Search PubMed⌕ Search

Biomedical subjects

B Vogelstein

Publications and source records attributed to B Vogelstein.

At least 253 records · Page 14Linked to original sources
PubMed1989

Systemic immunity against a murine colon tumor (CT-26) produced by immunization with syngeneic cells expressing a transfected viral gene product.

We have previously shown that CT-26 tumor cells expressing the transfected hemagglutination antigen of influenza virus elicit an immune response in syngeneic hosts that is cross-protective against an s.c. challenge with non-transfected parental cells. Since CT-26 is a murine colorectal carcinoma we sought to determine whether the same immuno-protective effect could be achieved after a challenge with parent tumor cells injected into the usual sites of colon tumor growth and metastasis. We now show that the protection afforded by this immunization protocol is systemic and that animals can be protected against tumor growth in the cecum, lymphatics of the mesentery, liver and lung.

Adenocarcinoma↗
PubMed1989

Allelotype of colorectal carcinomas.

To examine the extent and variation of allelic loss in a common adult tumor, polymorphic DNA markers were studied from every nonacrocentric autosomal arm in 56 paired colorectal carcinoma and adjacent normal colonic mucosa specimens. This analysis was termed an allelotype, in analogy with a karyotype. Three major conclusions were drawn from this analysis: (i) Allelic deletions were remarkably common; one of the alleles of each polymorphic marker tested was lost in at least some tumors, and some tumors lost more than half of their parental alleles. (ii) In addition to allelic deletions, new DNA fragments not present in normal tissue were identified in five carcinomas; these new fragments contained repeated sequences of the variable number of tandem repeat type. (iii) Patients with more than the median percentage of allelic deletions had a considerably worse prognosis than did the other patients, although the size and stage of the primary tumors were very similar in the two groups. In addition to its implications concerning the genetic events underlying tumorigenesis, tumor allelotype may provide a molecular tool for improved estimation of prognosis in patients with colorectal cancer.

Alleles↗
PubMed1989

Chromosome 17 deletions and p53 gene mutations in colorectal carcinomas.

Previous studies have demonstrated that allelic deletions of the short arm of chromosome 17 occur in over 75% of colorectal carcinomas. Twenty chromosome 17p markers were used to localize the common region of deletion in these tumors to a region contained within bands 17p12 to 17p13.3. This region contains the gene for the transformation-associated protein p53. Southern and Northern blot hybridization experiments provided no evidence for gross alterations of the p53 gene or surrounding sequences. As a more rigorous test of the possibility that p53 was a target of the deletions, the p53 coding regions from two tumors were analyzed; these two tumors, like most colorectal carcinomas, had allelic deletions of chromosome 17p and expressed considerable amounts of p53 messenger RNA from the remaining allele. The remaining p53 allele was mutated in both tumors, with an alanine substituted for valine at codon 143 of one tumor and a histidine substituted for arginine at codon 175 of the second tumor. Both mutations occurred in a highly conserved region of the p53 gene that was previously found to be mutated in murine p53 oncogenes. The data suggest that p53 gene mutations may be involved in colorectal neoplasia, perhaps through inactivation of a tumor suppressor function of the wild-type p53 gene.

Alleles↗
PubMed1989

In situ hybridization localizes the human putative oncogene GLI to chromosome subbands 12q13.3-14.1.

Using in situ hybridization, we have localized the human putative oncogene GLI to chromosome subbands 12q13.3-14.1. The precise genomic site is of interest since the region 12q13-15 has been found to be consistently rearranged in neoplasia-associated chromosome abnormalities in lipomas, myxoid liposarcomas, uterine leiomyomas, and pleomorphic adenomas of the salivary gland.

Chromosome Banding↗
PubMed1988

Genetic alterations during colorectal-tumor development.

