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1.
Rev. esp. patol ; 37(2): 159-172, abr. 2004. ilus, tab
Artigo em Es | IBECS | ID: ibc-37535

RESUMO

El linfoma de células del manto (LCM) es un subtipo de linfoma no Hodgkin de fenotipo B que representa entre un 2'5 y un 10 por ciento de todos los linfomas. Histológicamente puede presentar un patrón de crecimiento en la zona del manto, nodular o difuso y se diferencian dos variedades, típica y blastoide. Clínicamente, suele presentarse en varones de edad avanzada, de forma diseminada y con frecuente afección extranodal. Fenotípicamente se caracteriza por la presencia de una población monoclonal de línea B con positividad para CD5 y sobreexpresión de ciclina D1asociada a la presencia constante de la translocación t(11;14). En las formas típicas y blastoides se han identificado frecuentemente alteraciones en el gen ATM. Las formas blastoides presentan además alteraciones genéticas adicionales que incluyen inactivación de los genes supresores tumorales p53 y p16INK4a. La supervivencia media de LCM oscila entre 3 y 5 años (AU)


Assuntos
Humanos , Linfoma de Célula do Manto/genética , Antígenos CD5/sangue , Genes p53/genética , Genes p16/genética , Ciclina A/genética , Gânglios/patologia , Imunofenotipagem/métodos , Diagnóstico Diferencial
2.
Neurology ; 57(7): 1278-81, 2001 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-11591848

RESUMO

OBJECTIVE: To identify different genetic molecular profiles in oligodendrogliomas and to evaluate their prognostic significance. METHODS: The main genetic alterations reported in glial tumors were investigated in 26 oligodendrogliomas (10 World Health Organization grade II and 16 World Health Organization grade III). Correlation between identified molecular changes and pathologic grade or clinical course was subsequently analyzed using univariate and multivariate statistical analyses. RESULTS: Loss of heterozygosity (LOH) on chromosome 1p, 19q, and 10; P16/CDKN2A homozygous deletion; EGFR (epidermal growth factor receptor) amplification; and TP53 and PTEN mutations were observed in 14 (54%), 15 (58%), 9 (35%), 7 (27%), 5 (19%), 1 (4%), and 0 cases. LOH 1p and 19q were tightly associated (p < 0.0001). A mutual exclusion was found between LOH 1p/19q and EGFR amplification (p = 0.01), P16/CDKN2A deletions (p = 0.001), or LOH on 10q (p = 0.03), suggesting the existence of distinct genetic subsets in oligodendrogliomas. On univariate analysis, age <50 years (p = 0.002) and LOH 1p (p = 0.01) were associated with a longer progression-free survival (PFS) whereas LOH 10q (p = 0.03) and EGFR amplification (p = 0.007) were associated with a worse PFS. In multivariate analyses, age <50 years (p = 0.001) and LOH 1p (p = 0.006) remained independent predictive factors for PFS. CONCLUSION: These results provide evidence for two alternative molecular pathways of progression in oligodendrogliomas. The first one is associated with loss of 1p and 19q and the second one with P16/CDKN2A deletion, 10q loss, and EGFR amplification. The findings confirm the value of loss of 1p as predictor of longer progression-free survival; in addition, the study demonstrates the unfavorable impact of 10q loss and EGFR amplification on the prognosis.


Assuntos
Neoplasias Encefálicas/genética , Neoplasias Encefálicas/mortalidade , Heterogeneidade Genética , Oligodendroglioma/genética , Oligodendroglioma/mortalidade , Proteínas Supressoras de Tumor , Adulto , Idoso , Neoplasias Encefálicas/patologia , Cromossomos Humanos Par 1 , Cromossomos Humanos Par 10 , Cromossomos Humanos Par 19 , Progressão da Doença , Intervalo Livre de Doença , Receptores ErbB/genética , Genes p16/genética , Genes p53/genética , Humanos , Perda de Heterozigosidade , Pessoa de Meia-Idade , Análise Multivariada , Oligodendroglioma/patologia , PTEN Fosfo-Hidrolase , Monoéster Fosfórico Hidrolases/genética , Valor Preditivo dos Testes , Prognóstico
3.
J Vet Med A Physiol Pathol Clin Med ; 48(6): 365-71, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11554494

RESUMO

Regions of the promoter and exons 5-8 of the tumour suppressor gene p53 were analysed in 25 cases of sporadic bovine leucosis. The study included 17 cases of juvenile leucosis, five cases of adult leucosis and three cases of skin leucosis. Exon 2 of tumour suppressor gene p16 was also investigated in the same samples. No sequence variations were present in the analysed areas of the genes. In p53, this fact represents a clear difference in comparison with enzootic bovine leucosis. In p16, no comparative data are available.


