RESUMO
BACKGROUND: Breast cancer patients have a cumulative lifetime risk of 2%-15% of developing a contralateral metastatic or ex novo primary cancer. From prognostic and therapeutic viewpoints, it is important to differentiate metastatic from second primary. To distinguish these entities, we investigated whether the pattern of X chromosome inactivation could determine whether the two tumors derived from different progenitor cells. MATERIALS AND METHODS: The clonality of bilateral breast cancer was evaluated through the X-inactivation analysis using the human androgen receptor gene (HUMARA) polymorphism and the histopathologic and molecular results were compared. A different or an identical pattern of X inactivation was considered as indicator of a second primary cancer or not informative, respectively. We considered morphological indicators of a new primary cancer the absence of concordance in the histological type or a better histological differentiation. RESULTS: Ten patients with bilateral breast cancer were evaluated. Morphological criteria indicated that eight were second primary, a conclusion confirmed by the X-inactivation analysis. Two cases classified as recurrence according to morphological criteria were classified as second tumor by molecular analysis. CONCLUSION: Our results show that the HUMARA clonality assay can improve the histological parameters in differentiating metastatic cancer from second primary cancer.
Assuntos
Neoplasias da Mama/diagnóstico , Neoplasias da Mama/patologia , Carcinoma/diagnóstico , Carcinoma/patologia , Técnicas de Diagnóstico Molecular/métodos , Estadiamento de Neoplasias/métodos , Neoplasias da Mama/genética , Neoplasias da Mama/mortalidade , Carcinoma/genética , Carcinoma/mortalidade , Células Clonais/patologia , Diagnóstico Diferencial , Feminino , Humanos , Antígeno Ki-67/genética , Antígeno Ki-67/metabolismo , Metástase Neoplásica , Neoplasias Primárias Múltiplas/diagnóstico , Neoplasias Primárias Múltiplas/patologia , Reação em Cadeia da Polimerase/métodos , Receptor ErbB-2/genética , Receptor ErbB-2/metabolismo , Receptores de Estrogênio/genética , Receptores de Estrogênio/metabolismo , Receptores de Progesterona/genética , Receptores de Progesterona/metabolismo , Análise de Sobrevida , Estudos de Validação como AssuntoAssuntos
Caspases/genética , Proteínas de Ligação a DNA/metabolismo , Neuroblastoma/enzimologia , Fosfoproteínas/metabolismo , Regiões Promotoras Genéticas , Caspase 8 , Caspases/efeitos dos fármacos , Caspases/metabolismo , Proteínas de Ligação a DNA/efeitos dos fármacos , Regulação Enzimológica da Expressão Gênica , Humanos , Fator Regulador 1 de Interferon , Interferons/farmacologia , Neuroblastoma/genética , Fosfoproteínas/efeitos dos fármacos , Fator de Transcrição STAT1 , Transdução de Sinais/genética , Transativadores/metabolismo , Células Tumorais CultivadasRESUMO
The p73 gene is a p53 homologue localized at 1p36.3, a chromosomal region frequently deleted in neuroblastoma. p73 was originally considered an oncosuppressor gene. However, it was soon realized that its mode of action did not resemble that of a classic anti-oncogene. The recent discovery of N-terminal truncated isoforms, with oncogenic properties, showed that p73 has a 'two in one' structure. Indeed, the full-length variants are strong inducers of apoptosis while the truncated isoforms inhibit the pro-apoptotic activity of p53 and of the full-length p73. This review summarizes some aspects of p73 biology with particular reference to its possible role in neuroblastoma.
