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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

About 50-70 mg in total of carcinoembryonic antigen (CEA) (or CEA-related antigens) was detected in normal adult feces evacuated during one day (200-250 g). Ten percent or less of the antigen was found to be in soluble form in fresh feces (naturally solubilized antigen), while 90% or more was still in membrane-bound form which was releasable with phosphatidylinositol-specific phospholipase C (PI-PLC-solubilized antigen). The naturally solubilized and PI-PLC-solubilized antigens are antigenically different from each other and similar to normal fecal antigen (NFA)-2 and CEA, respectively, suggesting that "CEA-distinctive" antigenicity detected so far in CEA from cancerous tissues is not due to the difference between antigens in normal and malignant tissues but is probably due to the presence of the glycosylinositolphosphate moiety at the carboxyl-terminus of the antigen molecule. Thus, "CEA-distinctive" antigenicity is by no means cancer-specific, but this antigenicity seems to be critical for the clinical significance of CEA as a tumor marker, because an assay system (Kit II) which is able to distinguish CEA from NFA-2 revealed much improved features in cancer diagnosis as reported recently.
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PMID:Characterization of carcinoembryonic antigen-related antigens in normal adult feces. 216 22

Forty-four previously diagnosed surgical biopsy specimens of oligodendroglioma with calcification from the file of Veterans General Hospital-Taipei between 1977-1985 form the base of this study. Thirty-two patients (72.8%) had varied degree of calcification deposits in tumor parenchyma related to blood vessels while 12 patients (27.2%) in tumor parenchyma unrelated to blood vessels. Ten patients (22.7%) disclosed calcification at the vicinity of tumor tissue. Histochemical studies of the calcified deposits revealed no trace minerals other than calcium and iron. Electron microscopic examination of the calculi showed membrane-bound vesicles and radially precipitated crystals that simulated hydroxyapatite of psammoma body in meningioma. There was no statistically significant correlation between the demise or recurrence of patients and the calcification of tumor when Chi-squared test was applied.
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PMID:Calcification in oligodendroglioma. 216 57

Malignant spreading of cancer cells requires cell surface proteases that cleave the crosslinked collagenous matrix of connective tissues. From correlating the morphologically defined invasiveness of tumor cells with the presence of specific membrane-associated proteases, we have identified a malignant human melanoma cell line, LOX, that invades crosslinked gelatin films in vitro and contains uniquely a neutral 170-kDa gelatinase in the cell membrane. A similar gelatinase was found in membranes recovered from culture media conditioned with LOX. The 170-kDa gelatinase is a wheat germ agglutinin-binding protein. The proteolytic activity is maximal at neutral pH, enhanced by EDTA and dithiothreitol, inhibited by the cysteine protease inhibitors N-ethylmaleimide, HgCl2, and phenylmethylsulfonyl fluoride, and can bind to an organomercurial adsorbent, suggesting that it is a neutral sulfhydryl-sensitive protease. This 170-kDa gelatinase of LOX cells was not found in a control melanoma cell line, SK-MEL28, or in 32 other tumor cell lines that did not show extracellular gelatin degradation. Thus, we have identified a large membrane-bound protease that may be a specific marker molecule for melanoma cell invasiveness.
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PMID:A 170-kDa membrane-bound protease is associated with the expression of invasiveness by human malignant melanoma cells. 217 80

Cloning and sequencing of epithelial membrane antigen (EMA) has demonstrated the existence of a variable number of tandem repeats (VNTR) flanked by unique sequences, and alternative splicing has been proposed to result in secreted and membrane-bound antigenic forms. Antisense oligonucleotides, specific for the VNTR region and various alternative splice forms, were used as probes to define EMA transcripts in poly A+ RNA from a mucinous breast tumor cell line. The BT549 line has been shown to exhibit enhanced expression and secretion of EMA when the cells are cultivated in a medium supplemented with hydrocortisone and insulin, and Northern blot analysis demonstrated that EMA-related RNA transcripts are commensurately enhanced. As a result of the large increase in EMA RNA levels, two major transcripts in BT549 have been identified as coding for either the secreted or transmembrane EMA forms and two antigenic forms have been immunoprecipitated from BT549 cell layer and medium translation products.
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PMID:Multiple protein forms of the human breast tumor-associated epithelial membrane antigen (EMA) are generated by alternative splicing and induced by hormonal stimulation. 220 2

