Oxidative stress and plasma lipoproteins in cancer patients / Estresse oxidativo e lipoproteínas plasmáticas em pacientes com câncer

Objective To evaluate the relation between oxidative stress and lipid profile in patients with different types of cancer. Methods This was an observational cross-sectional. A total of 58 subjects were evaluated, 33 males, divided into two groups of 29 patients each: Group 1, patients with cancer of the digestive tract and accessory organs; Group 2 patients with other types of cancers, all admitted to a public hospital. The plasma levels (lipoproteins and total cholesterol, HDL, and triglycerides, for example) were analyzed by enzymatic kits, and oxidative stress based on thiobarbituric acid-reactive substances, by assessing the formation of malondialdehyde. Results In general the levels of malondialdehyde of patients were high (5.00μM) as compared to 3.31μM for healthy individuals. The median values of lipids exhibited normal triacylglycerol (138.78±89.88mg/dL), desirable total cholesterol values (163.04±172.38mg/dL), borderline high LDL (151.30±178.25mg/dL) and low HDL (31.70±22.74mg/dL). Median HDL levels in Group 1 were lower (31.32mg/dL) than the cancer patients in Group 2 (43.67mg/dL) (p=0.038). Group 1 also showed higher levels of oxidative stress (p=0.027). Conclusion The lipid profile of patients with cancer was not favorable, which seems to have contributed to higher lipid peroxidation rate, generating a significant oxidative stress. .

Objetivo Avaliar a relação entre estresse oxidativo e perfil lipídico em pacientes com diferentes tipos de câncer. Métodos Estudo do tipo observacional transversal. Foram avaliados 58 indivíduos, sendo 33 do sexo masculino, divididos em dois grupos de 29 pacientes cada: o Grupo 1 foi formado por pacientes com câncer do trato digestivo e órgãos anexos; o Grupo 2 foi formado por pacientes com outros tipos de câncer, todos internados em um hospital público. Foram analisadas concentrações plasmáticas (colesterol total, HDL e triacilglicerol, entre outras), por meio de kits enzimáticos, e o estresse oxidativo, com base em substâncias reativas ao ácido tiobarbitúrico, por meio da formação de malondialdeído. Resultados Na mediana, os pacientes apresentaram valores altos de malondialdeído (5,00μM) quando comparados ao valor de 3,31μM para indivíduos saudáveis. A mediana do perfil lipídico exibiu valores de triacilgliceróis normais (138,78±89,88mg/dL), colesterol total com valores desejáveis (163,04±172,38mg/dL), LDL com limiar elevado (151,30±178,25mg/dL) e HDL baixo (31,70±22,74mg/dL). Os níveis medianos de HDL do Grupo 1 foram mais baixos (31,32mg/dL) do que dos pacientes oncológicos do Grupo 2 (43,67mg/dL) (p=0,038). O Grupo 1 apresentou níveis mais altos de estresse oxidativo (p=0,027). Conclusão O perfil lipídico de pacientes com câncer apresentou-se desfavorável, o que parece ter contribuído para uma maior taxa de peroxidação lipídica, gerando um significativo estresse oxidativo. .

Expression and Clinicopathological Significance of CD9 in Gastrointestinal Stromal Tumor

This study investigated the expression and clinicopathological significance of CD9 in gastrointestinal stromal tumor (GIST). Immunohistochemistry staining for CD9 was performed on tumor tissues from 74 GIST patients. The correlation with clinicopathological features, risk classification and prognosis was analyzed. CD9-positive staining comprised 59.5% (44/74) of the GIST patients. The CD9-positive expression rate of the sample was significantly associated with diameter (P = 0.028), mitotic counts (P = 0.035), risk classification (P = 0.018) and three-year recurrence-free survival (RFS) (P < 0.001). Cox proportional hazards regression (HR = 0.352; P = 0.015) showed that CD9 is an independent factor for post-operative RFS. The subgroup analysis showed that CD9 expression in gastric stromal tumor (GST) is significantly associated with diameter (P = 0.031), risk classification (P = 0.023) and three-year RFS (P = 0.001). The Cox proportional hazards regression (HR = 0.104; P = 0.006) also showed that CD9 is an independent factor for RFS of GST. However, CD9 expression does not have a statistically significant correlation with clinicopathological features, risk classification, and prognosis in non-GST. In conclusion, CD9 expression in GIST appears to be associated with the recurrence and/or metastasis of GIST patients, especially in GST, which may indicate the important role of CD9 in the malignant biological behavior and prognosis of GST.

