Gliomas malignos: biología molecular y detalles oncogenéticos / Wicked gliomas: molecular biology and oncogenetics detail

RESUMEN La biología de los gliomas malignos se asocia con el balance de la expresión de las proteínas que controlan de manera positiva o negativa el ciclo celular, la proliferación, la motilidad, la neoformación vascular y el reconocimiento del sistema inmune. La frecuencia de las alteraciones genéticas que están presentes en GBM2 y GBM1 son diferentes así como la edad de los pacientes en la que se presentan. Mientras que los GBM1 suelen aparecer en edades más tardías, alrededor de los 60-70 años, los GBM2 suelen presentarse en edades más tempranas, 40-50 años. En la génesis del glioblastoma existen alteraciones moleculares a nivel de genes supresores de tumores, oncogenes y genes reparadores de ADN (AU).

ABSTRACT The glioblastoma it is the primary wicked tumor of the central nervous system more common in adults and it invariably associates to a bad presage. The biology of the wicked gliomas associates with the balance of the expression of the proteins that they control of positive way or negative the cellular cycle, the proliferation, the motility, the vascular neoformation and the recognition of the immune system. The frequency of the genetic alterations that they are present in GBM2 and GBM1 is different. While the GBM1 usually appears in later ages, around the 60-70 years, the GBM2 usually presents in earlier ages, 40-50 years. In the genesis of the glioblastoma exist molecular alterations at level of suppressive genes of tumors (GST), oncogenes and reparative genes of DNA (AU).

Análisis de metilación en los genes supresores de tumores CDKN2B y DBC1 en pacientes colombianos con diagnóstico de leucemia / Methylation analysis of the CDKN2B and DBC1 tumour suppressor genes in leukaemia patients in Colombia

Objetivo: Analizar la metilación en los promotores de los genes CDKN2B y DBC1 en muestras de pacientes con leucemia linfoblástica aguda (LLA), leucemia mieloblástica aguda (LMA) y leucemia mieloide crónica (LMC). Además, correlacionar el perfil de metilación de los pacientes con los hallazgos citogenéticos. Materiales y métodos: Se evaluaron 56 pacientes con leucemias: 24 con LLA, 16 con LMA y 16 con LMC. El ADN extraído se modificó con bisulfito de sodio. Se realizó un análisis de metilación en los genes CDKN2B y DBC1 mediante la PCR específica de metilación (MS-PCR). Las muestras positivas por la técnica MS-PCR fueron secuenciadas. Resultados: Se encontró una frecuencia total de metilación del 87,5%. El gen CDKN2B se encontró metilado en el 75% de LLA y de LMC, y del 62% en LMA. El gen DBC1 se encontró metilado en el 96% de LLA, el 94% de LMA y del 68,8% en LMC. El gen más frecuentemente metilado en todas las muestras fue DBC1. De los tres tipos de leucemias, la LLA fue la que presentó los mayores porcentajes de metilación. El 62,5% de la muestras tenían metilado ambos genes. Las muestras con cariotipo normal presentaron una alta frecuencia de metilación de CDKN2B y DBC1. Conclusiones: En este estudio se demostró, por primera vez en pacientes colombianos con leucemias, que la metilación de los genes CDKN2B y DBC1 es un evento frecuente. Los hallazgos indican que la metilación de genes supresores de tumores es una vía molecular alterna que podría estar relacionada con el desarrollo de neoplasias hematológicas.

Objective: To perform a methylation analysis in the CDKN2B and DBC1 gene promoters in samples from Colombian patients with acute lymphoblastic leukaemia (ALL), acute myeloid leukaemia (AML), and chronic myeloid leukaemia (CML), and to correlate the methylation profile with cytogenetic findings. Material and methods: The study included a total of 56 bone marrow samples, 24 from patients with ALL, 16 from AML patients, and 16 from CML patients. DNA was extracted from these samples and converted with sodium bisulphite. Methylation analysis was performed using methylation specific PCR (MS-PCR). The samples that were positive for MS-PCR were sequenced to confirm the results. Results: A total methylation frequency of 87.5% was found. CDKN2B gene promoter hypermethylation was found in 75% of ALL and CML samples, and 62% in AML; while DBC1 gene promoter hypermethylation was found in 96% of the samples of ALL, 94% of AML, and in 68.8% of CML. The most frequently methylated gene in all samples was DBC1. ALL was the type of leukaemia that had the highest percentages of methylation. Almost two-thirds (62.5%) of the samples had both methylated genes. Samples with normal karyotype had a high frequency of methylation in CDKN2B and DBC1 genes. Conclusions: This study showed, for the first time in Colombian patients with leukaemia, that methylation of DBC1 and CDKN2B genes is a common event. Our findings indicate that methylation of tumour suppressor genes is an alternate genetic pathway related to the development of haematological malignancies.

