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)

Significant advances have recently been made in a number of areas concerning central nervous system (CNS) neoplasia. Particularly salient are the following: (1) gene amplification is related to increasing grade of human glioma malignancy and occurs in approximately 40% of the most common and most malignant variety of glioma, glioblastoma multiforme (GBM), (2) by far the most commonly amplified gene in glioblastomas is the epidermal growth factor receptor (EGFR) gene, which is amplified in about one third of GBMs, (3) a small percentage of GBMs amplify N-myc or the novel sequence gli, (4) the EGFR gene is rearranged in at least half of gliomas in which it is amplified, and (5) EGFR gene rearrangement results in external domain deletions that yield truncated EGF receptors. Antibodies specific for the mutant EGF receptor fusion junction have been successfully produced and provide stimulating new potential avenues for tumor imaging and therapy. For pediatric CNS neoplasms, only medulloblastoma has been investigated in adequate numbers; a small percentage exhibit amplification of either the N-myc or c-myc genes.
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PMID:Amplified cellular oncogenes in neoplasms of the human central nervous system. 137 22

Operationally specific monoclonal antibodies (MAbs) reactive with tumor but not normal adult tissues offer great potential for diagnosis and therapy of CNS neoplasms. Two targets for specific MAb localization were chosen for this study: (1) glioma-associated gangliosides GM2 [II3NeuAc-GgOse3Cer], GD2 [II3(NeuAc)2-GgOse3Cer], GD3[II3(NeuAc)2-LacCer], 3'-isoLM1 [IV3NeuAc-LcOse4Cer], and 3',6'-isoLD1 [IV3NeuAc,III6NeuAc-LcOse4Cer] and (2) epidermal growth factor receptor (EGFR) variant molecules. Epitopic specificity of isolated ganglioside hybridomas was determined with FAB-MS defined ganglioside standards. All MAb are IgM. Assay of 14 cytologic specimens and 31 frozen sections of primary CNS neoplasms revealed staining with anti-GD3 (14/14, 31/31), anti-GM2 (9/14, 26/31), and anti-GD2 (6/14, 24/30), respectively. 3'-isoLM1 and 3',6' isoLD1, which exhibit a restricted oncofetal expression pattern and are not detectable in adult human brain, are present in 15/31 primary CNS neoplasms and in 1/8 human glioma xenografts, as detected by MAbs SL-50 and DMAb-14, respectively. EGFR proteins, the second target, have unique amino acid spans resulting from gene deletion in the amplified EGFR gene present in subsets of malignant human gliomas. Antibodies against EGFR deletion-mutant Type III show highly restricted activity with a subset of glioma biopsies (6/35) expressing the mutant EGFR. These reagents should be useful for in vitro and in vivo diagnosis and, potentially, for treatment of malignant brain tumors.
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PMID:Monoclonal antibodies to malignant human gliomas. 138 25

Overexpression of a transforming growth factor alpha (TGF-alpha) transgene induced the development of liver tumors in 69 of 93 (74%) adult male mice. To identify factors associated with oncogenesis, liver tumors from transgenic animals were characterized at the molecular level. TGF-alpha RNA transcripts were elevated in 17 of 25 (68%) liver tumors, relative to adjacent nontumorous tissue. Expression of the endogenous c-myc and insulin-like growth factor II genes was enhanced in 7 of 19 (37%) and 12 of 16 (75%) tumors, respectively. In contrast, epidermal growth factor receptor RNA levels were unchanged or reduced in all liver tumors, and mutations were not detected in either the Ha-ras or Ki-ras genes. The occurrence of liver tumors in castrated TGF-alpha transgenic mice was reduced about 7-fold, while in ovariectomized transgenic animals the incidence was increased about 6-fold. The progeny of a cross between CD1-derived TGF-alpha transgenic (MT42) and C57BL/6 mice exhibited no reduction in tumor burden (83%); however, the incidence of tumor formation in MT42 x FVB/N offspring was substantially lower (19%). We conclude that in these transgenic mice TGF-alpha promotes tumor formation and appears to play a major role in tumor progression. Moreover, other factors that may collaborate in TGF-alpha-induced hepatocarcinogenesis include c-myc, insulin-like growth factor II, sex hormones, and the genetic background upon which the transgene operates.
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PMID:Molecular and genetic analysis of liver oncogenesis in transforming growth factor alpha transgenic mice. 139 22