Several observations indicate that the triggering event for receptor-mediated actin polymerization takes place in or close to the plasma membrane. Stimulation of human neutrophils with the chemotactic peptide formylmethionyl-leucyl-phenylalanine (fMet-Leu-Phe) causes rapid and transient changes in both chlorotetracycline (CTC) fluorescence and the cellular content of filamentous actin (F-actin), thus suggesting a regulatory role for membrane-bound calcium in actin polymerization. In the present study, tetracaine, a proposed antagonist to membrane-bound calcium, totally inhibited the rebinding of the membrane calcium released by fMet-Leu-Phe. This was accompanied by a magnified and sustained increase in the cellular content of F-actin. In agreement, N-ethylmaleimide, an inhibitor of motile functions, completely abolished the fMet-Leu-Phe-triggered changes in both CTC fluorescence and F-actin content and rapidly reversed the responses when added after the peptide. The tumor promoter phorbol-12-myristate-13-acetate, caused only small changes in CTC fluorescence and F-actin content, and reduced a subsequent fMet-Leu-Phe-induced CTC response and actin polymerization. Inhibition of the breakdown of phosphatidylinositol 4,5-bisphosphate, by calcium depletion, had no significant effects on the fMet-Leu-Phe-induced CTC response and alterations in F-actin content, whereas pretreatment with pertussis toxin totally inhibited both these responses. Consequently, the strong correlation between changes in CTC fluorescence and F-actin content, found in this study, suggests a triggering or modulating role of membrane-associated calcium on actin polymerization in human neutrophils.
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PMID:Correlation between chemotactic peptide-induced changes in chlorotetracycline fluorescence and F-actin content in human neutrophils: a role for membrane-associated calcium in the regulation of actin polymerization? 222 51

The biosynthesis and processing of cachetin/tumor necrosis-factor (TNF) were examined in the murine macrophage-like cell line RAW 264.7. Lipopolysaccharide-stimulated cells secreted both glycosylated and nonglycosylated 17-kilodalton (kDa) mature cachectin/TNF into the culture medium. Secreted cachectin/TNF was derived from membrane-associated precursors that were precipitated by polyclonal antisera raised against either the mature protein or synthetic peptide fragments of the 79 amino acid cachectin/TNF prohormone sequence. About half of the precursors were N-glycosylated, apparently cotranslationally. The cachectin/TNF precursors were then proteolytically cleaved to release soluble mature cytokine into the medium, while the membrane-bound 14-kDa presequence remained cell associated. During the period of LPS stimulation, the amount of macrophage cell surface cachectin/TNF remained at a low level, suggesting that both nonglycosylated and glycosylated precursors of cachectin/TNF are efficiently cleaved by these cells. These findings suggest the presence of a unique mechanism for the secretion of cachectin/TNF.
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PMID:Processing of newly synthesized cachectin/tumor necrosis factor in endotoxin-stimulated macrophages. 225 98

Inclusions in the nucleus, compared with those in the cytoplasm, are rare in myeloma cells but have been reported in all electrophoretic varieties of multiple myeloma except the nonsecretory type. In this unusual case, a 54 year old Chinese woman had a pathological fracture of the left femur, and biopsy of the fracture site revealed a round cell tumor compatible with plasmacytoma. A bone marrow aspirate revealed 50% plasma cells, many of which contained intranuclear inclusions. Protein electrophoresis was normal with no paraprotein, and urine was free from Bence-Jones protein. Under electron microscopy, the plasma cells showed electron-dense spherules not circumscribed by a membrane. The absence of a membrane was unusual, because according to all reported cases, these intranuclear inclusions were invariably membrane-bound. The association of nonsecretion of paraprotein in myeloma, which is rare, and the absence of a membrane enclosing the intranuclear inclusions, which is heretofore unreported, is probably not coincidental but causally related in that paraprotein produced in the nucleus of myeloma cells (stored in the form of intranuclear inclusions) fails to be detected in serum and urine because of noninteraction between these inclusions and the membranes of the nucleus and endoplasmic reticulum.
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PMID:Intranuclear inclusions in myeloma cells in a case of nonsecretory multiple myeloma. 217 3