Annotation of Genes Having Candidate Somatic Mutations in Acute Myeloid Leukemia with Whole-Exome Sequencing Using Concept Lattice Analysis

In cancer genome studies, the annotation of newly detected oncogene/tumor suppressor gene candidates is a challenging process. We propose using concept lattice analysis for the annotation and interpretation of genes having candidate somatic mutations in whole-exome sequencing in acute myeloid leukemia (AML). We selected 45 highly mutated genes with whole-exome sequencing in 10 normal matched samples of the AML-M2 subtype. To evaluate these genes, we performed concept lattice analysis and annotated these genes with existing knowledge databases.

Cáncer de mama asociado a mutaciones genéticas de los BRCA 1 y 2 / Breast cancer associated to BRCA 1 and 2 genetic mutations

Entre el 5 al 10 % de los cánceres de ovario y mama son atribuidos a una transmisión autosómica dominante de mutaciones heredadas en los genes BRCA 1 y BRCA 2. Estos explican el 90 % y el 50 % de los cánceres hereditarios de ovario y mama, respectivamente. Las mujeres que heredan la mutación en el gen BRCA tienen mayor riesgo de cáncer de mama, de ovario y los varones poseedores de dicho gen tienen un riesgo de cáncer de próstata. Las mujeres con la mutación en el gen BRCA 2 también tienen riesgo (aunque menor) de presentar cáncer de mama y de ovario, y en varones hay un riesgo de cáncer de mama. Sin embargo, hay otros síndromes que explican el cáncer hereditario de mama y ovario y otros genes que aún están por descubrirse. Entre estos están el Lynch II, el síndrome Li-Fraumeni, el síndrome de ataxia – telangiectasia, el síndrome de Cowden y el síndrome de Bloom. En la actualidad es posible ofrecer la identificación de estas mutaciones con base en el DNA y en una historia familiar completa, pero la utilidad de la predicción de las pruebas genéticas requiere de una adecuada asesoría para la interpretación de sus resultados.

Between 5 and 10 % of breast and ovarian cancers can be traced to an autosomal dominant mode of inheritance of hereditary mutations in a pair of genes known as BRCA 1 and BRCA 2. They explain 90 % and 50 % of hereditary breast and ovarian cancer, respectively . Women carrying a mutation in the BRCA 1 gene, have a life risk for developing breast cancer and for ovarian cancer, a higher risk of colon cancer and men have a high risk of prostatic cancer. Women having the BRCA 2 gene mutation also have the same risk to develop breast cancer but the ovarian cancer is lower (10 % at 70 years) and is characterized for a risk of 6 % of breast cancer in men. Besides there are other known causes of these hereditary syndromes, other implicated genes still to be discovered. The more renoume syndromes are Lynch II, Li-Fraumeni, Ataxia – Telangiectasia, Cowden and Bloom syndromes, etc. Currently, it is possible to convey detection of carriers of these mutations based on DNA and a complete family history, but the useful prediction of genetic tests requires a formal counseling to interpret the results.

Bases moleculares del cáncer / The molecular fundamentals of cancer

El cáncer es una enfermedad caracterizada por la proliferación anormal de células neoplásicas, dada en esencia por alteraciones genéticas y epigenéticas. El control de las diferentes funciones celulares está dado por los genes codificados en el ADN, por lo tanto algunas alteraciones en genes que codifican para las proteínas involucradas en el ciclo de proliferación celular pueden inducir una cascada de eventos que llevan a la producción del fenotipo cancerígeno. La transformación maligna requiere que ocurran alteraciones en genes específicos que controlan la proliferación celular, la apoptosis y el mantenimiento de la integridad del ADN en la misma célula. Las mutaciones tienen la posibilidad de aparecer de manera esporádica o de heredarse, pueden ser sustituciones de bases, adiciones, deleciones o cambios epigenéticos. El presente artículo revisa conceptos moleculares involucrados en la génesis del cáncer.