Assuntos
Proteínas de Ligação a DNA/fisiologia , Neuroblastoma/metabolismo , Proteínas Nucleares/fisiologia , Processamento Alternativo , Apoptose/fisiologia , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Genes Supressores de Tumor , Humanos , Neuroblastoma/genética , Neuroblastoma/patologia , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Prognóstico , Taxa de Sobrevida , Proteína Tumoral p73 , Proteínas Supressoras de TumorRESUMO
The p73 gene is a p53 homologue which induces apoptosis and inhibits cell proliferation. Although p73 maps at 1p36.3 and is frequently deleted in neuroblastoma (NB), it does not act as a classic oncosuppressor gene. In developing sympathetic neurons of mice, p73 is predominantly expressed as a truncated anti-apoptotic isoform (DeltaNp73), which antagonizes both p53 and the full-length p73 protein (TAp73). This suggests that p73 may be part of a complex tumor-control mechanism. To determine the role of DeltaNp73 in NB we analyzed the pattern of expression of this gene in vivo and evaluated the prognostic significance of its expression. Our results indicate that DeltaNp73 expression is associated with reduced apoptosis in a NB tumor tissue. Expression of this variant in NB patients significantly correlates with age at diagnosis and VMA urinary excretion. Moreover it is strongly associated with reduced survival (HR=7.93; P<0.001) and progression-free survival (HR=5.3; P<0.001) and its role in predicting a poorer outcome is independent from age, primary tumor site, stage and MYCN amplification (OS: HR=5.24, P=0.012; PFS: HR=4.36, P=0.005). In conclusion our data seem to indicate that DeltaNp73 is a crucial gene in neuroblastoma pathogenesis.
Assuntos
Apoptose/fisiologia , Neuroblastoma/diagnóstico , Criança , Pré-Escolar , Proteínas de Ligação a DNA/biossíntese , Proteínas de Ligação a DNA/genética , Genes Supressores de Tumor , Humanos , Lactente , Recém-Nascido , Neuroblastoma/mortalidade , Proteínas Nucleares/biossíntese , Proteínas Nucleares/genética , Prognóstico , Isoformas de Proteínas/biossíntese , Isoformas de Proteínas/genética , Taxa de Sobrevida , Proteína Tumoral p73 , Proteínas Supressoras de TumorAssuntos
Ilhas de CpG/genética , Metilação de DNA , Proteínas de Ligação a DNA/genética , Regulação Neoplásica da Expressão Gênica , Neuroblastoma/genética , Proteínas Nucleares/genética , Animais , Apoptose , Ilhas de CpG/fisiologia , Proteínas de Ligação a DNA/metabolismo , Inativação Gênica , Genes Supressores de Tumor , Humanos , Neuroblastoma/metabolismo , Proteínas Nucleares/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteína Tumoral p73 , Proteínas Supressoras de TumorAssuntos
Neoplasias das Glândulas Suprarrenais/genética , DNA de Neoplasias/genética , Neoplasias Primárias Múltiplas/genética , Neuroblastoma/genética , Neoplasias das Glândulas Suprarrenais/metabolismo , Neoplasias das Glândulas Suprarrenais/patologia , Biomarcadores Tumorais/metabolismo , Criança , Aberrações Cromossômicas , Cromossomos Humanos Par 1/genética , Cromossomos Humanos Par 7/genética , Evolução Fatal , Feminino , Humanos , Antígeno Ki-67/metabolismo , Metástase Linfática , Mutação , Neoplasias Primárias Múltiplas/metabolismo , Neoplasias Primárias Múltiplas/patologia , Neuroblastoma/metabolismo , Neuroblastoma/patologiaRESUMO
p73 is a p53 homolog that, in vitro, inhibits cell growth and induce apoptosis. In some tumors p73 is monoallelically expressed and this raised the possibility that this gene is subjected to imprinting. Silencing of p73 in acute leukemia and in Burkitt's lymphoma occurs in association with the aberrant methylation of the first exon of the gene. We have analysed the methylation pattern of the p73 promoter and of upstream and downstream sequences in neuroblastoma. Our results demonstrate that p73 expression in this tumor is not regulated by methylation. We concluded that it is unlikely that p73 is imprinted in neuroblastoma and that the methylation-dependent silencing of this gene, thus far, is a characteristic of hematologic malignancies. Oncogene (2000) 19, 4553 - 4556.
