RESUMO
INTRODUCCIÓN El linfoma de células del manto (LCM) es una neoplasia linfoide de células B correspondiente a alrededor del 7% de los linfomas no-Hodgkin. Los genes SOX4, SOX11 y SOX12 integran la familia SOXC involucrada en la neurogénesis embrionaria y el remodelado tisular. Entre ellos, SOX11 muestra expresión aberrante en LCM y se considera como un marcador molecular de pronóstico adverso. Diferentes estudios han mostrado un rol oncogénico del clúster miR17-92: miR17, miR18, miR19 y miR92 en neoplasias hematológicas, y hay escasa información sobre su asociación con LCM. OBJETIVOS Analizar los perfiles de expresión génica de los genes SOXC y su correlación con la expresión de los miembros del clúster miR-17-92 miR17, miR18, miR19 y miR92, en pacientes con LCM. MÉTODOS Se analizaron biopsias incluidas en parafina de 45 pacientes con LCM mediante PCR en tiempo real con metodología TaqMan, y 12 controles. Se evaluó el índice de proliferación con el marcador Ki67 por inmunohistoquímica. RESULTADOS Se detectó un aumento significativo de la expresión génica de SOX11 y SOX12 (2,1±0,24 y 3,1±0,16, respectivamente) respecto de SOX4 (1,2±0,21) (p=0,006 y p<0,0001, respectivamente), con una relación inversa entre los niveles de SOX11 y SOX4 (p=0,0017), siendo este último nulo en los pacientes con mayor expresión de SOX11. El análisis del clúster miR-17-92 mostró un aumento de expresión en miR19a (3,24±0,1) y miR92a (2,59±0,1) respecto de miR17 (-2,7±0,15) y miR18a (-2,8±0,19) (p<0,0001), así como una correlación positiva de miR92a con los restantes genes de este clúster (p<0,0013). Se halló una correlación positiva entre la expresión del clúster SOXC y miR18 (p<0,012). DISCUSIÓN Estos datos muestran por primera vez una correlación inversa entre la expresión de SOX11 y SOX4, así como una expresión diferencial de los genes SOXC y miR18, lo que sugiere una interacción de probable importancia biológica en LCM.
Assuntos
Expressão Gênica , Linfoma de Célula do MantoRESUMO
Chromosome abnormalities detected in metaphases from multiple myeloma (MM) cells have a clear impact on prognosis and response to therapy. Thirteen out of 50 (26%) patients with plasma cell disorders and abnormal karyotypes (11 with MM and 2 with plasma cell leukemia (PCL)) were selected for inclusion in the present report based on the presence of karyotypes with new and/or infrequent structural aberrations. Thirty-three new rearrangements, including a novel recurrent aberration: psu dic(5;1)(q35;q10), were detected. Chromosome 1 was the most frequently involved. Gains of genetic material (57%) were noted more frequently than losses (43%). Three rearrangements that were observed only once in the literature appear to be recurrent from our data: del(16)(q13), del(5)(p13) and i(3)(q10), the latter being a single structural aberration in the karyotype. Clinical parameters from our series were compared with 2 control groups: 20 MM cases with recurrent aberrations in MM/PCL with a similar distribution of abnormalities associated with poor prognosis (group 1), and 40 with normal karyotypes and fluorescence in situ hybridization analysis (group 2). Significantly increased serum calcium levels (p = 0.022) in patients with new and/or infrequent chromosome changes with respect to both control groups, and a higher percentage of bone marrow plasma cell infiltration (p = 0.005), ß(2) microglobulin, and lactate dehydrogenase levels (p < 0.0001) compared to group 2 were observed. Our results suggest that some of these novel rearrangements may be capable to deregulate genetic mechanisms related to the development and/or progression of the disease. The finding of new recurrent aberrations supports this hypothesis.
