Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Eleven pediatric brain tumors were studied for the histone H3, Vimentin and MYC gene expression. H3, an S phase cell cycle-related gene (ccr), was found prevalently expressed in tumors with a high mitotic index (MI). Vimentin gene, which contributes to maintaining the cell structure but is also demonstrated to be an early responder gene to growth stimulation was found variously expressed. The different expression of Vimentin gene in the examined samples suggests the active proliferation of the tumor cells. Analysis of MYC gene expression was found increased only in a mesenchymal chondrosarcoma while in other samples MYC mRNA was undetectable. Medulloblastoma, chondrosarcoma, and choroid plexus carcinoma have high S phase H3 gene expression associated with a high MI. Differently an astrocytoma shows a low MI associated with high H3 gene expression. This first preliminary report of H3, Vimentin and MYC gene expression in brain tumors demonstrates that malignant cells are characterized by a different gene expression and different growth potentials.
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PMID:Expression of histone H3 cell cycle-related gene, vimentin and MYC genes in pediatric brain tumors. A preliminary analysis showing the different malignant cell growth potential. 131

A missense mutation at cysteine 706, resulting in a retinoblastoma (RB) protein defective in phosphorylation and oncoprotein binding, has been isolated from a human tumor cell line. Since this residue is conserved in murine RB and in the related p107 protein, we studied the activity of in vitro mutants flanking this position. These experiments demonstrated that the thiol atom at codon 706 does not possess intrinsic functional activity as small polar or nonpolar residues could substitute at either codons 706 or 707, while bulkier R-group changes in these positions interfered with in vitro oncoprotein binding or in vivo protein phosphorylation. A series of missense mutants in an adjacent leucine repeat domain also demonstrated a loss of oncoprotein binding that was proportional to the magnitude of amino acid substitutions. To determine whether the cysteine 706 --> phenylalanine RB mutant retained any protein binding activity, we examined its ability to precipitate MYC, which was recently identified as a potential RB-associated protein. These experiments demonstrated that the mutant RB product is capable of binding in vitro to c-myc and L-myc proteins with comparable affinity as wild-type RB. These findings raise questions about the functional role of the RB:MYC interactions and emphasize important differences in the binding patterns between MYC and the other RB-associated proteins.
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PMID:Functional analysis at the Cys706 residue of the retinoblastoma protein. 133 91

An unambiguous and rapid characterization of amplified DNA sequences in tumor cells is important for the understanding of neoplastic progression. This study was conducted to evaluate the potential of fluorescence in situ hybridization (FISH) to identify such amplified DNA sequences in human tumor cell lines. Applying this technique, we followed the metaphase location and interphase position of amplified DNA sequences corresponding to the SAMK, MYC, and MYCN genes in four cell lines derived from human tumors: two gastric carcinoma lines (KATO III and SNU-16), a neuroblastoma (NUB-7), and a neuroepithelioma (NUB-20) line. In metaphase cells of KATO III, NUB-7, and NUB-20 lines, the amplified regions were clearly visible and easily identified at an intrachromosomal location: in KATO III and NUB-7 at a terminal position and in NUB-20 at an interstitial position. In SNU-16, on the other hand, the amplified SAMK and MYC sequences were identified in extrachromosomal double minute chromosomes (DMs). In this line, the SAMK and MYC sequences were coamplified in the same cells and were colocated on the same DMs. FISH also allowed the identification of amplified DNA sequences in nondividing cells, enabling us to distinguish, at interphase, whether the amplification gave rise to intrachromosomal amplified regions (IARs) or to extrachromosomal DMs. The FISH technique also allowed us to determine at metaphase as well as at interphase the extent of amplification and the size of the IARs.
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PMID:Detection of amplified DNA sequences in human tumor cell lines by fluorescence in situ hybridization. 137 38

