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Query: UMLS:C0699790 (colon cancer)
 28,837 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mucin glycoproteins are major secretory products of the colon and contain O-linked oligosaccharides synthesized on a polypeptide backbone. The initial step in the synthesis of O-linked oligosaccharides is the addition of N-acetylgalactosamine to serine or threonine residues forming the Tn antigen. This substance can then receive additional carbohydrate residues such as sialic acid to form sialosyl-Tn antigen, or galactose to form T antigen. In the colon, the T antigen is an oncodevelopmental cancer-associated antigen but little is known about Tn and sialosyl-Tn expression. The present comparative immunohistochemical study was performed to analyze the expression of these antigens in fetal, normal adult, and malignant colorectal tissues with an aim toward elucidating whether Tn and sialosyl-Tn are also oncodevelopmental colon cancer-associated antigens and to gain insight into the earliest steps of mucin glycosylation in colonocytes. We used three reagents to detect Tn antigen (two monoclonal antibodies ETn1.01 and CU-1, and one lectin Vicia villosa), two reagents to detect sialosyl-Tn (monoclonal antibodies TKH2 and B72.3) and one to detect T antigen (monoclonal antibody AH9-16). Except for occasional reactivity with VVA and CU-1, cells of normal colonic mucosa did not express Tn, sialosyl-Tn, or T antigens. However, in the transitional mucosa immediately adjacent to cancer, all three antigens were expressed (ranging from 35 to 67% of cases depending upon the reagent). In colon cancers, the percentage of cases expressing each antigen were as follows: Tn 72-81%, sialosyl-Tn 93-96%, and T 71%. Unlike T antigen, which was preferentially expressed by moderately well- and well-differentiated adenocarcinomas, both Tn and sialosyl-Tn antigens were expressed by most histological subsets of colon cancers, including poorly differentiated adenocarcinomas and mucinous (colloid and signet ring cell type) carcinomas. The majority of cancers expressed both Tn and sialosyl-Tn, usually in association with T antigen. Only one cancer lacked all three antigens. Fetal colonic mucosal cells expressed all three antigens, particularly in goblet cell mucin. These results indicate that like T antigen, Tn and sialosyl-Tn are oncodevelopmental cancer-associated antigens in the colon. Moreover, Tn and sialosyl-Tn antigens appear to be useful markers of poorly differentiated adenocarcinomas and mucinous carcinomas: two histological subsets that often fail to express other cancer-associated antigens and that are often associated with a poor clinical outcome.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Expression of Tn, sialosyl-Tn, and T antigens in human colon cancer. 290 46

Mucin has been purified from nude mouse xenografts of SW1990 human pancreatic cancer cells. The mucin was eluted at the void volume of Sepharose CL-4B and was of density greater than 1.3 in CsCl gradients. The isolated mucin had a high content of threonine, serine, and proline, with 31% of the amino acid residues O-glycosylated. The average oligosaccharide composition was NeuAc1.8Fuc0.7Gal2.0GlcNAc1.7GalNAc1.4. Polyclonal rabbit antibodies prepared against the purified mucin recognized primarily mucin polypeptide, and there was extensive immunological cross-reaction between SW1990 pancreatic cancer mucin and LS174T colon cancer mucin. However, using carbohydrate-specific monoclonal antibodies, the two mucins were found to differ. SW1990 mucin had more Lewis, sialyl Lewis, and sialyl Lewis activity, while the colon cancer mucin had more sialyl T antigen. Since pancreatic mucins, whether from normal pancreas or pancreatic cancer, have not previously been well characterized, the availability of SW1990 pancreatic cancer mucin may be useful as a model for studying the expressing of organ-specific or cancer-associated antigens.
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PMID:Pancreatic cancer mucin from xenografts of SW1990 cells: isolation, characterization, and comparison to colon cancer mucin. 322 46