Assuntos
Aberrações Cromossômicas , Leucemia Plasmocitária/genética , Mieloma Múltiplo/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Cálcio/sangue , Cromossomos Humanos Par 1/genética , Cromossomos Humanos Par 16/genética , Cromossomos Humanos Par 3/genética , Cromossomos Humanos Par 5/genética , Feminino , Humanos , Hibridização in Situ Fluorescente , Cariotipagem , Leucemia Plasmocitária/sangue , Leucemia Plasmocitária/patologia , Masculino , Pessoa de Meia-Idade , Mieloma Múltiplo/sangue , Mieloma Múltiplo/patologia , PrognósticoRESUMO
Los telómeros son estructuras esenciales para el mantenimiento de la integridad cromosómica y la capacidad replicativa de la célula. La reducción de la longitud telomérica (LT) aumenta la probabilidad de producir errores capaces de generar cambios genómicos importantes para el desarrollo neoplásico, determinando desbalances de material genético. En este trabajo se evaluó la LT mediante el análisis de fragmentos de restricción terminal (TRF) en médula ósea y/o biopsia ganglionar de 36 pacientes (edad media: 54.2 años; rango 29-77 años; 21 varones): 29 con linfoma folicular (LF) al diagnóstico y 7 con linfoma B difuso a células grandes secundario a LF (LBDCG-S). Se efectuó el análisis del rearreglo molecular del gen BCL-2 por PCR anidada y de larga distancia. Las medias de TRF en LF (4.18±0.18 Kb) y LBDCG-S (3.31±0.25 Kb) resultaron significativamente menores que en controles (8.50±0.50 Kb) (p<0.001), encontrándose diferencias entre ambos subtipos histológicos (p=0.036). Las muestras negativas para el rearreglo BCL-2 mostraron LT menores (3.39±0.30 Kb) que las positivas (4.25±0.19 Kb) (p=0.023), observándose una tendencia a valores menores en pacientes negativos para el rearreglo BCL-2, intermedios en positivos para mcr, minor cluster region, (3.84±0.45 Kb) y mayores en los positivos para MBR, Major Breakpoint Region, (4.35±0.21 Kb). Nuestros resultados muestran una reducción de la LT en LF y LBDCG-S, con TRFs significativamente más cortos en estos últimos, sugiriendo la participación del acortamiento telomérico em la progresión tumoral. Asimismo, las diferencias detectadas entre los casos BCL-2 positivos y negativos sustentarían la presencia de diferentes mecanismos patogénicos propuestos para estos distintos LF.
Assuntos
Adulto , Pessoa de Meia-Idade , Humanos , Masculino , Feminino , Linfoma Difuso de Grandes Células B , Linfoma de Células B/genética , Linfoma Folicular/genética , Telômero/fisiologia , Medula Óssea/patologia , Gânglios/patologia , /genética , Telômero/genéticaRESUMO
Los telómeros son estructuras esenciales para el mantenimiento de la integridad cromosómica y la capacidad replicativa de la célula. La reducción de la longitud telomérica (LT) aumenta la probabilidad de producir errores capaces de generar cambios genómicos importantes para el desarrollo neoplásico, determinando desbalances de material genético. En este trabajo se evaluó la LT mediante el análisis de fragmentos de restricción terminal (TRF) en médula ósea y/o biopsia ganglionar de 36 pacientes (edad media: 54.2 años; rango 29-77 años; 21 varones): 29 con linfoma folicular (LF) al diagnóstico y 7 con linfoma B difuso a células grandes secundario a LF (LBDCG-S). Se efectuó el análisis del rearreglo molecular del gen BCL-2 por PCR anidada y de larga distancia. Las medias de TRF en LF (4.18±0.18 Kb) y LBDCG-S (3.31±0.25 Kb) resultaron significativamente menores que en controles (8.50±0.50 Kb) (p<0.001), encontrándose diferencias entre ambos subtipos histológicos (p=0.036). Las muestras negativas para el rearreglo BCL-2 mostraron LT menores (3.39±0.30 Kb) que las positivas (4.25±0.19 Kb) (p=0.023), observándose una tendencia a valores menores en pacientes negativos para el rearreglo BCL-2, intermedios en positivos para mcr, minor cluster region, (3.84±0.45 Kb) y mayores en los positivos para MBR, Major Breakpoint Region, (4.35±0.21 Kb). Nuestros resultados muestran una reducción de la LT en LF y LBDCG-S, con TRFs significativamente más cortos en estos últimos, sugiriendo la participación del acortamiento telomérico em la progresión tumoral. Asimismo, las diferencias detectadas entre los casos BCL-2 positivos y negativos sustentarían la presencia de diferentes mecanismos patogénicos propuestos para estos distintos LF. (AU)
Assuntos
Adulto , Pessoa de Meia-Idade , Idoso , Humanos , Masculino , Feminino , RESEARCH SUPPORT, NON-U.S. GOVT , Telômero/fisiologia , Linfoma Folicular/genética , Linfoma Difuso de Grandes Células B/genética , Linfoma de Células B/genética , Telômero/genética , Genes bcl-2/genética , Gânglios/patologia , Medula Óssea/patologiaRESUMO
Telomeres are specialized structures at the ends of eukaryotic chromosomes, composed of tandem repeats of a repetitive DNA sequence (TTAGGG)n and associated proteins. They have a number of important functions including the protection of chromosomes from end-to-end fusion and degradation. When telomeres become critically short, telomere separation in mitosis cannot be performed properly leading to metaphase telomeric associations (tas) and chromosome instability. This instability can be relevant for neoplastic transformation because it increases the probability of errors that can generate genetic changes critical in the multistep process of transformation, like gene amplification and loss of heterozygosity. The mechanisms involved in tas are unknown, but it could be because of failure in the enzymatic activity of telomerase, a ribonucleoprotein enzyme with an RNA template that directs synthesis of telomeric repeats at chromosome extremities, producing telomeric length stabilization. A progressive telomere shortening with ageing has been shown to occur both in vitro and in vivo. Recent studies have shown an association between the presence of tas and telomeric shortening, and also a correlation between telomere reduction and increased telomerase activity in both solid tumors and hematologic malignancies. The evidence that most human malignancies have telomerase activity would indicate that telomerase could be a prevalent and specific tumor marker, and thus may be a novel and excellent target for anti-cancer therapy.
