RESUMEN
OBJECTIVES: The optimal treatment for elderly patients (age >70 years) with glioblastoma (GBM) remains controversial. We conducted a prospective trial in 43 consecutive elderly patients with GBM treated with hypofractionated radiotherapy (RT) followed by adjuvant temozolomide. PATIENTS AND METHODS: Forty-three patients 70 years of age or older with a newly diagnosed GBM and a Karnofsky performance status (KPS) > or = 60 were treated with hypofractionated RT (6 fractions of 5 Gy each for a total of 30 Gy over 2 weeks) followed by up to 12 cycles of adjuvant temozolomide (150-200 mg/m(2) for 5 days during each 28 day cycle). The HRQOL was assessed with the EORTC Quality of Life Questionnaire C30. The primary endpoint was overall survival (OS). Secondary endpoints included progression free survival (PFS), toxicity and quality of life. RESULTS: The median OS was 9.3 months and the median PFS was 6.3 months. The 6 and 12 month survival rates were 86% and 35%, respectively. The 6 and 12 month PFS rates were 55% and 12%, respectively. In multivariate analysis KPS was the only significant independent predictive factor of survival (P = 0.008). Neurological deterioration occurred during or after RT in 16% of patients and was resolved in most cases with the use of steroids. Grade 3-4 hematologic toxicity occurred in 28% of patients during the adjuvant chemotherapy treatment with temozolomide. The treatment had no negative effect on HRQOL, however, fatigue (P = 0.02) and constipation (P = 0.01) scales worsened over time. CONCLUSIONS: Hypofractionated RT followed by temozolomide may provide survival benefit maintaining a good quality of life in elderly patients with GBM. It may represent a reasonable therapeutic approach especially in patients with less favourably prognostic factors.
Asunto(s)
Antineoplásicos Alquilantes/uso terapéutico , Neoplasias Encefálicas/terapia , Dacarbazina/análogos & derivados , Geriatría , Glioblastoma/terapia , Radioterapia/métodos , Anciano , Neoplasias Encefálicas/mortalidad , Neoplasias Encefálicas/psicología , Quimioterapia Adyuvante , Terapia Combinada , Dacarbazina/uso terapéutico , Supervivencia sin Enfermedad , Femenino , Glioblastoma/mortalidad , Glioblastoma/psicología , Humanos , Estado de Ejecución de Karnofsky , Masculino , Estudios Prospectivos , Calidad de Vida , Estudios Retrospectivos , Temozolomida , Resultado del TratamientoRESUMEN
Widespread alteration of the genomic DNA is a hallmark of tumors, and alteration of genes involved in DNA maintenance have been shown to contribute to the tumorigenic process. The DNA polymerase zeta of Saccharomyces cerevisiae is required for error-prone repair following DNA damage and consists of a complex between three proteins, scRev1, scRev3, and scRev7. Here we describe a candidate human homolog of S. cerevisiae Rev7 (hREV7), which was identified in a yeast two-hybrid screen using the human homolog of S. cerevisiae Rev3 (hREV3). The hREV7 gene product displays 23% identity and 53% similarity with scREV7, as well as 23% identity and 54% similarity with the human mitotic checkpoint protein hMAD2. hREV7 is located on human chromosome 1p36 in a region of high loss of heterozygosity in human tumors, although no alterations of hREV3 or hREV7 were found in primary human tumors or human tumor cell lines. The interaction domain between hREV3 and hREV7 was determined and suggests that hREV7 probably functions with hREV3 in the human DNA polymerase zeta complex. In addition, we have identified an interaction between hREV7 and hMAD2 but not hMAD1. While overexpression of hREV7 does not lead to cell cycle arrest, we entertain the possibility that it may act as an adapter between DNA repair and the spindle assembly checkpoint.