Assuntos
Leucose Enzoótica Bovina/genética , Genes p16/genética , Genes p53/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Bovinos , Infecções por Deltaretrovirus/genética , Infecções por Deltaretrovirus/veterinária , Éxons/genética , Dados de Sequência Molecular , Mutação , Regiões Promotoras Genéticas/genética
4.
Am J Pathol ; 159(3): 1129-35, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11549606

RESUMO

Methylation of cytosines in CpG islands silences gene expression. CpG island methylator phenotype (CIMP) in colorectal cancers is characterized by abnormal methylation of multiple CpG islands including those in several tumor suppressor genes such as p16, hMLH1, and THBS1. CpG island methylation has not been well characterized in adenomas. We evaluated methylation status at p16, MINT2, and MINT31 loci, which are frequently methylated in colorectal carcinomas, in 108 colorectal adenomas from a prospective study of 50 patients without cancer. Methylation at one or more loci was present in 48% (52 of 108) of adenomas with 25% (19 of 76) CIMP-high (two or more methylated loci) and 32% (24 of 76) CIMP-low (one methylated locus). The p16 gene was methylated in 27% (19 of 71) of adenomas. Methylation status of different adenomas from the same patient was not correlated (odds ratio, 0.93; P = 0.77). Adenomas with tubulovillous or villous histology were frequently methylated: 73% (17 of 26) versus 41% (35 of 85) of tubular adenomas (odds ratio, 3.46; P = 0.02). High levels of microsatellite instability were more frequent in adenomas without methylation (13% versus 2%; odds ratio, 8.48; P = 0.05). Our results indicate that methylation plays an important role early in colorectal tumorigenesis. CpG island methylation is more common in adenomas with tubulovillous/villous histology, a characteristic associated with more frequent predisposition to invasive carcinoma. Methylation is distinct from microsatellite instability and develops in individual adenomas rather than resulting from a field defect in an individual patient.


Assuntos
Adenoma/genética , Caderinas , Neoplasias Colorretais/genética , Ilhas de CpG/genética , Metilação de DNA , Idoso , Proteínas de Transporte/genética , Feminino , Genes p16/genética , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas do Tecido Nervoso/genética
5.
Int J Oncol ; 19(4): 749-53, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11562750

RESUMO

Mutational inactivation of the cyclin-dependent kinase inhibitors (CDKIs) (p16CDKN2a) tumor suppressor gene has been found in a variety of human tumor types. To investigate the involvement of CDKI abnormality in clear cell chondrosarcoma, alterations of CDKIs were examined in clear cell chondrosarcoma tissues using a quantitative DNA/PCR, PCR-SSCP. Two of 38 specimens (5.2%) we analyzed showed abnormally low levels of p16CDKN2a amplification, suggesting that the allelic deletion of the gene might be low frequent event in progression of this tumor. For detection of subtle sequence alterations such as point mutations, we performed SSCP analysis of the entire coding region of the p16CDKN2a gene. No altered SSCP patterns were found in 38 clear cell chondrosarcoma specimens. This study reflects the very low incidence of genetic alterations of the p16CDKN2a gene in clear cell chondrosarcoma. Therefore, we conclude that the alteration of the p16CDKN2a gene is not involved significantly in the development of clear cell chondrosarcoma.


Assuntos
Neoplasias Ósseas/genética , Condrossarcoma/genética , Genes p16/genética , Mutação/genética , Neoplasias Ósseas/metabolismo , Condrossarcoma/metabolismo , Análise Mutacional de DNA , Primers do DNA/química , DNA de Neoplasias/análise , Eletroforese em Gel de Poliacrilamida , Humanos , Reação em Cadeia da Polimerase , Polimorfismo Conformacional de Fita Simples
7.
Br J Cancer ; 85(4): 527-30, 2001 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-11506491

RESUMO

One of the most common melanoma-related CDKN2A mutations reported in North America is the V126D mutation. We examined nine markers surrounding CDKN2A in three American and four Canadian families carrying the V126D mutation. All seven families had a haplotype consistent with a common ancestor/founder for this mutation. In addition, the mutation appears to have originated 34-52 generations ago (1-LOD-unit support interval 13-98 generations).