A 6-year-old girl presented with a tumor of the right shoulder involving bone, adjacent soft tissue, and regional lymph nodes. The conventional histologic diagnosis was ambiguous, initially suggesting lymphoma. After relapse on lymphoma therapy, reevaluation with additional multiple diagnostic techniques performed on the biopsy tissue and on two cell lines derived from the biopsies established the diagnosis of a primitive neuroepithelial tumor of bone and soft tissue. This was strongly supported by 1) focal rosette formation by the tumor cells and positive immunostaining for neuron-specific enolase and synaptophysin, with absent staining for leukocyte common antigen; 2) at the ultrastructural level, formation of cellular processes containing microtubules, a paucity of neurosecretory granules, absence of synaptic junctions, formation of long "intermediate" junctions between cells, and, in culture, widespread development of rosettes; 3) marked surface positivity to W 6/32 and negativity to HSAN 1.2 antibodies; and 4) elevated expression of MYC and lack of overexpression of MYCN oncogenes. Numerical and structural abnormalities were present in the karyotype, but the expected t(11;22)(q24;q12) was not present in the tumor-involved marrow or in either of the established tumor cell lines, although there was an interstitial deletion of 11q involving breakpoints in q21 and q23.
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PMID:Two malignant peripheral primitive neuroepithelial tumor cell lines established from consecutive samples of one patient: characterization and cytogenetic analysis. 138 59

The genetic basis for the development of multiple myeloma (MM) remains poorly understood, in part because MM has thus far been relatively refractory to cytogenetic analysis. The few cases karyotyped have pointed to involvement of 11q13, site of the BCL1 proto-oncogene, or of 8q24, site of the MYC proto-oncogene. A recent molecular study detected rearrangements distal to the MYC gene in 16% of MM, using the MLVI-4 probe. The immunocytochemical demonstration of BCL2 protein overexpression in at least some cases of MM has suggested the possibility of translocation-mediated deregulation of the BCL2 proto-oncogene. The configuration of the BCL2 gene in MM, however, has not yet been defined using all available breakpoint probes. To address these issues, we studied 17 patients with plasma cell dyscrasias (16 MM, 1 plasmacytoma) by Southern blotting using the major breakpoint region (MBR), minor cluster region (MCR), and 5' cDNA (pB16) BCL2 breakpoint probes; with the BCL1 major translocation cluster (MTC) breakpoint probe; and with a probe to the MYC-associated MLVI-4 region (PA1.3SB). In all 17 cases, rearrangement of one or both alleles of the immunoglobulin heavy chain gene had been demonstrated, thereby confirming the presence of tumor DNA in the samples studied. None of the cases tested showed a rearrangement with the MBR BCL2 (0/16), MCR BCL2 (0/17), 5' cDNA BCL2 (0/16), BCL1 MTC (0/15), or MLVI-4 (0/15) probes. These results suggest that if BCL2 deregulation does indeed occur in MM, a mechanism other than translocation must be involved in most cases. Furthermore, rearrangements distal to the MYC gene, in the region of the MLVI-4 probe, may be less common than previously thought. Finally, a significant proportion of translocation breakpoints in band 11q13 may not be detected by the BCL1 MTC probe in MM, as is true in lymphomas.
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PMID:Proto-oncogene analysis in multiple myeloma. 141 86

Deregulation of the proto-oncogene MYC by specific chromosomal translocations has been shown to be essential but not sufficient for the development of Burkitt's lymphoma (BL). To identify other genes which either mark important steps in tumorigenesis or which reflect the cellular differentiation state of BL cells we have compared tumor cells to immortalized lymphoblastoid B cells by subtractive hybridization. We have identified a complementary DNA clone which encodes a novel member of the superfamily of GTP-binding (G) protein-coupled receptors, designated BLR1. The corresponding mRNA is expressed in BL and lymphatic tissues but not in other cell lines either of the B cell lineage or of other hematopoietic or non-hematopoietic origin. This exclusive expression of BLR1 and the oncogenic potential of this receptor class supports the hypothesis that BLR1 exerts a regulatory function in BL lymphomagenesis and/or B cell differentiation. Moreover, the protein sequence is highly related to that of receptors for the cytokine interleukin (IL)-8 and other neutrophil chemoattractants. We conclude that BLR1 may represent a potential candidate involved in the process of physiologic trafficking, cell-cell interactions, and activation of mature B lymphocytes in lymphatic tissues.
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PMID:Differentiation-specific expression of a novel G protein-coupled receptor from Burkitt's lymphoma. 142 7