Assuntos
Transformação Celular Neoplásica/metabolismo , Senescência Celular/fisiologia , Proteínas de Neoplasias/metabolismo , Neoplasias/enzimologia , Telomerase/metabolismo , Telômero/enzimologia , Neoplasias Hematológicas/enzimologia , Humanos , Neoplasias/etiologiaRESUMO
Telomeres are specialized structures at the ends of eukaryotic chromosomes, composed of tandem repeats of a repetitive DNA sequence (TTAGGG)n and associated proteins. They have a number of important functions including the protection of chromosomes from end-to-end fusion and degradation. When telomeres become critically short, telomere separation in mitosis cannot be performed properly leading to metaphase telomeric associations (tas) and chromosome instability. This instability can be relevant for neoplastic transformation because it increases the probability of errors that can generate genetic changes critical in the multistep process of transformation, like gene amplification and loss of heterozygosity. The mechanisms involved in tas are unknown, but it could be because of failure in the enzymatic activity of telomerase, a ribonucleoprotein enzyme with an RNA template that directs synthesis of telomeric repeats at chromosome extremities, producing telomeric length stabilization. A progressive telomere shortening with ageing has been shown to occur both in vitro and in vivo. Recent studies have shown an association between the presence of tas and telomeric shortening, and also a correlation between telomere reduction and increased telomerase activity in both solid tumors and hematologic malignancies. The evidence that most human malignancies have telomerase activity would indicate that telomerase could be a prevalent and specific tumor marker, and thus may be a novel and excellent target for anti-cancer therapy.
RESUMO
Translocation t(14; 18) has been observed in 50-85% of follicular and in 30% of diffuse non-Hodgkin lymphomas. About half of follicle center lymphoma (FCL) undergo histological conversion at relapse to more aggressive diffuse large B-cell lymphoma (DLBCL). This report correlates the molecular bcl-2/IgH rearrangement by PCR and Bcl-2 immunohistochemical (IHC) expression in a series of high grade DLBCLs with and without FCL remnant. Twenty-three paraffin-embedded lymph nodes from DLBCL patients were analyzed. Eleven patients showed FCL remnant (Group A) and 12, did not (Group B). Single PCR from paraffin extracted DNA followed by Southern transfer of products, hybridisation with internal oligoprobes for the MBR/JH and MCR/JH bcl-2 rearrangements and IHC analysis of Bcl-2 expression, were performed. PCR analysis was positive in 34.8% of patients. Bcl-2/IgH gene rearrangements were observed in 8 (34%) cases and 7 (30%) showed Bcl-2 expression on large noncleaved B-cells (centroblasts). All patients from Group A showed IHC positive reaction on FCL remnant (small cleaved cells) but only 2 (18%) were positive in DLBCL areas, suggesting either the loss of the bcl-2 expression on the transformed lymphoma, or, alternatively, the development of a second disease when the first lymphoma transforms. Group B patients showed a clear correlation between PCR and IHC studies. Our results suggest a similar frequency of t(14; 18) in DLBCLs to that reported in Europe and USA series. The discordance observed between PCR and IHC, particularly in Group A, points out the necessity to perform both studies in order to detect bcl-2 gene involvement in DLBCLs.