Assuntos
Efeito Fundador , Genes p16/genética , Predisposição Genética para Doença , Melanoma/genética , Neoplasias Cutâneas/genética , Canadá , Análise Mutacional de DNA , Humanos , Melanoma/patologia , Linhagem , Neoplasias Cutâneas/patologia , Estados Unidos
8.
Cancer Res ; 61(16): 6008-11, 2001 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-11507043

RESUMO

The helix-loop-helix transcription factor Id1 coordinates cell growth and differentiation pathways within mammalian cells and has been implicated in regulating G(1)-S phase cell cycle transitions. Recently Id1 has been shown to repress Ets- and E-protein-mediated transactivation of p16/Ink4a. Because the p16/Ink4a protein has been demonstrated to be inactivated in subsets of familial and sporadic melanomas, we sought to determine whether Id1 regulation of p16/Ink4a expression might be involved in the development of this human tumor. Here we evaluate 21 melanocytic lesions at various stages of malignant progression from common melanocytic nevi to metastatic melanomas and examine these lesions for Id1 and p16/Ink4a expression. We demonstrate that Id1 expression correlates with loss of p16/Ink4a expression in melanoma in situ; however, more advanced stages of melanoma do not express Id1 except within perivascular regions, despite overall decreased p16/Ink4a expression in these lesions. Microdissected lesions were evaluated for p16/Ink4a sequence, and invasive melanomas that did not express Id1 were found to have sustained inactivating p16/ink4a mutations. These data suggest a role for Id1 in regulating p16/Ink4a expression in early melanomas and demonstrate that later genetic changes may provide for irreversible loss of p16 expression in advanced stages of this tumor.


Assuntos
Proteínas de Ligação a DNA/fisiologia , Regulação Neoplásica da Expressão Gênica/fisiologia , Genes p16/genética , Melanoma/genética , Proteínas Repressoras , Fatores de Transcrição/fisiologia , Inibidor p16 de Quinase Dependente de Ciclina/biossíntese , Inibidor p16 de Quinase Dependente de Ciclina/genética , Proteínas de Ligação a DNA/biossíntese , Proteínas de Ligação a DNA/genética , Humanos , Proteína 1 Inibidora de Diferenciação , Melanoma/metabolismo , Melanoma/patologia , Estadiamento de Neoplasias , Análise de Sequência de DNA , Fatores de Transcrição/biossíntese , Fatores de Transcrição/genética , Regulação para Cima
9.
J Urol ; 166(3): 1088-92, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11490304

RESUMO

PURPOSE: Loss of various loci on chromosome 9 has been reported in various cancers. To determine the frequency of deletions at different loci of chromosome 9 in renal cell carcinoma microdissected samples of normal renal epithelium and carcinoma from the same patients were analyzed. MATERIALS AND METHODS: DNA was isolated from microdissected sections of normal and tumor cells of 60 renal specimens, amplified by polymerase chain reaction and analyzed for loss of heterozygosity on chromosome 9 using the 16 microsatellite markers D9S178, D9S157, D9S274, D9S168, D9S285, D9S156, D9S1839, D9S162, IFNA, D9S736, D9S171, D9S1749, D9S273D9S270, D9S153 and D9S170. Loss of heterozygosity was analyzed by a polymerase chain reaction based technique developed at our laboratory. RESULTS: This study showed a high incidence of loss of heterozygosity on chromosome 9 in renal cell carcinoma. Of 60 cases 44 (73%), 24 (40%) and 14 (23%) showed loss of heterozygosity at a minimum of 1, at a minimum of 3 and at 4 or more loci, respectively. The main deletion was found on the 9p21 region at loci DS171 in 38% of cases, D9S1749 in 42% and DS270 in 14%. Overall deletion on chromosome 9p21 was noted in 57% of renal cancer cases. Other deleted regions were on chromosome 9p'0022 to 23 at loci D9S157 in 37% of cases, D9S274 in 20%, D9S168 in 27%, D9S285 in 20%, D9S156 in 12%, D9S1839 in 17% and D9S162 in 24%. Overall deletion at chromosome 9q32 to 33 was noted in 46% of renal cell carcinoma cases. Chromosome 9q32 to 33 also showed deletion at locus D9S170 in 22% of renal cell carcinoma cases. When we compared the incidence of deletion at various loci on chromosome 9 according to renal cell carcinoma grade, we found a higher rate of deletion in advanced grades of renal cell carcinoma. A candidate target tumor suppressor gene, p16 (MTS-1/CDKN2), has been identified within the 9p21 deleted region in various cancers. In our study the expression of p16 protein was absent or low in renal cell cancer samples, suggesting that loss of the p16 gene may be involved in renal cell carcinogenesis. CONCLUSIONS: Our study demonstrates a high incidence of loss of heterozygosity on chromosome 9, mainly 9p21 and 9p22 to 23, in renal cell carcinoma, suggesting several putative tumor suppressor genes on these regions. The identification of other tumor suppressor genes on the 9p21 and 9p22 to 23 regions warrants further studies.


