world. TP53 codon 72, which produces variant proteins with an arginine (Arg) or proline (Pro), has been reported to be associated with cancers of the lung, oesophagus, stomach and cervix. Werner's syndrome (WS) is a premature ageing disease caused by a mutation in the WRN gene. The WRN protein acts as a DNA helicase and as an exonuclease. WRN codon 1367 produces variant proteins with an Arg or cysteine (Cys). This polymorphism has been studied, in order to understand the clinical impact of the molecular variants in WS and in age-related disorders. In the present study, the TP53 codon 72 and the WRN codon 1367 polymorphisms were investigated in 54 gastric adenocarcinoma patients (31 diffuse-type and 25 intestinal-type) and 54 controls. DNA samples were extracted, and PCR-RFLP was utilised for genotyping TP53 codon 72 and WRN codon 1367. The allele frequencies of the TP53 polymorphism were: Arg=0.74 and Pro=0.26. The allele frequencies of the WRN polymorphism were: Cys=0.73 and Arg=0.27. The crude genotypic frequencies in gastric cancer patients were similar to those of the controls, but in the WRN codon 1367 polymorphisms the mean age tended to be higher in the Arg/Arg genotypes. There also was an association, although not statistically significant, between the presence of Helicobacter pylori and the genotypes Cys/Cys and Cys/Arg and a higher percentage of cardia cancer among the Arg/Arg genotypes, and of non-cardia cancer among genotypes Cys/Cys and Cys/Arg. These findings may be a reflection of differences in the interaction between WRN codon 1367 polymorphisms and local factors in the stomach. To our knowledge, this is the first study to examine a genetic polymorphism of the WRN gene in cancer. The precise mechanisms of action of the TP53 and WRN polymorphisms involved in the aetiopathogeny of this disease need further investigation.
Asunto(s)
Adenocarcinoma/genética , Codón , ADN Helicasas/genética , Genes p53 , Polimorfismo Genético , Neoplasias Gástricas/genética , Secuencia de Bases , Brasil , Cartilla de ADN , Exodesoxirribonucleasas , Humanos , Reacción en Cadena de la Polimerasa , RecQ Helicasas , Helicasa del Síndrome de WernerRESUMEN
Among all tumours diagnosed worldwide, gastric adenocarcinoma is the second most frequent type of malignancy. In Brazil, it is estimated to be the fifth most frequent type of neoplasia. According to the classification of Laurén, these tumours are divided into well differentiated and ill differentiated gastric adenocarcinomas. There are studies suggesting that the first type develops through remodulation of genes involved in the suppressor pathway and the second through remodulation of genes belonging to the mutational pathway. The gene PTEN is located in region 10q23 and is altered in several human tumours. In gastric cancer, this gene is thought to take part in the suppressor pathway. In our study, DNA was obtained from 48 gastric adenocarcinoma samples, amplified, screened for all exons of the PTEN gene by PCR-SSCP and then confirmed by sequencing. There was only one sample that presented an alteration and that was a transversion. Our results corroborate the hypothesis that somatic alterations in the PTEN gene are rare events in gastric cancer.
Asunto(s)
Adenocarcinoma/genética , Genes Supresores de Tumor , Fosfohidrolasa PTEN/genética , Neoplasias Gástricas/genética , Secuencia de Bases , Cartilla de ADN , Humanos , Mutación Puntual , Reacción en Cadena de la Polimerasa , Polimorfismo Conformacional Retorcido-SimpleRESUMEN
Gastric cancer is the second most frequent type of neoplasia and also the second most important cause of death in the world. Virtually all the established cell lines of gastric neoplasia were developed in Asian countries, and western countries have contributed very little to this area. In the present study we describe the establishment of the cell line ACP01 and characterize it cytogenetically by means of in vitro immortalization. Cells were transformed from an intestinal-type gastric adenocarcinoma (T4N2M0) originating from a 48-year-old male patient. This is the first gastric adenocarcinoma cell line established in Brazil. The most powerful application of the cell line ACP01 is in the assessment of cytotoxicity. Solid tumor cell lines from different origins have been treated with several conventional and investigational anticancer drugs. The ACP01 cell line is triploid, grows as a single, non-organized layer, similar to fibroblasts, with focus formation, heterogeneous division, and a cell cycle of approximately 40 h. Chromosome 8 trisomy, present in 60 percent of the cells, was the most frequent cytogenetic alteration. These data lead us to propose a multifactorial triggering of gastric cancer which evolves over multiple stages involving progressive genetic changes and clonal expansion.