Assuntos
Genes bcl-2/genética , Linfoma Difuso de Grandes Células B/genética , Adulto , Idoso , DNA de Neoplasias/análise , Feminino , Rearranjo Gênico do Linfócito B , Humanos , Linfoma Difuso de Grandes Células B/patologia , Masculino , Pessoa de Meia-Idade , Análise de Sequência com Séries de Oligonucleotídeos , Inclusão em Parafina , Reação em Cadeia da PolimeraseRESUMO
OBJECTIVE: Chromosome instability provides a predisposing background to malignancy, contributing to the crucial genetic changes in multistep carcinogenesis. The aim of this work was to analyze chromosome instability in patients with ulcerative colitis (UC) to achieve a better understanding of the increased risk for colorectal cancer. METHODS: Peripheral blood lymphocyte cultures from 20 untreated UC patients and 24 controls were used to study chromosome instability by assessing telomeric associations (TAS), chromosome aberrations (CA), and sister chromatid exchanges (SCE). RESULTS: Mean frequencies of TAS and CA were significantly increased in UC patients compared to controls (p < 0.001). Chromosomes 10, 11, 21, 16, and 19 were the most frequently involved in TAS. A total of 104 CA clustered in 66 breakpoints could be exactly localized. Seven nonrandom bands significantly affected in UC patients were found (p < 0.004), showing a significant correlation with the location of cancer breakpoints (p < 0.003), particularly with colorectal carcinoma rearrangements. SCE analysis showed higher levels in patients compared to controls (p < 0.006), but no differences were observed in cell cycle kinetics. CONCLUSIONS: Our results demonstrate the presence of an unstable genome in UC patients that could be related to the cancer development observed in this disease.
Assuntos
Aberrações Cromossômicas/genética , Colite Ulcerativa/genética , Frequência do Gene/genética , Troca de Cromátide Irmã/genética , Telômero/genética , Adolescente , Adulto , Idoso , Biópsia , Ciclo Celular/genética , Células Cultivadas , Colite Ulcerativa/complicações , Colite Ulcerativa/patologia , Colonoscopia , Neoplasias Colorretais/etiologia , Neoplasias Colorretais/genética , Feminino , Marcadores Genéticos , Predisposição Genética para Doença , Humanos , Masculino , Pessoa de Meia-Idade , Telômero/ultraestruturaRESUMO
Intron 22 factor VIII gene inversion (Inv22) is the most common mutation causing severe haemophilia A (SHA). We studied Inv22 in 34 SHA affected families by Southern blotting. Data from the familial history of the disease and the inhibitor status were also included. We found Inv22 in 41 % of SHA Argentine families (35 % with type 1 and 6 % with type 2), in close agreement with previously reported series. No significant correlation between the inheritance (familiar or sporadic disease) and the presence of inversions was found. Our population showed 24 % of families included at least one hemophiliac with inhibitor. In families positive for Inv22, 29 % of patients developed inhibitor but this increased frequency was not statistically significant. In conclusion, analysis of Inv22 in SHA patients should be used as a first line method because it provides useful and secure information for carrier detection and prenatal diagnosis in a high percentage of cases.
Assuntos
Inversão Cromossômica , Fator VIII/genética , Hemofilia A/genética , Íntrons/genética , Argentina/epidemiologia , Southern Blotting , Sondas de DNA , Fator VIII/imunologia , Saúde da Família , Feminino , Frequência do Gene , Hemofilia A/epidemiologia , Hemofilia A/imunologia , Humanos , Isoanticorpos/sangue , Masculino , Polimorfismo de Fragmento de RestriçãoRESUMO
In the current study we analyzed chromosome instability on peripheral blood lymphocytes cultured from 7 untreated patients with chronic pancreatitis (CP) by assessing telomeric associations (TAS), chromosome aberrations (CA) and sister chromatid exchanges (SCE). Seven healthy individuals were also analyzed. Mean frequencies of TAS were significantly higher in CP patients (X +/- SE: 11.00 +/- 2.37) compared to controls (1.00 +/- 0.30) (p<0.001). Chromosomes preferentially involved in TAS were: 9, 20, 16 and 21, being the most affected arms: 9p, 20q, 16p, 9q and 21q. All these terminal bands were coincident with cancer breakpoints (p<0.03), two of them (40%) were specifically associated to pancreatic carcinoma rearrangements. Three bands (60%) were coincident with oncogene location. The mean frequency of CA was significantly higher in patients (3.88 +/- 0.80) compared to controls (0.63 +/- 0.49) (p<0.001). Chromosomes 1, 2 and 13 were the most damaged. No specifically affected breakpoints were found. SCE analysis showed higher levels in patients (8.33 +/- 0.70) than in controls (6.62 +/- 0.34) (p<0.025), but no differences were observed in cell cycle kinetics. Our results clearly indicate that CP patients exhibit chromosome instability, showing the presence of an unstable genome that could be related to the cancer development observed in this disease.