Cancer is a disease featured by the abnormal proliferation of neoplastic cells mainly given by genetic and epigenetic alterations. The various functions of cells are controlled by the genes encoded in the DNA, thus, alterations in the genes encoded for the proteins involved in the cell proliferation cycle may be involved in a cascade of events which lead to the development of a cancer phenotype. Malignant transformation requires alterations to occur in specific genes which control cell proliferation, apoptosis and maintenance of the DNA integrity in the cell itself. Mutations may be inherited or may sporadically occur, they may be base substitutions, additions, deletions or epigenetic changes. This article reviews the molecular concepts involved in cancer progression.

novel MEFV gene mutation [A511V] in a Chilean FMF patient

Familial Mediterranean fever [FMF] is an autosomal recessive disease which is characterized by recurrent fever and inflammation of serous membranes. A Chilean FMF patient was investigated for MEFV mutations. After DNA extraction, exons 3, 5, 10 and 30UTR region of MEFV gene were analyzed by DNA sequencing while E148Q and R202Q mutations of exon 2 were detected by RFLP. A novel missense mutation, A511V [c.1532C>T, p.Ala511Val], was found in a heterozygous state in exon 5 of MEFV gene. Also, R202Q [c.605G>A, p.Arg202Gln] was detected in heterozygous state. R202Q was of clinical value in the diagnosis of FMF when combined with a disease causing mutation. In this patient, A511V was detected in compound heterozygous state with R202Q and this association may play an important role in FMF

Genética e epigenética: bases moleculares da formação inicial do câncer de mama / Genetics and epigenetics: molecuclar basis of initial formation of breast cancer

O câncer de mama tem origem monoclonal em célula-tronco ou progenitora por meio de mecanismos genéticos (dependentes de lesão no DNA) e epigenéticos (independentes de modificações na sequência do DNA). Através do modelo dos dois eventos nos cromossomos homólogos (teoria de Knudson), é apresentado o processo de inativação de genes supressores para iniciação da carcinogênese mamária tanto no câncer de mama esporádico (não-famíliar) como no hereditário (familiar). São discutidas as mutações genéticas e as alterações epigenéticas que levam ao silenciamento de uma mensagem genética, como a metilação do DNA, modificação nas histonas e microRNA.

Breast cancer originates in monoclonal stem cell or progenitor through genetic mechanisms (dependent DNA damage) and epigenetic (independent of changes in DNA sequence). The model of two events in homologous chromosomes (Knudson's theory) is presented the process of inactivation of tumor suppressor genes for initiation of mammary carcinogenesis both in sporadic breast cancer (non-Family) and in hereditary (familial). It discusses the genetic mutations and epigenetic changes that lead to the silencing of a genetic message, such as DNA methylation, and histone modification in microRNA.

Connexin 26 gene mutations in patients with non-syndromic hearing loss

The etiology of hearing loss is heterogeneous. One of the causes is the genetic hearing loss which may be syndromic or non-syndromic. Mutations in the gap junction of beta 2 [GJB2] gene which encode connexin 26 [CX26] protein are a major cause of non-syndromic hearing loss. The aim of this work was to assess mutations of CX26 gene in adults with non-syndromic hearing loss. Twenty seven patients with non-syndromic hearing loss, family history of hearing loss and consanguinity were examined for Cx26 gene mutations by polymerase chain reaction [PCR] and subsequent sequencing. Relatives of these patients were examined by Multi-Frequency Pure Tone Audiometry [MFPTA]. The percentage of positive mutations in patients with hearing loss was 70.4%, Four types of Cx26 gene mutations were found in these patients. They were: 35delG [deletion/frameshift mutation], RI43W mutation [missense mutation with nucleotide change 426C-T at codon 143 R-W], V271 mutation [polymorphic mutation with nucleotide change 79G-A at codon 27V-l] and 235delC [deletion/frameshift mutation]. 35delG mutation was the most frequent type of mutation as it was detected in 78.9% of cases Moreover, 70% of cases with this mutation were homozygous. On the other hand, notches of MFPTA were found in 52.63% of the relatives. We can conclude that Knowledge of the genetic cause of hearing loss is important for accurate genetic counseling and early diagnosis for timely intervention and treatment options. Also, the use of MFPTA in diagnosis of congenital hearing loss as it gives immediate results less expensive and can be done by conventional audiometer