Results of recent studies indicate that cultured, androgen-independent prostatic carcinoma cells synthesize and secrete transforming growth factor alpha, which interacts with epidermal growth factor receptors (EGFRs) to promote autonomous growth. In the present study, we evaluated the expression and constitutive activation of EGFRs in normal prostatic epithelial cells and the androgen-independent prostatic carcinoma cell lines PC3 and DU145. Our studies showed that cultured normal epithelial cells and androgen-independent prostatic carcinoma cells actively synthesize and exhibit constitutive phosphorylation of the M(r) 170,000 EGFR. The addition of monoclonal anti-EGFR reduced receptor phosphorylation and significantly inhibited the proliferation of prostatic tumor cells. The observed reduction in EGFR phosphorylation could be partially attributed to an antibody-induced decrease in the expression of metabolically labeled EGFR. Results of further studies showed that anti-EGFR enhanced the sensitivity of PC3 cells to the cytotoxic and cytostatic effects of tumor necrosis factor alpha. These studies demonstrate that constitutive activation of EGFR in androgen-independent prostatic carcinoma plays a functional role in the regulation of cellular proliferation in vitro. In addition, the enhanced sensitivity of prostatic carcinoma cells to tumor necrosis factor alpha in the presence of anti-EGFR provides a rationale for the further investigation of combination therapy in the treatment of disseminated, androgen-independent disease.
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PMID:Epidermal growth factor receptor monoclonal antibody inhibits constitutive receptor phosphorylation, reduces autonomous growth, and sensitizes androgen-independent prostatic carcinoma cells to tumor necrosis factor alpha. 139 16

Experimental evidence suggests that human breast cancer cells can be regulated by the IGF-I and IGF-II present in the tumor stromal elements and/or by the endogenous tumor cell IGF-II in a paracrine or autocrine fashion. Thus, blockade of the receptor signalling pathway could lead to diminished tumor growth. Blockade of the type I IGF receptor by a monoclonal antibody (alpha IR3) has been used as a strategy to demonstrate the importance of the IGF pathway. Although alpha IR3 could not block serum-free growth of breast cancer cell lines, it could inhibit anchorage independent growth in most cell lines in the presence of serum. In vivo, alpha IR3 administered at the time of tumor cell inoculation could inhibit MDA-MB-231 tumor formation in athymic mice; however, inhibition of established tumors was not seen. Moreover, alpha IR3 could not inhibit tumor formation of the MCF-7 cell line in vivo. These results suggest that blockade of the type I IGF receptor can inhibit the growth of some breast cancer cells both in vitro and in vivo. Future anti-growth factor strategies include the combination of anti-IGF receptor antibodies with IGF neutralizing modalities, the dual blockade of growth factor receptors (epidermal growth factor receptor and type I IGF receptor), and combinations of steroid hormone antagonists and anti-growth factor treatments to maximize tumor inhibition.
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PMID:Interference of the IGF system as a strategy to inhibit breast cancer growth. 142 19

In vivo and in vitro studies performed on the polar solvent N-methylformamide (NMF), as well as on its association with chemotherapeutic agents or X rays, have clearly demonstrated that this compound is capable of inducing changes in biological characteristics of tumor cells, e.g., cell differentiation. However, the mechanism of action of NMF is far from being elucidated. Hence, in order to better clarify such a mechanism an in vitro study was carried out by using mouse fibroblasts in primary culture (MEF) and human melanoma cultured cells (M14). Results obtained by immunocytochemical and ultrastructural methods with doses of NMF ranging from 0.1 to 7% are reported here. As a general rule, a different sensitivity (in terms of cytopathologic changes induced by NMF) was found between the cell types considered. In fact, melanoma cells appeared to be highly susceptible to the action of the drug, undergoing severe morphological modifications represented mainly by a reversible dose and time-dependent cell rounding and surface blebbing. In contrast, NMF-induced injury in MEF cells was characterized mainly by a simple retraction of the cell body. A cytochemical analysis of the expression of certain membrane antigens (e.g., glycoproteins, epidermal growth factor receptor, B2 microglobulin) in NMF-treated M14 cells undergoing blebbing was also carried out. A randomly distributed labeling of such molecules was observed. Accordingly, freeze-fracturing electron microscopic analysis also displayed a random distribution of intramembrane particles over the plasma membrane. When subcellular changes induced by the drug were investigated, a remarkable modification of cytoskeletal components was detected in both cell types. In particular, cross-linked actin microfilament bundles were easily observed in NMF-exposed MEF cells. Finally, when different experimental conditions which perturb calcium ion homeostasis or restore protein thiol group reduced state were analyzed, a noticeable impairment of the blebbing phenomenon was observed. Thus, a target effect of NMF on the microfilament system, probably leading, in turn, to several subcellular changes and cell surface blebbing, can be hypothesized. Such a cytoskeletal element-dependent cytopathology appears to be related to changes of the oxidized state of such molecules as well as to calcium ion perturbations.
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PMID:Cytoskeleton-dependent surface blebbing induced by the polar solvent N-methylformamide. 142 60