Assuntos
Metilação de DNA , Proteínas de Ligação a DNA/genética , Genes Supressores de Tumor , Neuroblastoma/genética , Proteínas Nucleares/genética , Sequência de Bases , Ilhas de CpG , Proteínas de Ligação a DNA/metabolismo , Regulação Neoplásica da Expressão Gênica , Inativação Gênica , Células HL-60 , Humanos , Dados de Sequência Molecular , Proteínas Nucleares/metabolismo , Reação em Cadeia da Polimerase/métodos , Regiões Promotoras Genéticas , Proteína Tumoral p73 , Proteínas Supressoras de TumorAssuntos
Proteínas de Ligação a DNA/genética , Proteínas de Neoplasias/genética , Proteínas Nucleares/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Sequência de Aminoácidos , Regulação Leucêmica da Expressão Gênica , Genes Supressores de Tumor , Humanos , Dados de Sequência Molecular , RNA Mensageiro/genética , RNA Neoplásico/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Proteína Tumoral p73 , Proteínas Supressoras de TumorRESUMO
The tp73 gene, a tp53 homologue, has been sub-regionally mapped at 1p36.3, a chromosomal region frequently deleted in neuroblastoma. Due to its chromosomal localization and to the mono-allelic expression observed in some neuroblastoma cell lines, it was proposed that tp73 might be involved in the pathogenesis of neuroblastoma. Functional assays have demonstrated that tp73 can inhibit cell proliferation and induce apoptosis. The role of this gene in tumorigenesis, however, is still unclear. We analyzed tp73 expression in 95 sporadic neuroblastoma samples by RT-PCR and we detected the tp73 transcript in 46 cases (48.4%), without significant correlation with age, clinical stage or 3-year overall survival. A genetic polymorphism in the 2nd exon of tp73 was utilized to identify the transcribed allele in tumor-cell samples. Expression from only one of the tp73 alleles was found in 13 out of 16 heterozygous tumors, while in 3 samples both alleles were present. Genotype analysis of 73 patients and 150 controls showed a significant deviation (p = 0.0308) from the Hardy-Weinberg equilibrium for a tp73 allele only among neuroblastoma patients. The absence of correlation between tp73 expression and clinical stage, age and survival suggests that this gene does not play an essential function in the clinical course of the disease. However, the distribution of genomic tp73 alleles in patients indicates that a role of this gene in the development of neuroblastoma cannot be completely ruled out. Int. J. Cancer (Pred. Oncol.) 84:365-369, 1999.
Assuntos
Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Cromossomos Humanos Par 1 , Regulação Neoplásica da Expressão Gênica , Genes p53 , Neuroblastoma/genética , Neuroblastoma/patologia , Alelos , Neoplasias Encefálicas/mortalidade , Divisão Celular , Deleção Cromossômica , Mapeamento Cromossômico , DNA de Neoplasias/genética , DNA de Neoplasias/isolamento & purificação , Humanos , Estadiamento de Neoplasias , Neuroblastoma/mortalidade , Reação em Cadeia da Polimerase , RNA Neoplásico/genética , RNA Neoplásico/isolamento & purificação , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Taxa de Sobrevida , Transcrição GênicaRESUMO
We report the refined chromosomal localization of the putative tumor suppressor gene TP73 (alias p73) within the genomic region between the anonymous loci D1Z2 and D1S47. The region measures less than 6 Mb and covers a genetic distance of 16 cM. The present mapping considerably restricts the previous cytogenetic localization of TP73.
Assuntos
Neoplasias Encefálicas/genética , Mapeamento Cromossômico , Proteínas de Ligação a DNA/genética , Genes Supressores de Tumor/genética , Neuroblastoma/genética , Proteínas Nucleares/genética , DNA de Neoplasias/análise , Deleção de Genes , Marcadores Genéticos , Humanos , Hibridização in Situ Fluorescente , Células Tumorais Cultivadas , Proteína Tumoral p73 , Proteínas Supressoras de TumorRESUMO
Specific chromosomal aberrations might indicate the position of genes responsible for a particular disease. Neuroblastoma is characterized by frequent deletions and/or rearrangements of the subtelomeric 1p region which, accordingly, is believed to host one or more oncosuppressor gene(s) directly or indirectly involved in the development of this and other tumors. Identification of these genes could be facilitated if cell lines with well characterized interstitial deletions or reciprocal translocations could be available for application of positional cloning strategies. In the present report we present additional and novel molecular data on three well established neuroblastoma cell lines (NLF, NMB and NGP). In one of these we have identified two sites that might be good candidates for hosting oncosuppressor genes; one of these is flanked by the D1S47 and ENO1 loci while the other is distal to the A12M2 locus.