Análisis de las mutaciones más frecuentes del gen BRCA1 (185delAG y 5382insC) en mujeres con cáncer de mama en Bucaramanga, Colombia / Mutations in the BRCA1 gene (185delAG and 5382insC) are not present in any of the 30 breast cancer patients analyzed from eastern Colombia

Introducción. El cáncer de mama es un problema de salud pública a nivel mundial y en Santander es la primera causa de morbimortalidad por cáncer en mujeres. Todo cáncer se considera una enfermedad genética y las mutaciones en los genes BRCA confieren un riesgo de 60% a 80% para el cáncer de mama. Este estudio consistió en buscar las dos mutaciones BRCA1 más frecuentes según la base de datos Breast Cancer Core Information. Objetivo. Determinar la presencia de mutaciones específicas (185delAG, exón 2, y 5382insC, exón 20) en el gen BRCA1 en mujeres con cáncer de mama heredo-familiar, atendidas en los diferentes servicios de oncología de Bucaramanga, Colombia. Materiales y métodos. La muestra incluyó 30 pacientes, de las cuales se obtuvo un consentimiento informado, un cuestionario dirigido y sangre venosa para los estudios moleculares. El análisis molecular se realizó mediante PCR-mismatch, para introducir o eliminar sitios de restricción, y digestión enzimática (HinfI o DdeI). Resultados. No se detectaron dos de las mutaciones más frecuentes en el gen BRCA1 en las 30 pacientes estudiadas. Conclusión. Se requieren más estudios en la región que abarquen la tamización de la totalidad del gen BRCA1, para hacer una mayor contribución al conocimiento de la epidemiología molecular del cáncer de mama en Bucaramanga, Santander, Colombia.

Introduction. Breast cancer is considered a worldwide public health problem, and, in Santander Province, Colombia, it is the first leading cause of morbidity and mortality by cancer in women. All cancers are considered genetic diseases, and mutations in BRCA (BReast CAncer) genes raises the risk for breast cancer by 60%-80%. The current study searched for the two most frequent BRCA1 mutations reported in the Breast Cancer Core Information database.Objective. The presence of specific mutations (185delAG, exon 2 and 5382insC, exon 20) was determined for the BRCA1 gene in women with familial/hereditary breast cancer. Materials and methods. The sample included 30 female patients using the oncology services in Bucaramanga, eastern Colombia; an informed consent, a questionnaire and a blood sample were obtained from each. The molecular analysis was done with PCR-Mismatch, to detect the insertion or eliminatation of a restriction site, and enzymatic digestion methods (HinfI or DdeI).Results. Two of the most frequent BRCA1 mutations in the international database were not found in the 30 patients studied. Conclusion. Additional mutation screening techniques are necessary involving the entire BRCA1 gene, are necessary in order to better characterize the molecular epidemiology of breast cancer in Bucaramanga, Santander, Colombia.

Hypermethylation of the tumor suppressor RASS1A gene in malignant and benign breast tissues from Egyptian patients

Breast cancer is the leading cancer among females. There is a critical need for improved molecular biomarkers that are diagnostic, prognostic and also capable of predicting the progression of benign high-risk lesions to invasive carcinoma. RAS association domain family protein 1A [RASSF1A] gene, is a biologically significant cancer suppressor gene, it is normally unmethylated. It has been chosen to study its methylation status among malignant [50] and benign [40] breast lesions using methylation-specific polymerase chain reaction [MS-PCR]. The relation between the methylation status of RASSF1A gene and different clinicopatho-logical factors data in breast cancer was determined. The current results showed a significant difference between malignant and benign group as regard the methylation status of RASSF1A gene. The methylation of RASSF1A gene was higher in the malignant breast lesions. Considering the relation between RASSF1A hypermethylation and differtent clinicopathological factors, no significant association relation was detected except with late tumor grade, late tumor stage and negative estrogen receptor status. The previous findings indicate that the methylation of RASSF1A gene may be used as a diagnostic or/and prognostic biomarker for breast cancer

Prognostic impact of internal tandem duplications in the juxtamembrane domain of FMS-like tyrosine kinase 3 gene [FLT3-ITDs] in patients with de novo acute myeloid leukemia with favorable karyotypes