Asunto(s)
Proteínas de Unión al Calcio/metabolismo , Proteínas Portadoras/genética , ADN Polimerasa Dirigida por ADN/metabolismo , Proteínas Fúngicas/metabolismo , Proteínas , Proteínas Represoras , Proteínas de Saccharomyces cerevisiae , Secuencia de Aminoácidos , Proteínas Portadoras/química , Ciclo Celular , Proteínas de Ciclo Celular , Clonación Molecular , Daño del ADN , Reparación del ADN , Regulación Neoplásica de la Expresión Génica , Humanos , Proteínas Mad2 , Datos de Secuencia Molecular , Proteínas de Neoplasias/metabolismo , Proteínas Nucleares/metabolismo , Fosfoproteínas/metabolismo , ARN Mensajero/metabolismo , Saccharomyces cerevisiae/metabolismo , Alineación de Secuencia , Células Tumorales CultivadasRESUMEN
MutS homologues have been identified in nearly all organisms examined to date. They play essential roles in maintaining mitotic genetic fidelity and meiotic segregation fidelity. MutS homologues appear to function as a molecular switch that signals genomic manipulation events. Here we describe the identification of the human homologue of the Saccharomyces cerevisiae MSH5, which is known to participate in meiotic segregation fidelity and crossing-over. The human MSH5 (hMSH5) was localized to chromosome 6p22-21 and appears to play a role in meiosis because expression is induced during spermatogenesis between the late primary spermatocytes and the elongated spermatid phase. hMSH5 interacts specifically with hMSH4, confirming the generality of functional heterodimeric interactions in the eukaryotic MutS homologue, which also includes hMSH2-hMSH3 and hMSH2-hMSH6.
Asunto(s)
Proteínas de Unión al ADN , Proteínas Fúngicas/análisis , Proteínas Fúngicas/química , Proteínas de Saccharomyces cerevisiae , Espermatogénesis , Secuencia de Aminoácidos , Secuencia de Bases , Mapeo Cromosómico , Proteínas Fúngicas/genética , Humanos , Masculino , Meiosis , Datos de Secuencia MolecularRESUMEN
Mutations in the ATM gene located on the long arm of chromosome 11 at 11q22-23 cause ataxia-telangiectasia, an autosomal recessive disorder that is associated with increased incidence of malignancy and, particularly, lymphoid tumors. A role for ATM in the development of sporadic T-cell chronic leukemias is supported by the finding of loss of heterozygosity at 11q22-23 and ATM mutations in leukemias carrying TCL-1 rearrangements. Approximately 14% of B-cell chronic lymphocytic leukemia (B-CLL), the most common adult leukemia, carry deletions of the long arm of chromosome 11 at 11q22-23. Loss of heterozygosity at 11q22-23 and, more recently, absence of ATM protein, have been associated with poor prognosis in B-CLL. To determine whether the ATM gene is altered in B-CLL, we have sequenced individual ATM exons in six B-CLL cases. We show that the ATM gene is mutated in a fraction of B-CLLs and that mutations can be present in the germ line of patients, suggesting that ATM heterozygotes may be predisposed to B-CLL.
Asunto(s)
Cromosomas Humanos Par 11 , Leucemia Linfocítica Crónica de Células B/genética , Mutación , Proteínas Serina-Treonina Quinasas , Proteínas/genética , Adulto , Proteínas de la Ataxia Telangiectasia Mutada , Secuencia de Bases , Proteínas de Ciclo Celular , Proteínas de Unión al ADN , Exones/genética , Humanos , Datos de Secuencia Molecular , Análisis de Secuencia de ADN , Proteínas Supresoras de TumorRESUMEN
A search of the Human Genome Sciences database of expressed sequence-tagged DNA fragments, for sequences containing homology to known yeast DNA recombination and repair genes, yielded a cDNA fragment with high homology to RAD54. Here we describe the complete cDNA sequence and the characterization of the genomic locus coding for the human homologue of the yeast RAD54 gene (hRAD54). The yeast RAD54 belongs to the RAD52 epistasis group and appears to be involved in both DNA recombination and repair. The hRAD54 gene maps to chromosome 1p32 in a region of frequent loss of heterozygosity in breast tumors and encodes a protein of M(r) 93,000 that displays 52% identity to the yeast RAD54 protein. The hRAD54 protein sequence additionally contains all seven of the consensus segments of a superfamily of proteins with presumed or proven DNA helicase activity. Mutations in genes with consensus helicase homology have been found in cancer-prone syndromes such as xeroderma pigmentosum and Bloom syndrome as well as Werner's syndrome, in which patients age prematurely, and the X-linked mental retardation with alpha-thalassemia syndrome, ATR-X. We have examined the hRAD54 gene in several breast tumors and breast tumor cell lines and, although the gene region appears to be deleted in several tumors, at present we have found no coding sequence mutations.