Between January 1989 and August 1991, 62 patients undergoing resection for colorectal adenocarcinoma were assessed in a prospective fashion on the basis of various tumor characteristics that are thought to indicate prognosis. Parameters measured included epidermal growth factor receptor (EGFr) expression, a cell membrane receptor known to be overexpressed in a variety of tumors, Ki-67, a monoclonal antibody marker of cell proliferation, as well as flow cytometry and standard histologic examination. Statistical analysis included chi square with Yates correction when appropriate, Wilcoxon W, and multivariate logistic regression. EGFr positive tumors were associated with worse Dukes' stage (27% of EGFr negative tumors were Dukes' C or D vs. 58% of EGFr positive tumors, P = 0.03), as well as more aneuploid characteristics by flow cytometry (48% EGFr negative = aneuploid vs. 82% EGFr positive = aneuploid, P = 0.01). Lymphatic invasion was more frequent in EGFr positive tumors (P = 0.03). These factors proved to be independent of each other by multivariate analysis. Ki-67 did not correlate with any of the measured parameters and was of extremely limited use in the evaluation of the study population. Multivariate analysis indicated that aneuploid tumors were associated with worse Dukes' stage than diploid tumors. Histologic parameters such as lymphatic and vascular invasion as well as histologic grade are compared to the other parameters involved with prognosis.
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PMID:Prognostic markers of colorectal cancer: an evaluation of DNA content, epidermal growth factor receptor, and Ki-67. 143 39

Results of numerous studies indicate that both activation of dominant oncogenes and inactivation of tumor suppressor genes play important roles in the genesis and progression of human gliomas. Activation of the epidermal growth factor receptor (erbB1 oncogene) as the result of gene amplification or rearrangement is the best established example of a dominant oncogene involved in glioma development. There is also suggestive evidence for activation of the ros oncogene in gliomas, and activation of a variety of other dominant oncogenes may be operative in individual tumors. Deletion studies suggest that inactivation of tumor suppressor genes on chromosomes 17p (probably the p53 gene), 10, 9p and 22 also play roles in genesis and progression of human gliomas. Additional work remains to be done to identify other dominant oncogenes and tumor suppressor genes involved in gliomas, and to determine how these various factors interact to cause disease.
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PMID:Oncogenes and glial tumors. 144 59

Growth of epithelial ovarian cancer is influenced by several factors including transforming growth factor-alpha and transforming growth factor-beta, macrophage colony stimulating factor, tumor necrosis factor-alpha, interleukin-1 and interleukin-6, c-erb B-2 (HER-2/neu), and mutant p53. Continued expression of the epidermal growth factor receptor, new expression of c-fms, and overexpression of HER-2/neu are associated with a poor prognosis. A number of cytokines have been used to treat patients with ovarian cancer, including interferon-alpha, interferon-gamma, tumor necrosis factor-alpha, and interleukin-2. Judging from preclinical models, interferon-gamma may be more active than interferon-alpha against human ovarian cancer. Although tumor necrosis factor-alpha can stimulate proliferation of some ovarian cancers, the cytotoxic activity of tumor necrosis factor-alpha has been amplified ex vivo by inhibitors of protein synthesis. Similar heterogeneity exists with regard to interleukin-1 where stimulation or inhibition of cell proliferation has been observed. Tumor-infiltrating lymphocytes from ascites fluid contain cells capable of major histocompatibility complex-restricted and major histocompatibility complex-nonrestricted cytotoxicity. Tumor-infiltrating lymphocytes and interleukin-2 have been combined with cytotoxic chemotherapy to treat advanced or recurrent disease. Bispecific monoclonal antibodies that react both with T cells and ovarian tumor cells have produced tumor inhibition in human tumor xenografts. Immunotoxins that contain OVB3 and pseudomonas exotoxin have been evaluated in a phase I clinical trial. Dose-limiting central neurotoxicity has been observed without tumor regression. A monoclonal antibody designated OVX1 has been developed against a high-molecular-weight mucinlike molecule associated with ovarian cancers.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Biology and therapy with biologic agents in gynecologic cancer. 145 11

A purified, size-homogeneous (100 kDa), desialylated form of a truncated, soluble form of the epidermal growth factor receptor secreted by A431 human tumor cells has been found, by isoelectric focusing in immobilized pH gradients, to consist of two major isoforms (with pIs of 6.96 and 6.71), one intermediate form (pI 6.45) and a number (> 10) of minor components. The two major components have been purified to charge homogeneity by isoelectric focusing in a multicompartment electrolyzer with buffering isoelectric membranes having the following pI values: 5.90, 6.63, 6.76, 6.92, 7.05 and 7.35. Such single pI species are presently used for attempts at crystal growing.
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PMID:Purification to single isoforms of a secreted epidermal growth factor receptor in a multicompartment electrolyzer with isoelectric membranes. 145 89


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