Acute myeloid leukemia [AML], refer to a group of marrow-based neoplasms that have clinical similarities but distinct morphologic, immunophenotypic and cytogenetic features. The overall annual incidence is 3.4/100, 000. Affects all age groups. The incidence of AML increases with age, with a median of 68 years. in adults, AML accounts for 80% of cases of acute leukemia, At National Cancer institute, Cairo University; AML accounts for approximately 41.5% [349] out of the 840 newly diagnosed cases with acute leukemia registered in the time period between January 2002 and 2003 [1]. Despite improvement in AML diagnosis and therapeutics, most patients die from relapse, even those with favourable karyotypes. Hence the need for employing, other genetic parameters that can predict risk of relapse. Several studies reported the significance of FLT3 as independent marker for clinical outcome in most AML patients. So we conducted a study to investigate the incidence and prognostic impact of FLT3 mutations multantand the ratio between and wild type FLT3 in patients with de novo AML expressing normal or intermediate risk karyotypes. Our study included 60 subjects with newly diagnosed acute leukemia ranging in age from 18 to 60 years; 32 were males and 28 were females they all presented to the medical oncology clinics, National Cancer Institute, Cairo University, during the time period from January 2005 to December 2007. Analysing the association of FLT3 mutations with FAB subtypes and biological characteristics of the 60 AML patients studied showed that 11 had the FLT3/ITD mutation [18.3%]. The patients ranged in age from 18 to 60 years with a median age of 39.5 years the age of patients at presentation was similar in both groups. There was no statistically significant difference in age and sex between the patients harboring mutations in the FLT3 gene and patients with no FLT3 mutation. The majority of FLT3 mutations were detected in patients with M1 9 of 22 [40.9%], M2 5 of 16[31.3%], M4 2 of 7 [22.2%]. Stratifying patients using FAB classification of AML there was a statistically significant difference between the distribution of FLT3/ITD[+] and FLT3/ITD[-] by FAB classification, where FAB classification in FLT3/ITD[+] cases was [M1:7 patients [31.8%], M2: 4 patients [25%] and in FLT3/ITD[-] cases was [M1 15 patient [68.2%], M2 12 patient [75%], M5, M4, MS and M7 22 patients [100%]]. [P value 0.005]. Statistical comparison of laboratory results between FLT3/ ITD [+] and FLT3/ITD [-] revealed that the percentage of bone marrow blasts at day 15 of treatment between the two groups in patients with FLT3/ITD [+] was 28.36 +/- 32.76% denoting resistance to treatment and lack of response, while in the patients with FLT3/ITD [-] was 6.59 +/- 14.59% with a highly significant difference between the two groups [p value 0.005]. However, no difference was reported between the two groups as regard the percent of blasts in the peripheral blood or bone marrow at presentation. The mean value of HB, WBCs in the peripheral blood, the platelet count between the two groups revealed no significant difference between the two groups. Likewise more patients with FLT3/ITD[-] had remission to treatment at day 15 compared to FLT3/ITD[+] patients, however such difference was not statistically different Also, time to relapse was shorter for patients with FLT3/ITD[+] compared to FLT3/ITD[-] with a statistically significant difference between the two groups [p value 0.00 13] Survival analysis showed the ITD[+] patients had a worse DFS, compared to the FLT3/WT patients [95% confidence interval 0.43-5.57] [p value 0.0013], however the median Survival did not show such effect, with median OS of 4.00 months [95% confidence interval 1.92-6.08] for the ITD+ and 3.00 months [95% confidence interval 0.72-5.28] for FLT3/WT [p-value 0.28]. Our data support the previous studies that FLT3/ITD may be a strong prognostic factor in AML patients. and is associated with a high rate of relapse and lower DFS

Early Onset Renal Failure in Congenital Nephrotic Syndrome associated with Congenital Diaphragmatic Hernia by WT1 Gene Mutation