Assuntos
Clonagem Molecular/métodos , Neuroblastoma , Translocação Genética , Humanos , Hibridização in Situ Fluorescente , Células Tumorais Cultivadas/citologia , Células Tumorais Cultivadas/fisiologiaRESUMO
We have analyzed 81 isolates of Mycoplasma agalactiae from four different regions of Italy between 1990 and 1995 in order to identify antigenic differences through SDS-PAGE and Western blotting and chromosomal DNA restriction endonuclease cleavage pattern differences. Antigenic variability in M. agalactiae isolates was investigated analyzing hydrophobic membrane protein fractions by immunoblotting using pooled sheep antiserum from naturally infected sheep. Large restriction fragments obtained cleaving genomic DNAs with SmaI, NruI, SalI, XhoI, BssHII and KpnI were analyzed by pulsed field gel electrophoresis. Genetic analysis indicates that isolates are all similar without intraspecific differences. This homogeneity was confirmed by immunoblotting: 80 and 50 kDa antigens are present in all strains analyzed.
Assuntos
Mycoplasma/genética , Mycoplasma/imunologia , Animais , Variação Antigênica , Antígenos de Bactérias/genética , Antígenos de Bactérias/isolamento & purificação , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Proteínas de Bactérias/isolamento & purificação , Enzimas de Restrição do DNA , DNA Bacteriano/genética , DNA Bacteriano/isolamento & purificação , Eletroforese em Gel de Campo Pulsado , Eletroforese em Gel de Poliacrilamida , Feminino , Immunoblotting , Itália/epidemiologia , Epidemiologia Molecular , Mycoplasma/isolamento & purificação , Infecções por Mycoplasma/epidemiologia , Infecções por Mycoplasma/microbiologia , Infecções por Mycoplasma/veterinária , Ovinos , Doenças dos Ovinos/epidemiologia , Doenças dos Ovinos/microbiologiaRESUMO
Cytogenetic and molecular studies suggest that chromosome 1p might contain oncosuppressor genes involved in the pathogenesis of neuroblastoma and other adult tumors. The isolation of these genes by the 'positional cloning' approach will be facilitated by the characterization of cell lines with well defined chromosomal aberrations. In the present report we provide molecular data on the NGP neuroblastoma cell line which contains a reciprocal t(1;15) translocation. Two regions, possibly hosting oncosuppressor genes, have been identified: one is distal to the ENO1 locus, the other one is comprised between PND and A12M2 and corresponds to that of a constitutional t(1;17) translocation described in a neuroblastoma patient. Genetic data also suggest that the NGP cell line, despite the presence of two chromosomes 1, might be hemizygous for the subtelomeric 1p region.
Assuntos
Cromossomos Humanos Par 15 , Cromossomos Humanos Par 1 , Família Multigênica , Neuroblastoma/genética , Translocação Genética , Adulto , Sequência de Bases , Cromossomos Artificiais de Levedura/genética , DNA de Neoplasias/genética , Rearranjo Gênico , Heterozigoto , Homozigoto , Humanos , Hibridização in Situ Fluorescente , Dados de Sequência Molecular , Sequências Repetitivas de Ácido Nucleico , Células Tumorais CultivadasRESUMO
We report on a Sardinian pedigree with congenital ichthyosis associated with normal levels of steroid sulfatase and a normal molecular pattern, as detectable with a cDNA probe for the steroid sulfatase (STS) gene. Though the pattern of transmission of the disease is consistent with X-linked recessive inheritance, this form of ichthyosis was found to segregate independently of genetic polymorphisms detected by probes of the region Xp22.3, where the STS locus has been mapped. The search for close genetic linkages with other polymorphic markers scattered along the entire X chromosome has so far been fruitless. For the time being, the main conclusion derived from these data is that STS deficiency is not a sine qua non for X-linked ichthyosis which may also result from a mutational event at an X-chromosomal site genetically unlinked to the STS locus.