Assuntos
Carcinoma de Células Renais/genética , Cromossomos Humanos Par 9/genética , Deleção de Genes , Genes Supressores de Tumor , Neoplasias Renais/genética , Mapeamento Cromossômico , Genes p16/genética , Humanos , Perda de Heterozigosidade , Repetições de Microssatélites
11.
Cancer Res ; 61(15): 5905-10, 2001 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-11479232

RESUMO

Functional inactivation of the Rb and p53 pathways appears to be a rite of passage for all cancerous cells. However, p53 and Rb alterations are rare events in neuroendocrine gastroenteropancreatic (GEP) tumors. The CDKN2 locus on chromosome 9p21 sits at the nexus of both pathways harboring tumor suppressor genes, which restrain cell growth by affecting the function of pRb and p53. Therefore, we analyzed the implication of their inactivation in 37 primary neuroendocrine GEP tumors and two cell culture models. RT-PCR analysis revealed loss of expression of at least one of the tumor suppressor genes CDKN2A/p16, CDKN2B/p15, and CDKN2D/p14 with distinct genetic profiles, most frequently in nonfunctional pancreatic tumors (57%) and small intestinal carcinoids (44%), and less commonly in insulinomas (30%) and gastrinomas (22%). DNA analysis and methylation-specific PCR attributed loss of expression to either homozygous deletion or 5'CpG island hypermethylation. 5-Aza-2-deoxycytidine treatment reversed CDKN2A/p16 and CDKN2B/p15 silencing with concurrent growth restraint. Thus, tumor suppressor genes localized in the 9p21 gene cluster are specific targets of inactivation in neuroendocrine GEP tumors, and demethylating agents might hold promise for selective therapy.


Assuntos
Proteínas de Ciclo Celular , Cromossomos Humanos Par 9/genética , Inibidor p16 de Quinase Dependente de Ciclina , Neoplasias Gastrointestinais/genética , Genes Supressores de Tumor/genética , Família Multigênica/genética , Tumores Neuroendócrinos/genética , Neoplasias Pancreáticas/genética , Proteínas Supressoras de Tumor , Proteínas de Transporte/genética , Divisão Celular/genética , Aberrações Cromossômicas , Inibidor de Quinase Dependente de Ciclina p15 , Inibidor de Quinase Dependente de Ciclina p19 , Metilação de DNA , Neoplasias Gastrointestinais/patologia , Regulação Neoplásica da Expressão Gênica , Inativação Gênica , Genes p16/genética , Humanos , Tumores Neuroendócrinos/patologia , Neoplasias Pancreáticas/patologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa
12.
Nucleic Acids Res ; 29(16): 3335-46, 2001 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-11504871

RESUMO

The mts1/S100A4 gene encodes a small acidic calcium-binding protein that is expressed in a cell-specific manner in development, tumorigenesis and certain tissues of adult mice. A composite enhancer that is active in murine mammary adenocarcinoma cells was previously identified in the first intron of the mts1/S100A4 gene. Here we present a detailed analysis of the structure and function of this enhancer in the Mts1/S100A4-expressing CSML100 and non-expressing CSML0 mouse adenocarcinoma cell lines. In CSML100 cells the enhancer activity is composed of at least six cis-elements interacting with Sp1 and AP-1 family members and CBF/AML/PEBP2 and KRC transcription factors. In addition, a minisatellite-like DNA sequence significantly contributes to the enhancer activity via interaction with abundant proteins, which likely have been described previously under the name minisatellite-binding proteins. Extensive mutational analysis of the mts1/S100A4 enhancer revealed a cooperative function of KRC and the factors binding minisatellite DNA. This is the first example of an enhancer where two nuclear factors earlier implicated in different recombination processes cooperate to activate transcription. In Mts1/S100A4-negative CSML0 cells the strength of the enhancer was 7- to 12.5-fold lower compared to that in CSML100 cells, when referred to the activities of three viral promoters. In CSML0 cells the enhancer could be activated by exogenous AP-1 and CBF transcription factors.