We experienced a female neonate with congenital nephrotic syndrome (CNS) associated with congenital diaphragmatic hernia (CDH). Because of the rare combination of two conditions, we report this case with literature review. CDH was found immediately after birth and emergency operation was done for hernia repair. But on the next day, generalized edema and oliguria(0.59 mL/kg/hour) was found and her blood chemistry showed hypoalbuminemia (1.6 g/dL), increased BUN (27.7 mg/dL) and serum creatinine( 1.8 mg/dL) along with heavy proteinuria (4+). We started albumin infusion with a bolus of intravenous furosemide. We suspected the neonate had congenital nephrotic syndrome and her 24hr urine protein was 1,816 mg/day. In spite of immunosuppressive therapy, the nephrotic syndrome and renal failure progressed. We started peritoneal dialysis on the day of life 22 but it was not satisfactory. She was complicated by intracranial hemorrhage and multi-organ failure and expired at 34 days of age. Kidney necropsy was performed which showed diffuse mesangial sclerosis (DMS). Her chromosome study revealed 46, XX and her gene study revealed a heterozygous missense mutation, Arg366His, in Wilms tumor suppressor gene (WT1). This case deserves attention on account of the 4th case of CNS with CDH revealing the Arg366His mutation in the WT1 gene andG the 1st case of early onset renal failure without male pseudohermaphroditism and Wilms tumor with CNS, CDH and the Arg366His mutation in the WT1 gene. So, this report gives support to the hypothesis that Arg366His mutation in the WT1 gene can result in CNS and CDH.

Haemochromatosis gene mutation H63D is a risk factor for iron overload in Egyptian beta- thalassemic children

Iron overload is the main cause of morbidity and mortality in patients with beta-thalassemia. The aim of this study was to evaluate the prevalence of genetic markers [HFE mutations C282Y and H63D] among Egyptian beta-thalassemic Children and its effect on their iron status. 59 beta-thalassemic children attending the pediatric hematology clinic in Menoufiya University Hospital [23 thalassemia major, 23 thalassemia intermedia and13 thalassemia trait] with 50 apparently healthy, Egyptian children [control group] were screened for the prevalence of these two mutations by digestion of PCR products [RFLP]. Serum ferritin level was measured by ELISA. Neither carrier status for the C282Y allele nor homozygous status for the H63D allele were detected in any of the thalassemic children or the 50 controls. The H63D heterozygous state was detected in 15 [25.4%] thalassemic patients with an allele frequency of 12.71% and in 11 [22%] controls with an allele frequency of 11%. with no significant difference between the thalassemic groups and the controls. The prevalence of carriers for the H63D mutation was 26.1% with an allele frequency of 13.04% in patients with either beta- thalassemia major or intermedia, while in beta- thalassemia trait the prevalence of this mutation was 23.1% with an allele frequency of 11.54%. There were significant higher levels of the mean yearly serum ferritin in both beta-thalassemia major and intermedia patients who are heterozygotes for the H63D mutation compared to those without this mutation. The mean serum ferritin levels were positively correlated with the age of the patients. On the other hand, the prevalence of iron -induced complications was not statistically different between patients carrying or not carrying this mutation [among TM and TI]. There is no difference in the prevalence of H63D mutation between beta-thalassemic patients and the normal children and the presence of a heterozygous H63D status and older age are two risk factors for iron overload in Egyptian beta-thalassemic children. RFLP= Restriction Fragment Length Polymorphism, HCV=Hepatitis C Virus, ALT = Alanine aminotransferase, AST =Aspartate aminotransferase

Expression of tumor suppressor gene pten in patients with myelodysplastic syndrome and acute myeloid leukemia / 中国实验血液学杂志

To study the expression and significance of pten gene in patients with myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), RT-PCR and Western blot were respectively applied to detect pten mRNA and PTEN protein in Jurkat cells (as negative control), in bone marrow nucleated cells of 35 patients with MDS, 45 patients with AML and 20 normal control. The results showed that pten mRNA expression could not be detected in Jurkat cells, and the positive rate in MDS patients (77.1%) was significantly lower than that in normal control group (90.0%) (p > 0.05), while significant difference was found between AML patients and normal control (60.0% vs 90.0%, p < 0.05); the positive rate in MDS-RAEB patients (70.0%) was lower than that in MDS-RCMD (86.7%); positive rate in de novo and relapsed AML patients (53.3%) was lower than that in AML patients in CR (73.3%), but statistics tests did not show significant difference (p > 0.05). The results of relative expression level of pten mRNA in all groups indicated that both relative expression levels in MDS patients and AML patients were definitely lower than that in normal control group (p < 0.005); the relative expression level in MDS-RAEB patients was lower than that in MDS-RCMD patients (p < 0.05); and in de novo and relapsed AML patients was obviously lower than that in AML patients in CR (p < 0.001). However, there was no significant difference between MDS and AML patients (p > 0.05). The positive rate of PTEN protein expression in both MDS (65.7%) and AML (54.8%) patients were lower than that in normal control (90.0%) (p < 0.05), and there was no significant difference when comparing MDS-RCMD patients (80.0%) with MDS-RAEB patients (55.0%) (p > 0.05), but positive rate of PTEN protein expression in de novo and relapsed AML patients (44.4%) was significantly lower than that in AML patients in CR (73.3%) (p < 0.05). It is concluded that the complete loss of pten mRNA in MDS and AML is uncommon, but the relative expression level in both diseases is significantly lower than that in normal people. The positive rates of PTEN protein expression in both MDS and AML patients are lower, compared with normal people, but are not in accordance with the expression of pten mRNA. The abnormalities of pten gene expression may be involved in the pathogenesis of MDS and AML.