Sixty-four consecutive patients who had undergone curative resection for colorectal carcinoma were studied prospectively to evaluate the roles of sequential CEA determinations and independent instrumental follow-up in the early detection of resectable recurrences. Fifty-two of these patients also were submitted to sequential determinations of other tumor antigens: TPA (tissue polypeptide antigen) and Ca 19-9 (colon cancer antigen detected with a monoclonal antibody), for a retrospective evaluation of their utility as markers of recurrent tumors. Twenty-two recurrences were detected in a period ranging from 12 to 72 months (median, 47 months). CEA was the best predictor of recurrence (sensitivity, 90 percent) when compared with the other two markers (TPA sensitivity, 60 percent; Ca 19-9 sensitivity, 20 percent). When compared with the instrumental or biochemical examinations of the follow-up, CEA was still the most sensitive indicator of relapse although the specificity was quite low (78 percent) if minimal significative increases were considered. History and physical examination were more useful than CEA in detecting local recurrences in rectal cancer where the preoperative CEA level was low. A few second-look explorations based solely on small CEA increases failed to demonstrate recurrence or revealed peritoneal carcinomatosis. Selected second-look surgery based on demonstrated recurrences resulted in a resectability rate of 57 percent. A follow-up program based on frequent CEA assays, history, and physical examinations, including rectal, vaginal, and perineal exploration, is proposed. Extensive instrumental investigations should follow when a minimal significative CEA rise is observed, or when history and physical examinations suggest a possible recurrence. Second-look surgery should be evaluated after confirmed or highly suspected diagnosis of recurrence, on the basis of instrumental or clinical examinations.
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PMID:Follow-up of colorectal cancer resected for cure. An experience with CEA, TPA, Ca 19-9 analysis and second-look surgery. 347 Jan 72

The LAI reactivity of a colon organ specific neoantigen (OSN) was recovered from the urine of advanced colon cancer patients. In this study three physico-chemical steps were employed; precipitation by 80% ammonium sulfate, ion exchange, and molecular sieve chromatography. Each isolate was tested for activity and specificity by the direct tube leukocyte adherence inhibition (LAI) assay employing leukocytes from colon and breast cancer patients. The OSN enriched isolate was then used to generate monoclonal antibodies (Mab). Hybridomas were screened by ELISA. One hybridoma designated Bac 18.1 reacted preferentially with colon OSN and not with the urine from normals or patients with breast cancer. Affinity purification of colon OSN was achieved and it was shown to consist of a single band in SDS-PAGE with an apparent molecular weight of 30,000. The eluted polypeptide was specifically reactive in ELISA as well as in the LAI assay.
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PMID:The isolation of colon cancer organ specific neoantigen by the use of the leukocyte adherence inhibition assay and monoclonal antibodies. 375 60

Until now, measurement of human antitumor immunity to organ-specific cancer neoantigen (OSN) by the leukocyte adherence inhibition (LAI) assay depended on using crude extracts of cancer. In this study, a new method is presented to generate and to isolate a highly enriched OSN from spent medium of a lung cancer cell line, NCI-H69, grown in chemically defined medium. Production of large quantities of OSN with minimal contamination by extraneous proteins was possible. Four physicochemical steps were used to give a 1000-fold enrichment of OSN activity: anion-exchange and molecular-sieve chromatography; Blue Sepharose affinity chromatography; and finally anion-exchange high-pressure liquid chromatography. The enriched OSN isolates showed dose-response antigenicity when tested in LAI assay with leukocytes from lung cancer patients but had no antigenicity with leukocytes from control subjects or patients having malignant melanoma, colon cancer, or pancreatic cancer. Cross-reactive antigenicity was observed with leukocytes from patients with breast cancer and slight reactivity with leukocytes from bladder cancer patients. The final isolate from the four-step separation procedure as well as the isolates produced using additional separation techniques consistently had antigenicity at less than 10 ng in blocking LAI and 500 ng in the direct assay and showed components with molecular weights of about 62,000 +/- 3,000 (SD) (p62), 40,000 +/- 3,000 (p40), and 25,000 +/- 1,000 (p25) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The OSN isolates on two-dimensional gels showed p40 to have microheterogeneity (seven spots), with a pl from 6.2 to 7.6, and p62 and p25 as even more basic streaks. The polypeptide bearing the antigenic determinant was not purified, although we tried to separate p62, p40, and p25 to determine whether they carried the OSN determinant. The results of this study are important in showing that an isolate of an organ-specific tumor antigen containing 5 to 13 components, as determined by highly sensitive silver stains and radiolabeled patterns on single and two-dimensional gels, can be used successfully in LAI to measure tumor immune responses.
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PMID:An isolated enriched organ-specific cancer neoantigen of human lung cancer for leukocyte adherence inhibition assays. 388 36