Assuntos
Elementos Facilitadores Genéticos/genética , Genes p16/genética , Íntrons/genética , Repetições Minissatélites/genética , Metástase Neoplásica/genética , Elementos de Resposta/genética , Fatores de Transcrição/metabolismo , Sítio Alostérico , Animais , Sequência de Bases , Proteína de Ligação a CREB , DNA/genética , DNA/metabolismo , Pegada de DNA , Proteínas de Ligação a DNA/metabolismo , Regulação Neoplásica da Expressão Gênica , Genes Virais/genética , Camundongos , Dados de Sequência Molecular , Mutação/genética , Proteínas Nucleares/metabolismo , Especificidade de Órgãos , Regiões Promotoras Genéticas/genética , Fator de Transcrição Sp1/metabolismo , Transativadores/metabolismo , Fator de Transcrição AP-1/metabolismo , Células Tumorais Cultivadas
13.
Genes Chromosomes Cancer ; 32(1): 89-94, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11477665

RESUMO

Approximately 50% of all melanoma families worldwide show linkage to 9p21-22, but only about half of these have been shown to contain germ line CDKN2A mutations. It has been hypothesized that a proportion of these families carry mutations in the noncoding regions of CDKN2A. Several Canadian families have been reported to carry a mutation in the 5' UTR, at position -34 relative to the start site, which gives rise to a novel AUG translation initiation codon that markedly decreases translation from the wild-type AUG (Liu et al., 1999). Haplotype sharing in these Canadian families suggested that this mutation is of British origin. We sequenced 1,327 base pairs (bp) of CDKN2A, making up 1,116 bp of the 5' UTR and promoter, all of exon 1, and 61 bp of intron 1, in at least one melanoma case from 110 Australian families with three or more affected members known not to carry mutations within the p16 coding region. In addition, 431 bp upstream of the start codon was sequenced in an additional 253 affected probands from two-case melanoma families for which the CDKN2A mutation status was unknown. Several known polymorphisms at positions -33, -191, -493, and -735 were detected, in addition to four novel variants at positions 120, -252, -347, and -981 relative to the start codon. One of the probands from a two-case family was found to have the previously reported Q50R mutation. No family member was found to carry the mutation at position -34 or any other disease-associated mutation. For further investigation of noncoding CDKN2A mutations that may affect transcription, allele-specific expression analysis was carried out in 31 of the families with at least three affected members who showed either complete or "indeterminate" 9p haplotype sharing without CDKN2A exonic mutations. Reverse transcription polymerase chain reaction and automated sequencing showed expression of both CDKN2A alleles in all family members tested. The lack of CDKN2A promoter mutations and the absence of transcriptional silencing in the germ line of this cohort of families suggest that mutations in the promoter and 5' UTR play a very limited role in melanoma predisposition.


Assuntos
DNA de Neoplasias/análise , Genes p16/genética , Melanoma/genética , Regiões Promotoras Genéticas/genética , Austrália , Análise Mutacional de DNA/métodos , Éxons/genética , Humanos , Íntrons/genética , Masculino , Polimorfismo Genético/genética
14.
Genes Chromosomes Cancer ; 31(4): 398-401, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11433531

RESUMO

The CDKN2A locus encodes two tumor suppressor proteins, p16(ink4) and p14(arf), through use of alternative first exons. CDKN2A mutations detected in melanoma families are usually missense or nonsense changes which mainly impair p16(ink4) function. Large genomic deletions spanning the entire locus have been observed in two pedigrees with melanomas and nervous tumors. We have detected a novel splice site mutation in a family with melanomas, neurofibromas, and multiple dysplastic nevi. Both alternative mRNAs produced by the mutant allele lacked shared sequences from exon 2, which encodes a substantial portion (>50%) of both p16(ink4) and p14(arf) proteins. The development of neurofibromas can be explained by cooperative effects of combined inactivation of p16(ink4) and p14(arf) or, alternatively, of p14(arf) alone.