Role of DCC(Deleted in Colorectal Cancer) Gene in Oral Squamous Cell Carcinoma

Chromosome 18q alteration plays a key role in colorectal tumorigenesis, and loss of heterozygosity at 18q is associated with a poor prognosis in colon cancer. DCC(Deleted in Colorectal Cancer) is a putative tumor- suppressor gene at 18q21 that encodes a transmembrane protein with structural similarity to neural cell adhesion molecule that is involved in both epithelial and neuronal cell differentiation. DCC is implicated in regulation of cell growth, survival and proliferation. Thus, tumor progression in squamous cell carcinoma, stomach cancer, colorectal cancer correlates with downregulation of DCC expression. The mechanism for DCC suppression is associated with hypermethylation of the DCC gene promoter region. Hence, the goal of this study is to identify the promoter methylation responsible for the down-regulation of DCC expression in oral squamous cell carcinoma. 12 of tissue specimens for the study are excised and gathered from 12 patients who are diagnosed as SCC in department of OMS, dental hospital, dankook university. To find expression of DCC in each tissue samples, immunohistochemical staining, RT-PCR gene analysis and methylation specific PCR are processed. The results are as follows. 1. In the DCC gene RT-PCR analysis, 5(41.6%) of 12 specimens of oral squamous cell carcinoma did not expressed DCC gene. 2. In the promoter methylation specific PCR analysis, 5(41.6%) of 12 specimens showed promoter methylation of DCC gene. 3. In the immunohistochemical staining of poor differentiated and invasive oral squamous cell carcinoma, loss of DCC expression was observed. These findings suggest that methylation of the DCC gene may play a role in loss of gene expression in invasive oral squamous cell carcinoma.

Fatores moduladores da gravidade da evolução clínica da anemia falciforme / Modifiers factors of clinical severity in sickle cell anemia

A anemia falciforme é considerada uma doença heterogênea com diferentes graus de gravidade clínica apesar de ser causada pela mutação de um único nucleotídeo (Glu6Val) no gene da globina b. A total compreensão desta doença permitirá a descoberta de terapias contra alvos fisiopatológicos específicos. Este artigo revisa alguns dos fatores associados à modulação do fenótipo da anemia falciforme, incluindo fatores eritrocitários e fatores extrínsecos aos eritrócitos.

Sickle cell anemia is a heterogeneous disorder with different degrees of clinical severity despite of being caused by a single base pair mutation (Glu6Val) of the ß-globin gene. Understanding this disease will allow us to discover therapies of specific pathophysiological targets. This article reviews some of the factors that can modulate the phenotype of sickle cell anemia, including red blood cell factors and factors extrinsic to the red blood cells.