Oncogene amplification has been observed in a broad spectrum of human tumors and has been associated with a poor prognosis for patients with several different types of malignancies. Importantly, at biopsy, the amplified genes localize to acentric extrachromosomal elements such as double-minute chromosomes (DMs) in the vast majority of cases. We show here that treatment of several human tumor cell lines with low concentrations of hydroxyurea accelerates the loss of their extrachromosomally amplified oncogenes. The decreases in MYC copy number in a human tumor cell line correlated with a dramatic reduction in cloning efficiency in soft agar and tumorigenicity in nude mice. No effect on gene copy number or tumorigenicity was observed for a closely related cell line containing the same number of chromosomally amplified MYC genes. One step involved in the accelerated loss of extrachromosomal elements is shown to involve their preferential entrapment of DMs within micronuclei. The data suggest that agents that accelerate the loss of extrachromosomally amplified genes could provide valuable tools for moderating the growth of a large number of human neoplasms.
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PMID:Elimination of extrachromosomally amplified MYC genes from human tumor cells reduces their tumorigenicity. 151 43

Expression of c-myc protein was studied immunohistochemically in colorectal cancers using a monoclonal antibody, MYC-1. Immunoblotting assays with cellular lysates demonstrated a band of the gene products at the level of 60 kDa. c-myc-protein-positive tumor cells were observed in 43 (43.4%) of 99 specimens of colorectal cancers. There was no significant correlation between the incidence of MYC-1-positive tumors and clinicopathological findings. The rate of MYC-1 proteins occurring in patients with liver metastasis was significantly higher than that in patients without the metastasis. The rate of occurrence of DNA polymerase-alpha-positive cells in MYC-1 protein-positive tumors was significantly higher than in MYC-1 negative ones. The results suggested that MYC-1 immunoreactivity might possibly be a useful prognostic marker of colorectal cancers.
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PMID:Immunohistochemical detection of c-myc products in colorectal cancer and proliferative cell rate. 154 92

Genetic alterations of multiple loci that serve as markers for the induction and progression of disease have been identified in several adenocarcinomas, but not in adenocarcinoma of the prostate. To determine if similar genetic alterations occur in prostate carcinoma and could serve as markers for the extent of clinical disease, we have examined 23 predominantly moderately-differentiated, localized prostate carcinomas and one prostatic dysplasia for changes in the structure and copy number of ten selected genes. These genes include 1) those important to androgen metabolism in the prostate, the androgen receptor and steroid 5 alpha reductase genes; 2) those that map to the 10q (PLAU) and 7q (MET) chromosomal regions found deleted in some prostate carcinomas, and 3) proto-oncogenes (ERBB2, INT2, and MYC) and tumor suppressor gene loci (RB1, TP53 and D17S5) found altered in adenocarcinomas of the breast, colon and lung. Gene alterations were detected in one specimen, a lymph node metastasis from a poorly differentiated tumor. This specimen exhibited loss of heterozygosity for two loci putatively active in tumor suppression, TP53 and D17S5, on the short arm of chromosome 17. This study indicates that gross genetic alterations were not evident and could not be used as markers of tumor development in well- or moderately-differentiated, localized lesions, but that loss of the 17p region may be a useful marker for advanced carcinomas in the prostate.
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PMID:Loss of the 17p chromosomal region in a metastatic carcinoma of the prostate. 155 12

ABL-MYC, a murine retrovirus that encodes the v-abl and c-myc oncogenes, was constructed from Abelson murine leukemia virus (A-MuLV) in order to assess the biological consequences of co-expression of these genes in lymphoid cells. When inoculated into mice this retrovirus induced plasmacytomas in up to 100% of infected mice and less frequently induced pre-B lymphomas. Both tumor types contained genome-length proviruses in one or a few chromosomal locations, were mono- or oligoclonal as judged by immunoglobulin gene rearrangement and had unrearranged endogenous c-myc loci. The type of tumor induced depended upon the age and strain of mouse, and whether helper virus was present in the inoculated virus pool. ABL-MYC induced plasmacytomas with or without helper virus, with or without pretreatment of the mice with pristane, and in strains of mice resistant to pristane-induced plasmacytomas. Pristane treatment prior to ABL-MYC infection shortened the latent period of plasmacytomagenesis and produced mostly IgM-secreting tumors rather than IgA-secreting tumors, which predominantly arose in the absence of pristane. Control viruses for ABL-MYC with either a deletion in v-abl or a frameshift mutation in c-myc caused predominantly monocyte/macrophage tumors and pre-B-cell lymphomas respectively. Histopathological analysis of ABL-MYC-infected mice showed foci of transformed plasma cells as early as 14 days after infection. These results indicate that v-abl and c-myc act synergistically to transform mature B cells with high efficiency.
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PMID:A retrovirus that expresses v-abl and c-myc oncogenes rapidly induces plasmacytomas. 156 79


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