Asunto(s)
Neoplasias de la Mama/genética , Deleción Cromosómica , Cromosomas Humanos Par 1/genética , Proteínas Fúngicas/genética , Proteínas de Saccharomyces cerevisiae , Secuencia de Aminoácidos , Secuencia de Bases , Northern Blotting , Mapeo Cromosómico , ADN Helicasas , Enzimas Reparadoras del ADN , Exones , Heterocigoto , Humanos , Intrones , Datos de Secuencia Molecular , Polimorfismo Conformacional Retorcido-Simple , Distribución Tisular , Células Tumorales CultivadasRESUMEN
Heterozygosity for ataxia-telangiectasia (A-T), a cancer-prone recessive syndrome, has been associated with an increased risk of breast cancer. The gene for A-T (ATM) is located at chromosomal region 11q22-q23, a region of frequent loss of constitutional heterozygosity in breast and other tumors. Loss of constitutional heterozygosity at 1lq22-q23 was found in 47% of informative cases in the series of primary tumors analyzed in this study. To investigate the role of ATM in breast cancer, we have determined the complete genomic organization of the gene, developed an exon-scanning PCR single-strand conformation polymorphism (PCR-SSCP) assay for mutation detection of ATM, and screened 38 consecutive breast tumors for mutations using both genomic DNA- and cDNA-based assays. In addition to common ATM polymorphisms detected both in the coding sequence and in flanking introns, seven unique SSCP alleles were identified in six tumor DNAs. Sequence analysis of these alleles revealed rive nucleotide substitutions that were predicted to change the encoded amino acid. However, PCR-SSCP and nucleotide sequencing analysis of the paired blood samples and of an extended sample size of a total of 224 chromosomes indicated that these SSCP patterns represent constitutional rare polymorphisms with a frequency between 0.005 and 0.023. Because the majority of A-T mutations are null mutations and none of the ATM alleles found in breast cancer samples would lead to the truncation of the translation product, we conclude that, in this initial sample of sporadic breast cancer patients, there was no evidence for an increased number of A-T carriers. In addition, because no somatic mutations were found, our study rules out the ATM gene as the frequently altered tumor suppressor gene at 11q23.
Asunto(s)
Ataxia Telangiectasia/genética , Neoplasias de la Mama/genética , Cromosomas Humanos Par 11/genética , Eliminación de Gen , Genes Supresores de Tumor/genética , Secuencia de Bases , Análisis Mutacional de ADN , Susceptibilidad a Enfermedades , Femenino , Humanos , Persona de Mediana Edad , Datos de Secuencia Molecular , Reacción en Cadena de la PolimerasaRESUMEN
The ALL1 gene is found rearranged in approximately 10% of acute lymphoblastic leukemias and in over 5% of acute myeloid leukemias. The gene undergoes fusion with either a variety of partner genes located on different chromosomes or with itself. To further characterize the role of the ALL1 gene in the leukemogenic process, and possibly in solid malignancies, we defined its complete genomic structure. The gene, which spans a region on chromosome band 11q23 approximately 90 kb in length, consists of 36 exons, ranging in size from 65 bp to 4249 bp. The determination of intronic sequences flanking the exon boundaries will allow the determination of whether point mutations may be responsible for inactivation of the gene in solid tumors showing loss of heterozygosity at region 11q23.
Asunto(s)
Proteínas de Unión al ADN/genética , Exones , Leucemia Mieloide/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Proto-Oncogenes , Factores de Transcripción , Secuencia de Bases , Mapeo Cromosómico , Cromosomas Humanos Par 11 , Cartilla de ADN , ADN Complementario , Reordenamiento Génico , N-Metiltransferasa de Histona-Lisina , Humanos , Datos de Secuencia Molecular , Proteína de la Leucemia Mieloide-Linfoide , Mapeo Restrictivo , Dedos de ZincRESUMEN
The ATM gene, involved in the genetic disorder ataxia-telangiectasia (AT), has been identified recently. This gene is suspected to predispose to malignancy and is located in a chromosomal region that we have recently found deleted in 50 to 60% of breast and lung carcinomas. Because of its location and its function, the ATM gene is a strong candidate tumor suppressor or modifier gene of chromosome region 11q23. In this study, we define its genomic structure. The aim was to establish the basis for the development of mutation scanning methods based on DNA instead of RNA. We found that the gene spans a region of approximately 70-80 kb and is composed of 37 exons, ranging in size from 64 to 324 bp. Nucleotide sequences of all exon/intron boundaries were determined. With this information, it will be possible to develop simple genetic tests for the identification of homozygotes and heterozygotes, as well as determine whether the gene is involved in the pathogenesis of breast and other carcinomas.