Assuntos
Processamento Alternativo/genética , Inibidor p16 de Quinase Dependente de Ciclina/genética , Genes p16/genética , Mutação em Linhagem Germinativa/genética , Melanoma/genética , Neurofibroma/genética , Proteínas/genética , Processamento Pós-Transcricional do RNA/genética , Adolescente , Adulto , Idoso , Feminino , Genes Supressores de Tumor/genética , Humanos , Masculino , Pessoa de Meia-Idade , Linhagem , Proteína Supressora de Tumor p14ARF
15.
Am J Pathol ; 159(1): 205-13, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11438467

RESUMO

Different studies have already shown that the isolated inactivation of p21, p16, or p27 cyclin-dependent kinase inhibitors (CKIs) is associated with increased growth fraction, tumor progression, or decreased overall survival in cases of non-Hodgkin's lymphoma. In this study we linked molecular study of the p53 and p16 genes with immunohistochemical analysis of p27 expression in a group of aggressive B-cell lymphomas [large B-cell lymphomas (LBCLs) and Burkitt's lymphomas]. This was done to analyze the relationship between p53 and p16 silencing, p27 anomalous overexpression, and clinical follow-up, testing the hypothesis that the accumulation of CKI alterations could confer to the tumors a higher aggressivity. In a group of 62 patients, p53 inactivation as a result of mutation was observed in 11 cases (18%) and p16 silencing was seen in 27 cases (43.5%) as a result of methylation (20 of 62), 9p21 deletion (7 of 44), or p16 mutation (2 of 62). The simultaneous inactivation of p53 and p16 was detected exclusively in five LBCL cases. Anomalous expression of p27, which has been proven to be associated with the absence of p27/CDK2 complexes and the formation of p27/cyclin D3 complexes where p27 is inactivated, was detected in 19 of 61 cases (31%). Cases characterized by p27 anomalous expression display concurrent inactivation of p21 (provided by p53 mutations) and/or p16 CKIs in 11 of 14 LBCL cases (P = 0.040). When the relationship between the association of inactivated CKIs and overall survival was considered, a significant relationship was found between a lower overall survival probability and an increased number of inactivated CKIs in LBCL cases, with the worst prognosis for the cases displaying concurrent p53, p16, and p27 alterations. This proves that simultaneous inactivation of different tumor suppressor pathways does indeed take place, and that tumor aggressiveness takes advantage of this CKI-concerted silencing. In this same series of data, Burkitt's lymphoma patients seem to behave in a different way than LBCLs, with p53 and p16 alteration being mutually exclusive and the association with p27 anomalous expression not being clinically significant. These facts seem to support that the additive effect of the inactivation of different CKIs could be dependent of the histological type.


Assuntos
Proteínas de Ciclo Celular/genética , Inativação Gênica , Genes p16/genética , Genes p53/genética , Linfoma de Células B/genética , Linfoma de Células B/fisiopatologia , Proteínas Supressoras de Tumor , Proteínas de Ciclo Celular/metabolismo , Cromossomos Humanos Par 9/genética , Inibidor de Quinase Dependente de Ciclina p27 , Deleção de Genes , Inativação Gênica/fisiologia , Humanos , Linfoma de Células B/mortalidade , Metilação , Mutação , Regiões Promotoras Genéticas/fisiologia , Análise de Sobrevida
16.
An Otorrinolaringol Ibero Am ; 28(3): 303-16, 2001.
Artigo em Espanhol | MEDLINE | ID: mdl-11455887

RESUMO

Five cases of malignant melanomata of the nasal cavities have been diagnosed and studied at ENT--and Anatomopathological Departments, between 1990 and 1997, the group ranging from 65 to 90 years, middle age 74.2. Paramount symptoms were epistaxis and lack of pain in all patients. Radical surgery was performed only in one case, followed by radiotherapy; the remainder were submitted to palliative treatment. We have reviewed the literature and also an immunohistochemical analysis about p53, p16INK4 and Rb oncogenes with the aim to establish its importance in these tumor's type. The whole group have showed high levels of p53 and MIB-1 and 60 percent a loss of oncogen p16 expression.


Assuntos
Expressão Gênica/genética , Genes p16/genética , Genes p53/genética , Melanoma/genética , Melanoma/patologia , Neoplasias Nasais/genética , Neoplasias Nasais/patologia , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Imuno-Histoquímica , Masculino , Melanoma/cirurgia , Neoplasias Nasais/cirurgia , Estudos Retrospectivos
17.
Cancer ; 91(12): 2222-9, 2001 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-11413509