Soluble lung tumor activity as determined by LAI2 was enriched by physicochemical methods from chemically - defined spent medium of a lung cancer cell line (NCI-H69). To identify the polypeptide carrying the antigenic determinant, splenic lymphocytes of BALB/c mice were immunized with the enriched isolate and hybridized with mouse plasmacytoma cells. Eight hybrids were cloned successfully and produced MAbs that immunoprecipitated principally a single chain of Mr 40,000 (p40) as well as minor chains of Mr 25,000 (p25) and Mr 13,000 (p13) which were probably degradation products of p40. On 2D gels, p40 was composed of 7 spots with a p1 of 6.3 to 7.6, which was not altered by neuraminidase digestion. Affinity chromatography with MAb anti-p40 absorbed p40 and LAI activity. The bound and recovered fraction was enriched for p40 and LAI activity. Affinity-purified p40 also contained the previously identified p25 and p13 as well as a Mr 32,000 peptide (p32). MAb anti-p40 was directed to a common framework determinant on p40 since MAb anti-p40 bound to cancer cells from other organs. The comparatively lung cancer organ-specific determinant recognized by leukocytes from lung cancer patients was not recognized by the MAb. Affinity-purified p40 triggered LAI for leukocytes from patients with lung cancer but not for leukocytes from control subjects or patients with colon cancer or malignant melanoma in rigorous blind testing. Crossreactivity was observed with leukocytes from patients with breast cancer. LAI activity of affinity-purified p40 seems unlikely to result from an unidentified impurity. Thus a p40 molecule has been purified that is expressed on the membranes of lung cancer cells and triggers immunologically-mediated LAI.
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PMID:Purification from a human lung cancer cell line of a water soluble molecule mediating leukocyte adherence inhibition for patients with lung cancer. 400 98

Patients with malignant and benign colon disease (59 colon cancer and 96 polyps) were studied by means of tissue polypeptide antigen (TPA) and carcinoembryonic antigen (CEA) tests. The evaluation of the circulating levels of the markers showed that the overall sensitivity for the TPA test was 57.6% and for the CEA test was 55.9%. Their specificities were 89.5% and 94.7%, respectively. The analysis of results indicated no considerable difference between CEA and TPA in detecting individuals with malignant diseases. There was only a slight difference in Dukes stages: in stages A and B, TPA sensitivity was higher than CEA sensitivity. On the contrary, in the group of patients with polyps, more false-positive results were obtained with the TPA test than with the CEA test. Immunohistochemical studies on the small group of patients (12 colon cancers) allowed us to evaluate the relationship between the staining positivity for the anti-TPA and anti-CEA antibodies and the circulating levels of the markers. The staining in some cases was not correlated either with the stage of cancer or the circulating TPA or CEA levels. This fact further shows the need to investigate the mechanism that determines the blood levels of many tumor markers. All the specimens examined were positive for TPA and CEA staining, but they were composed of varying proportion of positive and negative tumor cells. The degree of positivity was frequently variable not only between the specimens but also within the same specimen.
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PMID:Tissue polypeptide antigen and carcinoembryonic antigen in colon tumors: serum levels and immunohistochemical localization. 406 41