Assuntos
Arilsulfatases/deficiência , Arilsulfatases/genética , Ictiose Ligada ao Cromossomo X/enzimologia , Ictiose Ligada ao Cromossomo X/genética , Feminino , Ligação Genética , Marcadores Genéticos , Humanos , Ictiose Ligada ao Cromossomo X/patologia , Masculino , Mutação , Linhagem , Fenótipo , Esteril-Sulfatase , Cromossomo X/genéticaRESUMO
A reciprocal t(1;15)(p36.1-36.3;q25-26) has been identified in an established neuroblastoma cell line (NGP) that earlier studies had shown to carry, among others, a rearrangement at the 1p subtelomeric region. Though it has not been possible to establish whether this translocation was constitutional, it is of interest to note that one of the breakpoints is located within the well-known 1p consensus site of tumor-associated chromosomal rearrangements where, as a result of the reciprocal translocation, the FES oncogene has been transferred from autosome 15. It is to be expected that the molecular cloning of the 1p and 15q translocation breakpoints may yield crucial data for understanding the association between specific chromosomal rearrangements and malignant tumor progression.
Assuntos
Cromossomos Humanos Par 15 , Cromossomos Humanos Par 1 , Sequência Consenso , Neuroblastoma/genética , Translocação Genética , Sequência de Bases , Mapeamento Cromossômico , Rearranjo Gênico , Marcadores Genéticos , Humanos , Hibridização in Situ Fluorescente , Dados de Sequência Molecular , Proto-Oncogenes , Células Tumorais CultivadasRESUMO
We have analyzed spontaneous mutations in the adenine phosphoribosyltransferase gene of Chinese hamster clone B cells that exhibit a mutator phenotype because of defective mismatch binding. The mutator phenotype conferred increases in a limited number of mutational classes. The rates of transitions and most transversions were not significantly increased. The rates of A to T transversions and -2 frameshifts were strikingly elevated. These mutations were in repeated elements and 5 of 9 of the frameshifts were dinucleotide deletions in DNA sequences resembling microsatellites. The mismatch binding protein that is defective in the mutator line is a G-T mismatch recognition factor. Band-shift analysis indicated that the preferred substrate for the mismatch recognition protein is duplex DNA containing an extrahelical mono- or dinucleotide within repeated sequences. In agreement with a role in preventing minus frameshifts, a defective binding protein conferred an instability in clone B microsatellite DNA. A mismatch binding defect was also detected in Lo Vo, a human colorectal carcinoma cell line. Extracts of clone B or a second mismatch binding-deficient line, Raji-F12, did not complement Lo Vo extracts, indicating that these lines share a common defect. Our data provide a mechanistic explanation for the relation between defective mismatch recognition and the microsatellite instability of human colon cancer.
Assuntos
Adenina Fosforribosiltransferase/genética , Neoplasias do Colo/genética , Reparo do DNA , Mutagênese , Animais , Sequência de Bases , Células CHO , Cricetinae , Genes , Técnicas In Vitro , Dados de Sequência Molecular , Polimorfismo Genético , Sequências Repetitivas de Ácido Nucleico , Células Tumorais CultivadasRESUMO
Previous reports from our group suggested the preferential integration of the viral construct Ad5/SV40 at the short arm subtelomeric region of human chromosome 1. The present study narrows the region of viral integration to site 1p36.1 in a close cytogenetic overlap with the U1 snRNA gene cluster (RNU1) within a distance necessarily smaller than 400 kb as suggested by the size of the YAC in which the two markers were found to coexist. This finding supports the hypothesis that the chromosomal site in question may have a constitutional propensity to genetic recombination.
Assuntos
Adenovírus Humanos/genética , Cromossomos Humanos Par 1 , RNA Nuclear Pequeno/genética , Vírus 40 dos Símios/genética , Integração Viral , Mapeamento Cromossômico , Cromossomos Artificiais de Levedura , Genes , Humanos , Hibridização in Situ Fluorescente , Mapeamento por RestriçãoRESUMO
The preinsertion site of an adenovirus-5/simian virus 40 recombinant construct (Ad5/SV40) has been cloned and sequenced. Our data suggest that viral integration has occurred in a genomic region which has been the target of multiple events of Alu element retropositions within a TAA minisatellite. Extensive homologies between the left viral end and the host cellular DNA were also observed. The compositional similarity between Adenoviridae and the region of viral integration is consistent with the observed insertion of exogenous DNA in isochores of similar composition [G. Bernardi, Annu. Rev. Genet. 23 (1989) 637-661].