Adenocarcinoma of the rete testis is a rare tumor. We describe the ultrastructural appearance of a retroperitoneal adenocarcinoma metastatic from the rete testis, and compare this appearance with that of normal human rete testis. Both normal rete epithelium and the tumor showed deep, narrow nuclear invaginations with apparent nuclear lobulation; small, pleomorphic, electron-dense, membrane-bound granules in the basal cytoplasm; lipid droplets in the apical cytoplasm; and distinctive bulbous cytoplasmic projections along the apical surfaces of the cells. In addition, more general features of glandular tissue were seen. Features notable for their absence were mucin granules, microvilli containing filamentous cores, glycocalyx, and glycocalyceal bodies. The ultrastructural appearance was sufficiently distinctive to suggest that, in the proper clinical context, electron microscopy may serve to support a diagnosis of adenocarcinoma of the rete testis.
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PMID:Ultrastructure of metastatic rete testis adenocarcinoma. 229 71

A case of peritoneal malignant mesothelioma in a radiation technologist, who had worked in this field for 34 years, is reported. Histopathologically, a biopsy specimen from the retroperitoneal tumor revealed a biphasic type of malignant mesothelioma. Electron microscopy disclosed that the tumor cells contained prominent microvilli, basal laminae adjacent to the stroma, junctional complexes, desmosomes, tonofilaments, clusters of glycogen granules, well developed rough endoplasmic reticulum (RER), confronting cisternae showing direct continuity with the RER and membrane-bound granules suggestive of secretory activity. No increased amount of asbestos was detected in autopsied lung material or the peritoneal mesothelioma. The estimated cumulative dose of occupational irradiation was calculated to be about 40 to 50 rad at most. Irradiation was discussed in relation to the etiology of the peritoneal mesothelioma.
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PMID:An autopsy case of peritoneal malignant mesothelioma in a radiation technologist. 231 72

Complementary DNA clones coding for both carcinoembryonic antigen (CEA), a well characterized colonic tumor marker, and nonspecific cross-reacting antigen (NCA), a related antigen, were expressed in Chinese hamster ovary (CHO) cells and L-cells (mouse fibroblasts). A genomic clone coding for CEA was also expressed in CHO cells. Positive clones were identified by fluorescence flow cytometry and enzyme-linked immunosorbent assay. Membrane location of the recombinant CEA and NCA was confirmed by indirect immunofluorescence labeling of the transfectants, followed by visualization under a fluorescence microscope. The apparent molecular weight of the expressed CEA and NCA were 180,000 and 96,000, respectively, for both cell lines, as determined by immunoblot analysis. The CEA and NCA expressed on CHO cells were sensitive to treatment with phosphatidylinositol-specific phospholipase C (PI-PLC), whereas the CEA and NCA proteins on L-cells were resistant to removal by PI-PLC. Unlike NCA, which contains three methionine residues, the only methionine in CEA is in the C-terminal hydrophobic domain. This domain in CEA was shown to be removed and replaced by a phosphatidylinositol glycan (PI-G) anchor (Hefta et al., Proc. Natl. Acad. Sci. USA, 85: 4648-4652, 1988). The recombinant CEA from both CHO cells and L-cells could be labeled with [3H]-ethanolamine (a component of the PI-G anchor) but not with [35S] methionine, whereas the recombinant NCA could be labeled with both [3H]ethanolamine and [35S]methionine. The labeling studies and PI-PLC treatment results are consistent with the CEA and NCA expressed on CHO cells possessing a PI-G anchor. The CEA expressed on the L-cell transfectants may contain a PI-G anchor which is resistant to cleavage by PI-PLC. In addition, the membrane-bound and secreted levels of CEA from the CHO and L-cell transfectants were determined.
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PMID:Expression of complementary DNA and genomic clones for carcinoembryonic antigen and nonspecific cross-reacting antigen in Chinese hamster ovary and mouse fibroblast cells and characterization of the membrane-expressed products. 231 24


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