Because most colorectal carcinomas appear to arise from adenomas, studies of different stages of colorectal neoplasia may shed light on the genetic alterations involved in tumor progression. We looked for four genetic alterations (ras-gene mutations and allelic deletions of chromosomes 5, 17, and 18) in 172 colorectal-tumor specimens representing various stages of neoplastic development. The specimens consisted of 40 predominantly early-stage adenomas from 7 patients with familial adenomatous polyposis, 40 adenomas (19 without associated foci of carcinoma and 21 with such foci) from 33 patients without familial polyposis, and 92 carcinomas resected from 89 patients. We found that ras-gene mutations occurred in 58 percent of adenomas larger than 1 cm and in 47 percent of carcinomas. However, ras mutations were found in only 9 percent of adenomas under 1 cm in size. Sequences on chromosome 5 that are linked to the gene for familial adenomatous polyposis were not lost in adenomas from the patients with polyposis but were lost in 29 to 35 percent of adenomas and carcinomas, respectively, from other patients. A specific region of chromosome 18 was deleted frequently in carcinomas (73 percent) and in advanced adenomas (47 percent) but only occasionally in earlier-stage adenomas (11 to 13 percent). Chromosome 17p sequences were usually lost only in carcinomas (75 percent). The four molecular alterations accumulated in a fashion that paralleled the clinical progression of tumors. These results are consistent with a model of colorectal tumorigenesis in which the steps required for the development of cancer often involve the mutational activation of an oncogene coupled with the loss of several genes that normally suppress tumorigenesis.

Adenoma↗
PubMed1988

Induction in a murine tumor of immunogenic tumor variants by transfection with a foreign gene.

Transfection of the undifferentiated murine colon carcinoma line CT-26 with the gene coding for the hemagglutination antigen (HA) of influenza virus resulted in the generation of highly immunogenic tumor cells. CT-26 cells transfected with HA not only failed to grow in syngeneic mice but also protected normal animals against a challenge with otherwise lethal doses of parental nontransfected cells. The immunogenicity of HA-transfected cells appeared to correlate with surface HA expression in that tumorigenic clones of HA-transfected CT-26 cells expressed little HA, while immunogenic clones were high expressers of HA. Irradiation of immunogenic HA clones did not abrogate their immunogenicity. These observations demonstrate that immune recognition of a poorly immunogenic tumor can be produced by immunization with tumor cells expressing a defined, foreign cell surface antigen.

Animals↗
PubMed1988

Amplification and expression of the epidermal growth factor receptor gene in human glioma xenografts.

Xenografts from eight malignant human gliomas were established in athymic mice and were used to study amplification and expression of the epidermal growth factor receptor (EGFR) gene. Tissue identity between biopsy and xenografts was confirmed by karyotypic profiles, which showed that each glioma xenograft retained structural abnormalities, including double minute chromosomes, present in the parent glioma. EGFR gene amplification was found in six of the eight glioma biopsies and their corresponding xenografts. Expression of the EGFR gene was measured by Scatchard analysis, affinity reactions, immunoprecipitations, Western immunoblots, and immunocytochemistry; significant expression of the EGFR gene was only detectable in xenografts with EGFR gene amplification. Moreover, five of the six xenografts with EGFR gene amplification demonstrated structural alterations of the EGFR gene, which was associated with low-molecular-weight EGFR proteins. These xenografts represent an excellent tissue source and in vivo model system for characterizing the epidermal growth factor receptor in malignant human gliomas.

Animals↗
PubMed1988

The GLI gene is a member of the Kruppel family of zinc finger proteins.

Many studies have established that a select subset of normal cellular genes are altered in cancer by point mutations, translocations or gene amplification. However, the vast majority of genetic changes that occur in neoplastic cells have not yet been identified. In an attempt to identify some of these other genetic changes, we have recently isolated a gene, GLI, by virtue of its amplification in a human glioblastoma. Subsequently, GLI was found to be amplified in other human glioblastomas (ref. 3 and unpublished data). To understand better the role of GLI in human neoplasia, we have now cloned the GLI complementary DNA (cDNA) and determined its nucleotide sequence. Analysis of the predicted translation product reveals that it contains five repeats of a DNA binding consensus sequence (zinc finger) originally described in Xenopus Transcription Factor III A (TFIIIA). Furthermore, these zinc fingers contain sequence elements that suggest the GLI gene product is a member of the recently described Kruppel family of zinc finger proteins. Additional experiments demonstrate that GLI is an evolutionarily conserved gene that is expressed in embryonal carcinoma cells but not in most adult tissues. The link between the developmentally important Kruppel family of genes and GLI is interesting considering the similarities between developing embryonic and neoplastic tissue.