RESUMO

BACKGROUND: Gene-promoter methylation is an epigenetic mechanism of transcription inactivation. In this study, the authors investigated the frequency and prognostic significance of p15 and p16 gene methylation in adult acute leukemia. METHOD: The methylation-specific polymerase chain reaction (MS-PCR) was used to analyze p15 and p16 gene methylation in 49 cases of acute lymphoblastic leukemia (ALL) and 29 cases of acute myelogenous leukemia (AML). RESULTS: At presentation, 93 % of cases of AML (8 of 8 M1, 10 of 11 M2, 2 of 2 M4, 5 of 6 M5, and 2 of 2 M6; French-American-British classification system) showed p15 methylation, but none showed p16 methylation. In ALL, 57% (5 of 8 T-ALL, 16 of 30 common-ALL, 6 of 7 pre-B ALL, and 1 of 4 early B-precursor ALL) showed p15 methylation. Only 6% showed p16 methylation, all of whom had concomitant p15 methylation. One patient acquired p16 methylation during relapse. In 23 ALL karyotyped cases, p15 methylation was found in 6 of 9 cases with normal karyotype, 3 of 7 cases with the Philadelphia chromosome, 3 of 5 cases with complex, 1 with hyperdiploidy, and 1 with trisomy 21. Three more cases with unsuccessful karyotyping but bcr/abl fusion showed p15 methylation as well. Five ALL patients were tested serially for minimal residual disease (MRD) with MS-PCR that has a sensitivity of 10(-4) to 10(-5). All showed continuous positive MS-PCR that heralded hematologic relapse. The prognostic significance of p15 methylation was tested in ALL patients, showing no impact on complete remission, 5-year overall survival, or 5-year disease-free survival. CONCLUSION: Gene methylation of p15, but not p16, is frequent in adult acute leukemias. Methylation of p15 at diagnosis was of no prognostic significance in ALL but may be useful for monitoring MRD.


Assuntos
Proteínas de Ciclo Celular , Genes p16/genética , Leucemia Mieloide Aguda/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Fatores de Transcrição/genética , Proteínas Supressoras de Tumor , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Inibidor de Quinase Dependente de Ciclina p15 , Humanos , Leucemia Mieloide Aguda/mortalidade , Metilação , Pessoa de Meia-Idade , Neoplasia Residual/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/mortalidade , Prognóstico , Sensibilidade e Especificidade , Ativação Transcricional
18.
Cancer ; 91(12): 2294-301, 2001 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-11413518

RESUMO

BACKGROUND: Transcriptional silencing by CpG-island hypermethylation now is believed to be an important mechanism of tumorigenesis. To date, studies on CpG-island hypermethylation in gastric carcinoma and adjacent normal tissues are few. METHODS: The authors examined 5 gastric carcinoma cell lines, 26 frozen gastric carcinoma tissues and their adjacent nontumor area for concurrent CpG-island hypermethylation in 6 tumor-related genes (p15, p16, E-cadherin, GST-pi, hMLH1, and VHL) by methylation-specific polymerase chain reaction. Nontumorous gastric tissues from 10 gastritis patients were used as controls. RESULTS: Hypermethylation was not detected in any tissue taken from gastritis patients but was identified in all 5 cell lines and in 24 (92.3%) gastric carcinoma patients. CpG-island methylation in tumor-related genes also was detected in 7 out of the 25 adjacent normal tissues from cancer patients. Hypermethylation of E-cadherin, p15, and p16 were detected more frequently than GST-pi and hMLH1, whereas aberrant methylation of VHL was not detected. Concurrent hypermethylation in 2 or more tumor-related genes was detected in 3 out of the 5 gastric carcinoma cell lines, 22 (84.6%) tumor samples, and 5 (20%) adjacent gastric tissues. Eighteen (69.2%) tumor samples showed hypermethylation in >or= 3 genes. CONCLUSIONS: The current study showed that concurrent hypermethylation of multiple tumor-related genes is detected frequently in gastric carcinoma and adjacent normal tissues. Study findings suggested that a mechanism that leads to dysregulation in CpG-island methylation is likely to be involved in the early gastric carcinogenesis process.