Hyperplasia suppressor gene expression in vascular smooth muscle cells derived from normotensive and hypertensive patients underwent bypass surgery / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the novel hyperplasia suppressor gene (HSG) expression in vascular smooth muscle cells derived from normotensive and hypertensive patients underwent bypass surgery.</p><p><b>METHODS</b>Coronary heart disease patients underwent coronary artery bypass graft (CABG) operation in BEIJING ANZHEN hospital from 4 - 9, 2006 were enrolled in this study and divided into hypertensive group (n = 28) and normotensive group (n = 26). The preoperative venous blood samples were taken for serum biochemical and vasoactive peptides measurements. Total RNA was extracted from WBC, explanted-vessels and cultured VSMCs using TRIZOL and HSG expression was determined by Semi-Quantitative RT-PCR.</p><p><b>RESULTS</b>Body mass index (BMI) was significantly higher in hypertensive group compared to normotensive group (P < 0.01) while other biochemic parameters and vasoactive peptides were similar between the groups. BMI and GLU, BMI and SBP, BMI and DBP, GLU and TG, SBP and DBP were positively correlated (all P < 0.05). HSG expression in WBC, VSMCs and vessel tissue were significantly lower in hypertensive group than those in normotensive group (all P < 0.05). HSG expression in tissue was negatively correlated to BMI, SBP and DBP (all P < 0.05).</p><p><b>CONCLUSIONS</b>Reduced HSG expression and the negative correlation on vascular tissue HSG expression to BMI, SBP and DBP suggested a possible inhibitory role of HSG on VSMC proliferation and blood pressure.</p>

O tratamento de LMC com novs inibidres de tirosino-quinases / New TK-inhibitors in chronic myelogenous leukemia

O uso de inibidores do gen de fusao BCR-ABL foi introduzido na prática clínica e o mesilato de imatinibe (MI) se tornou o tratamento de primeira linha na LMC. Porém, um percentual significante de pacientes apresentará resistência primária ou adquirida. Desse modo, novas drogas têm sido desenvolvidas no sentido de superar a resistência ao MI. Dasatinibe e nilotinibe têm demonstrado importância prática. Outros inibidores de TK, principalmente para superar a mutação T3151 estão em desenvolvimento.

The use of BCR-ABL fusion gene was introduced in clinical practice and the imatinib mesylate (IM) became the front line therapy for CML. However, a significant percentage of patients will present primary or acquire resistence. News drugs have been developed in order to overcome resistant to IM. Datatinib and nilotinib demonstrated to be very active and have been introduced in clinical practice. Other TK inhibitors mainly to overcome resistance to T3151I mutation are currently in development.

Crianças portadoras de neurofibromatose tipo 2: o pediatra geral pode reconhecer esta entidade? / Children with neurofibromatosis type 2: can the general pediatrician recognize this entity?

A neurofibromatose tipo 2 é uma desordem autossômica dominante causada pela inativação ou perda de ambos os alelos do gene supressor de tumor NF2. Neste artigo estão sumarizados a epidemiologia, genética características clínicas, e os critérios para avaliar e diagnosticar o quadro nas pessoas de risco...

Comparison of PCR-RFLP and Real-Time PCR for Allelotyping of Single Nucleotide Polymorphisms of RRM1, a Lung Cancer Suppressor Gene / 결핵및호흡기질환

BACKGROUND: Single nucleotide polymorphisms (SNPs), which consist of a substitution of a single nucleotide pair, are the most abundant form of genetic variations occurring with a frequency of approximately 1 per 1000 base pairs. SNPs by themselves do not cause disease but can predispose humans to disease, modify the extent or severity of the disease or influence the drug response and treatment efficacy. Single nucleotide polymorphisms (SNPs), particularly those within the regulatory regions of the genes often influence the expression levels and can modify the disease. Studies examining the associations between SNP and the disease outcome have provided valuable insight into the disease etiology and potential therapeutic intervention. Traditionally, the genotyping of SNPs has been carried out using polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP), which is a low throughput technique not amenable for use in large-scale SNP studies. Recently, TaqMan real-time PCR chemistry was adapted for use in allelic discrimination assays. This study validated the accuracy and utility of real-time PCR technology for SNPs genotyping METHODS: The SNPs in promoter sequence (-37 and -524) of lung cancer suppressor gene, RRM1 (ribonucleotide reductase M1 subunit) with the genomic DNA samples of 89 subjects were genotyped using both real-time PCR and PCR-RFLP. RESULTS: The discordance rates were 2.2% (2 mismatches) in -37 and 16.3% (15 mismatches) in -524. Auto-direct sequencing of all the mismatched samples(17 cases) were in accord with the genotypes read by real-time PCR. In addition, 138 genomic DNAs were genotyped using real-time PCR in a duplicate manner (two separated assays). Ninety-eight percent of the samples showed concordance between the two assays. CONCLUSION: Real-time PCR allelic discrimination assays are amenable to high-throughput genotyping and overcome many of the problematic features associated with PCR-RFLP.