Amino Acid Sequence↗
PubMed1988

Gene amplification in malignant human gliomas: clinical and histopathologic aspects.

Gene amplification occurs in 45-50% of malignant human gliomas (MHG). In the present study, 64 genetically characterized gliomas were evaluated to determine if tumors with amplification of the epidermal growth factor receptor (EGFR), N-myc, c-myc, or gli genes had distinctive histopathologic features. There was no significant difference in age (p = 0.10) or gender (p = 0.78) between patients whose tumors contained amplified genes and those whose tumors did not exhibit this characteristic. Although the patients with amplified genes in their tumors survived slightly longer than patients whose tumors had no detectable gene amplification, these differences were not statistically significant (p = 0.21). The 28 tumors with amplification included 24/48 (50%) glioblastoma multiforme, 2/6 (33%) anaplastic astrocytomas and 2/5 (40%) gliosarcomas. No amplification was seen in one oligodendroglioma, three anaplastic mixed gliomas or one giant cell glioblastoma multiforme. Necrosis and endothelial proliferation were equally prevalent among tumors with and without amplification. Comparison of tumors with gene amplification and tumors without this characteristic revealed similar distributions of most morphologic cells types. Although prominent perivascular lymphocytic infiltrates were more frequent in tumors without amplification, this association was of borderline significance statistically. In situ hybridization of tumors with amplification using an EGFR mRNA probe showed intense labeling of different neoplastic cell types including fibrillary and protoplasmic astrocytes, gemistocytes, anaplastic cells, and multinucleated giant cells. Non-neoplastic cells such as hyperplastic endothelium within the tumors did not express detectable EGFR mRNA. These studies demonstrate that (a) cells with quite different morphology within the same tumor can contain the same genetic alteration; (b) tumors of identical histological appearance may have arisen and evolved by different molecular mechanisms; and (c) molecular analyses are necessary to evaluate gene amplification in MHG since this characteristic cannot be accurately predicted by the morphologic or clinical criteria used in this study.

Adult↗
PubMed1988

Characterization of N-myc amplification units in human neuroblastoma cells.

A set of DNA clones comprising 48 independent HindIII fragments (215 kilobases of sequence) was derived from the N-myc amplification unit of the neuroblastoma cell line NGP. These clones were used to investigate N-myc amplification units in NGP cells and 12 primary neuroblastoma tumors. Three parameters were evaluated: (i) the number of rearrangements from germ line configuration that had occurred during the amplification process; (ii) the homogeneity of amplification units within individual tumors; and (iii) the conservation of amplified sequences among different tumors. The results indicated that remarkably few rearrangements had occurred during amplification, that the amplification units within any one tumor were quite homogeneous, and that although each tumor contained a unique pattern of amplified DNA fragments, there was considerable similarity between the amplification units of different tumors. In particular, the amplification units were strikingly similar over a contiguous domain of at least 140 kilobases surrounding the N-myc structural gene.

Cell Line↗
PubMed1988

The GLI-Kruppel family of human genes.

Previous characterization of GLI, a gene found to be amplified and expressed in a subset of human brain tumors, revealed the presence of five tandem zinc fingers related to those of Krüppel (Kr), a Drosophila segmentation gene of the gap class. We have used the GLI cDNA as a molecular probe to isolate related sequences from the human genome. Partial characterization of six related loci, including sequence determination, expression studies, and chromosome localization, revealed that each locus could encode a separate finger protein. The predicted proteins all had similar H-C links, i.e., a conserved stretch of 9 amino acids connecting the C-terminal histidine of one finger to the N-terminal cysteine of the next. On the basis of amino acid sequence and intron-exon organization, the genes could be placed into one of two subgroups: the GLI subgroup (with the consensus finger amino acid sequence [Y/F]XCX3GCX3[F/Y]X5LX2HX3-4H[T/S]GEKP) or the Kr subgroup (with the consensus finger amino acid sequence [Y/F]XCX2CX3FX5LX2HXRXHTGEKP). Unlike GLI or Kr, most of the newly isolated genes were expressed in many adult tissues. The predicted proteins probably control the expression of other genes and, by analogy with Kr and GLI, may be important in human development, tissue-specific differentiation, or neoplasia.