Serum tissue polypeptide antigen (TPA) levels were measured in 33 patients with esophageal cancer, 39 with stomach cancer and 50 with colon cancer. At the same time five glycoproteins, namely immunosuppressive acidic glycoprotein (IAP), alpha 1-antichymotripsin (alpha 1-ACT), acid soluble glycoproteins (ASP), sialic acid and carcinoembryonic antigen (CEA), were measured for comparison. The mean TPA values were 59.0 +/- 15.4 U/l in 61 normal subjects, 103.6 +/- 104.2 U/l (positive rate, 24.2%) in esophageal cancer patients, 111.9 +/- 49.8 U/l (71.8%) in stomach cancer patients and 124.8 +/- 195.5 U/l (40%) in colon cancer patients. The serum TPA levels in patients with stomach cancer rose with an increased number of involved lymph nodes and with a higher degree of infiltrative growth and increased with the advancement of tumor growth postoperatively. Serum TPA levels correlated well with those of alpha 1-ACT, IAP and ASP in stomach cancer patients and with those of CEA, ASP and sialic acid in colon cancer, but not in esophageal cancer patients. It is suggested that the serum TPA might represent one of the reactant proteins and/or tumor-associated antigens that appear to be dependent upon the cancer status.
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PMID:[Clinical evaluation of tissue polypeptide antigen in patients with esophageal, stomach and colon cancer]. 648 66

The human colon cancer cell lines HCT 116 (poorly differentiated) and GEO (well differentiated) express the mitogenic peptide transforming growth factor alpha (TGF-alpha). The secretion of TGF-alpha was enhanced by phorbol 12-myristate 13-acetate (PMA), indicating the possible role of protein kinase C (PKC) in the formation of mature TGF-alpha. Cells were metabolically labeled with 35S-cysteine and the formation of the mature 6 kDa TGF-alpha polypeptide from the 17 kDa pro-TGF-alpha precursor was determined. The conversion of pro-TGF-alpha was complete in 2-4 hr with the HCT 116 cells showing faster kinetics of TGF-alpha formation than GEO cells. HCT 116 cells secreted more TGF-alpha than GEO cells and the rate and extent of formation of TGF-alpha was enhanced by PMA in both cell lines. The expression of several PKC isozymes by HCT 116 and GEO cells was examined by immunoblotting. The expression of all isozymes examined was higher in HCT 116 cells compared with GEO cells. Calphostin C, an inhibitor of PKC, reduced the enzyme activity and significantly inhibited the PMA-induced secretion of TGF-alpha by both cell lines. Two agonists of PKC that act on specific PKC isozymes, thymeleatoxin and 12-deoxyphorbol 13-phenylacetate 20-acetate (dPPA), stimulated the release of TGF-alpha into the medium to the same extent as PMA. Since dPPA has been reported to stimulate PKC-beta 1 specifically, our results suggest a potential role for PKC-beta in the processing of pro-TGF-alpha by these 2 human colon carcinoma cell lines.
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PMID:Pro-transforming growth factor-alpha processing in human colon carcinoma cells: role of protein kinase C. 763 77

Several studies indicate that nonsteroidal anti-inflammatory drugs including indomethacin, aspirin, sulindac, and piroxicam reduce the risk of colon cancer. Furthermore, nonsteroidal anti-inflammatory drugs that inhibit the cyclooxygenase (COX) enzyme were shown to inhibit the development of colon cancer in animal models of carcinogenesis. Non-steroidal anti-inflammatory drugs inhibit the enzymatic activity of both the constitutive (COX-1) and inducible (COX-2) isoforms of COX enzyme. We have investigated the expression of COX-1 and COX-2 polypeptides in human colon cancer tissues using immunohistochemistry. Enhanced COX-2 expression was observed in colon cancer tissues from 15 subjects with clinically diagnosed colorectal cancer. Marked COX-2 expression was observed in cancer cells, inflammatory cells, vascular endothelium, and fibroblasts of the lesional tissues compared with the nonlesional and normal colon tissues. The extent and intensity of the immunoreactive COX-2 in cancer cells was much greater than that of the other cell types. In contrast, the expression of COX-1 polypeptide was weak in both normal and cancerous specimens. These data suggest that the enhanced expression of the COX-2 gene in colon cancer tissues may contribute to the enhanced synthesis of prostaglandin E2 by the colon cancer tissues. Enhanced expression of COX-2 may play a role in the pathogenesis of colon cancer. Furthermore, selective inhibition of COX-2 may prove to be more efficacious in the retardation of colon cancer development.
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PMID:Expression of cyclooxygenase-1 and -2 in human colorectal cancer. 764 Nov 94


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