Asunto(s)
Ataxia Telangiectasia/genética , Genes Supresores de Tumor , Proteínas Serina-Treonina Quinasas , Proteínas/genética , Proteínas de la Ataxia Telangiectasia Mutada , Secuencia de Bases , Proteínas de Ciclo Celular , Cromosomas Humanos Par 11 , Cartilla de ADN/química , ADN Complementario/genética , Proteínas de Unión al ADN , Exones , Humanos , Intrones , Datos de Secuencia Molecular , Proteínas Supresoras de TumorRESUMEN
We examined the pattern of allelic loss in 76 adenocarcinomas of the lung using 14 highly informative microsatellite markers on the long arm of chromosome 11. Loss of heterozygosity was found in 48 of 76 tumors (63%). Three distinct regions of deletion were identified. The first region, the most centromeric, lies between markers D11S940 and CD3D: the second, delimited by markers D11S924 and D11S925, is estimated to be 4 Mb in length, and has never been previously described; a third, more telomeric region, the length of which is also estimated to be in the range of 4 Mb, is bracketed by loci D11S1345 and D11S1328. These findings suggest the presence of at least three tumor suppressor genes on the long arm of chromosome 11, and confirm the relevance of 11q22-24, a region frequently deleted in carcinomas of the breast, ovary, uterine, cervix, colon, and malignant melanoma in the pathogenesis of solid tumors. The characterization of minimal regions of loss could provide the basis for the identification and cloning of the critical genes.
Asunto(s)
Adenocarcinoma/genética , Deleción Cromosómica , Cromosomas Humanos Par 11 , Neoplasias Pulmonares/genética , Adulto , Anciano , Humanos , Persona de Mediana EdadRESUMEN
Chromosome 11 is frequently altered in several types of human neoplasms. In breast cancer, loss of heterozygosity has been described in two regions of this chromosome, 11p15 and 11q22-23. In this report we have dissected the two regions using high-density polymorphic markers, and have found that there are at least two independent areas of loss of heterozygosity in each region, suggesting that multiple genes on chromosome 11 may be targets of genetic alteration during tumor establishment or progression. The regions defined are: at 11p15, between loci D11S576 and D11S1318 and between D11S988 and D11S1318; at 11q23, between D11S2000 and D11S897 and between D11S528 and D11S990. The narrowing of these regions of loss should facilitate the cloning of the regions in yeast artificial chromosomes to identify the critical tumor suppressor genes.
Asunto(s)
Neoplasias de la Mama/genética , Mapeo Cromosómico , Cromosomas Humanos Par 11 , Eliminación de Gen , Secuencia de Bases , Neoplasias de la Mama/patología , Clonación Molecular , Genes Supresores de Tumor , Marcadores Genéticos , Heterocigoto , Humanos , Metástasis Linfática , Índice Mitótico , Datos de Secuencia Molecular , Estadificación de NeoplasiasRESUMEN
Evidence from cytogenetics, multipoint linkage analyses of familial melanoma, and loss of heterozygosity studies of familial and sporadic melanomas support localization of a melanoma susceptibility or tumor suppressor gene at chromosomal region 9p21-23. Recently, the inhibitor of cyclin-dependent kinase 4 (CDK4I; also known as p16INK4, multiple tumor suppressor 1, or CDKN2 gene) has been mapped to 9p21 and shown to be mutated or deleted in a large fraction of cell lines derived from many tumor types, including melanoma, suggesting that this gene could be a melanoma suppressor gene. In order to test for somatic mutations in the CDK4I gene in tumors, DNAs from 30 surgically resected melanomas of both cutaneous and uveal origins were sequenced. No mutations were detected in the coding region of the CDK4I gene, while mutations or deletions were detected in 60% (9 of 15) of the cultured melanoma cell line DNAs. Among presumptive familial cases, nine of which were members of families with one or two other documented melanoma cases, no germline mutations were detected by sequence analysis. A deletion in the second exon of the CDK4I gene was found in one germline allele of a familial melanoma patient from a family with eight affected first degree relatives. These results not only support the suggestion that the CDK4I gene is a familial malignant melanoma gene, they also suggest the presence of another suppressor gene locus within 9p21 which is the target of loss of heterozygosity in sporadic melanomas.