Amino Acid Sequence↗
PubMed1988

Carrier detection in the Wiskott Aldrich syndrome.

The Wiskott-Aldrich syndrome (WAS) is an X-linked recessive disease characterized by immunodeficiency and severe thrombocytopenia in affected males, but no demonstrable clinical abnormalities in carrier females. Through analysis of the methylation patterns of X-linked genes that display restriction fragment length polymorphisms (RFLPs), we studied the pattern of X-chromosome inactivation in various cell populations from female relatives of patients with WAS. The peripheral blood T cells, granulocytes, and B cells of eight obligate WAS carriers were found to display specific patterns of X-chromosome inactivation clearly different from these of normal controls. Thus, carriers of WAS could be accurately identified using this analysis.

B-Lymphocytes↗
PubMed1987

Clonal analysis of human colorectal tumors.

The clonal composition of human colorectal tumors was studied by means of restriction fragment length polymorphisms (RFLPs). First, X-linked RFLPs were used to examine the pattern of X chromosome inactivation in colorectal tumors of females. All 50 tumors examined showed monoclonal patterns of X chromosome inactivation; these tumors included 20 carcinomas as well as 30 adenomas of either familial or spontaneous type. Second, RFLPs of autosomes were used as clonal markers to detect the somatic loss or gain of specific chromosomal sequences in colorectal tumors. Among other changes, it was found that somatic loss of chromosome 17p sequences occurred in over 75 percent of the carcinomas examined, but such loss was rare in adenomas. These data support a monoclonal origin for colorectal neoplasms, and suggest that a gene on the short arm of chromosome 17 may be associated with progression from the benign to the malignant state.

Adenoma↗
PubMed1987

Clonal analysis using recombinant DNA probes from the X-chromosome.

It has been demonstrated that restriction fragment length polymorphisms of X-chromosome genes can be used in conjunction with methylation patterns to determine the clonal composition of human tumors. In this report, we show that several X-chromosome probes can be used for such analyses. In particular, probes derived from the hypoxanthine phosphoribosyltransferase gene and the phosphoglycerate kinase gene could be used for clonal analysis in over 50% of American females. The X-inactivation patterns observed with these probes were found to accurately reflect clonality in more than 95% of 92 tumors tested.

Alleles↗
PubMed1987

Identification of an amplified, highly expressed gene in a human glioma.

A gene, termed gli, was identified that is amplified more than 50-fold in a malignant glioma. The gene is expressed at high levels in the original tumor and its derived cell line and is located at chromosome 12 position (q13 to q14.3). The gli gene is a member of a select group of cellular genes that are genetically altered in primary human tumors.

Cell Line↗
PubMed1987

Carrier detection in X-linked agammaglobulinemia by analysis of X-chromosome inactivation.

We used a recently developed strategy to analyze patterns of X-chromosome inactivation in human cell populations in order to study female members of families with X-linked agammaglobulinemia--i.e., to detect the carrier state and to test the hypothesis that the disorder results from a defect intrinsic in the development of B cells. According to this strategy, recombinant-DNA probes simultaneously detect restriction-fragment-length polymorphisms and patterns of methylation of X-chromosome genes. Random X-inactivation patterns were observed in isolated peripheral-blood granulocytes, T lymphocytes, and B lymphocytes of women who were not carriers. In contrast, one of the two X chromosomes was preferentially active in the peripheral B cells, but not the T cells or granulocytes, of three carriers of the disorder. This observation strongly supports the hypothesis that X-linked agammaglobulinemia results from an intrinsic defect in B-cell development. Moreover, the analysis described here can be used for direct identification of carriers in families with this disease.

Agammaglobulinemia↗
PubMed1987

Alterations in DNA methylation in human colon neoplasia.

A review of studies on DNA methylation in colonic neoplasia is presented. Hypomethylation of a wide variety of genes from throughout the genome was seen in all colon cancers studied. These changes preceded malignancy because benign adenomas were also affected.

Adenocarcinoma↗