Características genético-moleculares de los tumores estromales gastrointestinales (GIST) / Molecular and genetic features of gastrointestinal stromal tumors (GIST)

Los tumores estromales gastrointestinales (GIST) son neoplasias mesenquimales que típicamente surgen a nivel del estómago, intestino delgado, colon, y otros sitios en la cavidad abdominal y su identificación se ha incrementado por mejoras en los criterios de detección. La mayor parte de los tumores GIST son causados por mutaciones activadoras en los genes de receptores transmembranares tirosina quinasa c-KIT y receptor alpha del factor de crecimiento derivado de plaquetas (PDGFRA). Las mutaciones causales de GIST se restringen solo a ciertas regiones del gen que corresponden a importantes zonas funcionales de c-KIT o PDGFRA. Se reporta que hasta 70% de casos de GIST se debe a mutaciones en el exón 11 del gen c-Kit que corresponde a la región yuxtamembrana del receptor. La región y el tipo de mutación determinan diferencialmente cómo se desarrolla la neoplasia, el pronóstico y su respuesta a inhibidores de las tirosina quinasas como el Imanatib. Por tal motivo, el genotipado de KIT y PDGFRA es importante para el diagnóstico y establecimiento de la sensibilidad a los inhibidores tirosina quinasa.

Gastrointestinal stromal tumors (GISTs) are mesenchymal neoplasms typically arising in the stomach, small intestine, colon, and other sites in the abdominal cavity and its identification has improved dramatically mainly due to better criteria in its detection. Most GISTs tumors harbor activating mutations in the tyrosine kinase receptor c-KIT or platelet derived growth factor receptor-alpha (PDGFRA). Those mutations are restricted to a few regions corresponding to important functional domains of c-KIT or PDGFRA. Upto 70% of cases are due to mutations in exon 11 of c-KIT corresponding to its juxtamembrane region of the receptor. The location and type of mutation will differentially determine the development of the disease, its prognosis and the response to inhibitors of tyrosine kinases as Imanatib. For this reason, genotyping c-KIT and PDGFRA is important for GIST diagnosis and assessment of sensitivity to tyrosine kinase inhibitors.

Ki-67 expression score correlates to survival rate in gastrointestinal stromal tumors (GIST) / Escore de expressão de Ki-67 correlaciona-se com taxa de sobrevida em tumores estromais gastrointestinais (GIST)

PURPOSE: To evaluate the immunohistochemical expression of p16, Ki-67, p53 and Bcl-2 proteins in gastrointestinal stromal tumors (GIST); to assess the possible association between these variables and clinical and histopathological factors of cancer; and to check for prognostic value of these variables (survival and recurrence). METHODS: A sample of 55 patients treated surgically for GIST in three hospitals was studied. The surgically excised tumors were confirmed as GIST by KIT, vimentin, desmin S100 protein, CD117, 1A4 and CD34 assessment in paraffin blocks. RESULTS: Only 9 (16%) cases of GIST were positive for p53, p16 was positive among 43.6%; 80% of GISTs showed staining for Bcl-2. The proliferative index (expressed as the proportion of positive cells) assessed by immunohistochemical expression of Ki-67 was high in 49% of cases. Elevated Ki-67 scores were associated to high histological grade (p=0.0026) and mitosis index, MI (p=0.0001). High Ki-67 index was associated to death. Expression of p53, p16 and Bcl-2 did not correlate to morphological or clinical variables. CONCLUSIONS: Ki-67 immunohistochemical evaluation should be included in preoperative evaluation of GIST biopsies or surgical specimens as a prognostic tool for clinical staging; and all other proteins studied (Bcl-2, p53 and p16) did not play a role in GIST metabolic or carcinogenic process, remaining without prognostic value.

OBJETIVO: Avaliar a expressão imunoistoquímica de p16, Ki-67, p53 e Bcl-2 proteínas em tumores gastrointestinais estromais (GIST); determinar a possível associação entre essas variáveis e fatores clínicos e histopatológicos de câncer, e para verificar o valor prognóstico destas variáveis (sobrevivência e recorrência). MÉTODOS: Uma amostra de 55 pacientes tratados cirurgicamente para GIST em três hospitais foi estudada. Os tumores extirpados cirurgicamente foram confirmados como GIST por KIT, vimentina, proteína desmina S100, CD117, 1A4 e avaliação de CD34 em blocos de parafina. RESULTADOS: Apenas nove (16%) casos de GIST foram positivos para p53, p16 foi positiva em 43,6%, 80% dos GIST apresentaram coloração para Bcl-2. O índice proliferativo (expresso como a proporção de células positivas), avaliado pela expressão imunoistoquímica de Ki-67, foi elevado em 49% dos casos. Escores de Ki-67 elevados foram associados com alto grau histológico (p=0,0026) e índice de mitose, MI (p=0,0001). Alto índice de Ki-67 foi associado à morte. Expressão da p53, p16 e Bcl-2 não se correlacionou com as variáveis morfológicas ou clínicas. CONCLUSÕES: A avaliação imunoistoquímica de Ki-67 deve ser incluída na avaliação pré-operatória de biópsias ou peças cirúrgicas de GIST como uma ferramenta prognóstica para o estadiamento clínico, e todas as outras proteínas estudadas (Bcl-2, p53 e p16) não desempenharam um papel no processo metabólico ou carcinogênico em GIST, mantendo-se sem valor prognóstico.

Estudio de patrones de metilación génica en tumores del tubo digestivo / Gene methylation patterns in digestive tumors

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.