Assuntos
Caderinas/genética , Carcinoma/genética , Proteínas de Ciclo Celular , Genes p16/genética , Proteínas de Neoplasias/genética , Neoplasias Gástricas/genética , Fatores de Transcrição/genética , Proteínas Supressoras de Tumor , Proteínas Adaptadoras de Transdução de Sinal , Proteínas de Transporte , Inibidor de Quinase Dependente de Ciclina p15 , Humanos , Imuno-Histoquímica , Metilação , Proteína 1 Homóloga a MutL , Proteínas Nucleares , Reação em Cadeia da Polimerase , Células Tumorais Cultivadas
19.
Cancer Lett ; 169(1): 59-68, 2001 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-11410326

RESUMO

Adenoma and dysplasia in the gallbladder (GB) have been reported as precancerous lesions, but the genetic evidence of this is not clearly defined. The purpose of this study was to analyze the frequencies of K-ras, p53, and p16 gene mutations, of microsatellite instability (MI) and of loss of heterozygosity (LOH) in GB cancer, dysplasia, and adenoma. Tissues from 15 GB cancers, five dysplasias around cancerous tumors, and three adenomas were collected prospectively. The mutation rates of K-ras, p53, and p16 were 20.0, 35.7, and 30.7%, respectively, in GB cancers. However, no mutations were found in dysplasia or adenoma. Reduced staining for p16 was seen in 23% of carcinomas. All of the GB carcinomas and four out of five (80%) of the dysplasias showed LOH in a minimum of one locus, but one out of three (33%) cases of adenoma displayed LOH in only one locus. All of the loci of LOH in the dysplasias, except one, showed the same patterns of allelic loss as the adjacent carcinomas. Only one dysplasia showed multiple MI. In conclusion, multiple LOH may be associated with the development of dysplasia and the malignant transformation of GB carcinoma. Gene alterations of K-ras, p53, and p16 are important steps in the malignant changes of dysplasia. However, MI seems to have only a limited role in GB cancer development.


Assuntos
Adenoma/genética , Carcinoma/genética , Neoplasias da Vesícula Biliar/genética , Vesícula Biliar/patologia , Lesões Pré-Cancerosas/genética , Adenoma/metabolismo , Adulto , Idoso , Carcinoma/metabolismo , Inibidor p16 de Quinase Dependente de Ciclina/biossíntese , Inibidor p16 de Quinase Dependente de Ciclina/genética , DNA de Neoplasias/genética , Feminino , Neoplasias da Vesícula Biliar/metabolismo , Genes p16/genética , Genes p53/genética , Genes ras/genética , Humanos , Imuno-Histoquímica , Perda de Heterozigosidade , Masculino , Repetições de Microssatélites/genética , Pessoa de Meia-Idade , Mutação , Lesões Pré-Cancerosas/metabolismo , Proteína Supressora de Tumor p53/biossíntese , Proteína Supressora de Tumor p53/genética
20.
Clin Cancer Res ; 7(6): 1765-72, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11410518

RESUMO

PURPOSE: The objectives of this study were to determine the effects of adenovirus-mediated p16 and p53 on growth and apoptosis in ovarian cancer cells and on survival in nude mice implanted with human ovarian cancer cells. EXPERIMENTAL DESIGN: SKOV-3 ip1 (p53 and p16 null), 2774 (p53 and p16 mutant), and OVCA 420 (p53 and p16 wild-type) cells were used for in vitro studies. SKOV-3 ip1, 2774, and Hey A8 (p53 and p16 wild-type) cells were used in the nude mouse studies. The E1-deleted adenoviruses containing p53, p16, or beta-galactosidase cDNA were transfected into the different cell types or inoculated into the nude mice after injection with ovarian cancer cells. RESULTS: Cell counting, microtetrazolium, and anchorage-independent growth assays on transfected cells demonstrated that p16 and the p16/p53 combination suppressed growth, whereas p53 did not (except in the anchorage-independent growth assay). Although cells infected with the p16/p53 combination had decreased growth compared with cells infected with either tumor suppressor alone, the difference was only statistically significant compared with p53. p16, p53, and the p16/p53 combination all increased apoptosis in the cells. In the nude mice, p16 treatment resulted in the longest survival for all three models, although it only reached statistical significance for the 2774 and SKOV-3 ip1 groups. CONCLUSIONS: Overall, p16 demonstrated greater growth inhibition than p53 both in vivo and in vitro. The p16/p53 combination demonstrated a consistent trend toward increased growth suppression and apoptosis over p16 or p53 alone. Adenovirus-mediated p16 may be a viable future treatment for ovarian cancer.


Assuntos
Adenoviridae/genética , Genes p16/genética , Genes p53/genética , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/terapia , Animais , Apoptose , Western Blotting , Ciclo Celular , Divisão Celular , Sobrevivência Celular , DNA Complementar/metabolismo , Feminino , Humanos , Camundongos , Camundongos Nus , Fatores de Tempo , Transfecção , Células Tumorais Cultivadas , beta-Galactosidase/genética
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