Downregulation of regenerating islet-derived 3 alpha (REG3A) in primary human gastric adenocarcinomas

Gastric carcinoma is considered to be one of the most prevalent cancers worldwide. We have performed differential-display polymerase chain reaction (DD-PCR) in order to compare the gene expression profile of gastric carcinoma and that of a normal stomach, in an attempt to identifiy differentially expressed genes associated with primary human gastric cancers. One of the down-regulated genes in gastric cancers was identified as regenerating islet-derived 3 alpha (REG3A), also known as hepatocarcinoma-intestine-pancreas/ pancreatitis-associated protein (HIP/PAP). REG3A exhibited relatively high expression levels in normal gastric mucosa. However, REG3A was found to be down-regulated in 67% (20 out of 30 samples) of primary human gastric cancers, as determined by RT-PCR. In addition, REG3A mRNA expression was not detected in stomach cancer cell lines, SNU cells. Immunohistochemical analysis further confirmed the down-regulation of REG3A expression in primary human gastric cancers. Treatment with the demethylating agent, 5-aza-2'-deoxycytidine (5-Aza-dC) resulted in the restoration of REG3A mRNA expression in the gastric cancer cell line, indicating that the transcriptional silencing of REG3A in SNU cell lines was caused by DNA methylation. Taken together, these data indicate that REG3A is down-regulated in most primary human gastric cancer cells, and might be useful in the diagnosis of gastric cancer. Further characterization of the differentially expressed gene, REG3A, should lead to a better understanding of the changes occurring at the molecular level during the development and progression of primary human gastric cancer.

Hepatocyte Expressions in Hepatocellular Carcinomas, Gastrointestinal Neoplasms, and Non-neoplastic Gastrointestinal Mucosa: its Role as a Diagnostic Marker

We performed immunohistochemical staining against Hepatocyte (Hep) and CD10 antibodies in 75 hepatocellular carcinoma (HCC), 50 cholangiocarcinomas, 49 colorectal adenocarcinomas, and 308 gastric adenocarcinomas by tissue array method. We also evaluated the various non-neoplastic adult tissues and fetal digestive organs. Hep was expressed in 80% of HCCs, and HCCs without Hep expression were more likely to have a higher Edmondson & Steiner grade than HCCs with Hep expression (p=0.004). In non-HCCs, 16% of cholangiocarcinomas, 8.2% of colorectal carcinomas, and 44.2% of gastric carcinomas expressed Hep. Gastric carcinomas with Hep expression were significantly associated with early gastric carcinomas (p<0.001). In non-neoplastic tissues, Hep was found expressed in normal hepatocytes, small intestinal mucosa, and intestinal metaplasia of the stomach. Fetal hepatocytes expressed Hep after 19 weeks of gestation. CD10 was detected in 46.7% (35/75) of HCCs, and canalicular staining pattern was predominant in HCCs. In conclusion, the expression of Hep and CD10 may help to distinguish HCCs from non-HCCs.

Immunohistochemical identification of mesenchymal tumors of the gastrointestinal tract

El origen de los tumores mesenquimáticos del tracto gastrointestinal tradicionalmente considerados musculares ha sido recientemente debatido postulándose que algunos de ellos serían en realidad derivados de células del sistema nervioso periférico. En el presente trabajo hemos estudiado una serie de tumores mesenquimáticos digestivos empleando un antisuero para S-100 y dos antisueros para proteínas de filamentos intermedios: la proteína gliofibrilar ácida (PGFA), y la desmina. La técnica utilizada fue la de peroxidasa-antiperoxidasa empleando antisueros policlonales obtenidos de DAKO (Dinamarca). Se estudiaron 24 tumores mesenquimáticos del tracto digestivo (Tabla 1). Las localizaciones fueron: 1 de esófago, 16 de estómago, 6 de intestino delgado y 1 de colon. Los mismos fueron diagnosticados como: leiomioma (18 casos), leiomioblastoma (3 casos) y leiomiosarcomas (3 casos). Como grupo control se estudiaron 5 leiomiomas uterinos. Estos resultaron uniformemente positivos para desmina y negativos para S-100 y PGFA. Diez casos fueron positivos con el antisuero para desmina; correspondiendo éstos a 9 leiomiomas y 1 leiomioblastoma (Tabla 2). Seis (25%) de los tumores expresaron marcadores neurales: 5 fueron positivos con S-100, 4 con PGFA y correspondieron a 3 leiomiomas, 1 leiomioblastoma y 2 leiomiosarcomas. En ningún tumor se observó tinción simultánea para desmina y algunos de los marcadores neurales. Ocho casos (33%) fueron negativos con todos los antisueros empleados siendo: 6 leiomiomas; 1 leiomioblastoma y 1 leiomiosarcomas. Nuestros resultados sugieren la existencia de por lo menos dos grupos de tumores de acuerdo a sus características inmunohistoquímicas: aquellos de origen miogénico y los derivados de células del sistema periférico. Los tumores negativos para ambos grupos de marcadores podrán probablemente ser clasificados mediante otras técnicas inmunohistoquímicas o ultraestructurales...