Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0699790 (colon cancer)
 28,837 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have studied the expression of oncogene-encoded mRNAs in a rat model of colon cancer. In this model, rats are intrarectally administered several low doses of the direct-acting carcinogen, N-methyl-N-nitrosourea (MNU). Tumors, predominantly adenomas, develop 5-7 months following administration of the carcinogen, and many of these progress to carcinomas. Upon assaying the steady-state levels of oncogene-encoded transcripts in normal rat colon, we found that fos and N-myc are highly expressed; H-ras, K-ras, myc, myb, and neu messages are present at lower levels; and N-ras, abl, and raf mRNAs are absent. When we compared transcript levels in rat tumors to those in normal colons from the same animal, we observed a 2-4 fold increase in both myc- and H-ras-encoded mRNAs and a 2-7 fold increase in myb message, but no change in expression of any of the 7 other genes. To test whether this increased expression is related to tumor production or is simply a result of the more rapid cellular turnover observed in tumor tissue, the level of oncogene-encoded transcripts was assayed in colonic mucosae of rats given two treatments known to enhance cell turnover and DNA synthesis in the colon. Neither acute application of MNU nor a diet containing 1% cholic acid caused any change in the level of oncogene-encoded mRNAs in rat colons, thus suggesting that the increased abundance of myc, myb, and H-ras messages in tumors is associated with tumor formation. The enhancement of expression of these genes in adenomas, as well as in carcinomas, further suggests that these alterations occur relatively early during the tumorigenic process.
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PMID:Enhanced expression of oncogene-encoded mRNA in a rat model of colon cancer. 201 8

We analyzed amplification, rearrangement and point mutation of the c-erbB2 oncogene about 10 cases of the stomach cancer and 30 cases of the colon cancer. Rearrangement and amplification of the c-erbB2 oncogene were found in one case of moderately differentiated tubular adenocarcinoma of the stomach. According to the restriction map, the rearrangement apparently occurred in the region from the 5' promotor to the extracellular domain. In this case, it appeared that the over expression of ErbB2 oncoprotein detected by immunohistochemical staining was associated with rearrangement of the gene. Thus it was suggested that the point mutation of the transmembrane domain, which has been demonstrated in the rat protooncogene neu, a homolog of human c-erbB2, was not detected in this case.
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PMID:[Rearrangement of the c-erbB2 oncogene--analysis of the gastrocolic carcinoma]. 788 65

Epithelial cells can be detected in bone marrow or peripheral stem cell preparations of patients with various kinds of cancer and their presence in bone marrow is of prognostic significance. Characterization of these cells has been hampered by their low frequency. Here we present a method that may allow sequential immunophenotyping and genotyping of epithelial cells in bone marrow. To simulate in vivo situations, cells from the colon cancer cell line HT29 were seeded into bone marrow and were first detected by the Fab fragment of the A45-B/B3 anticytokeratin antibody. Expression of Ki67, p53, Her-2/ neu (c-erbB2), and 17-1A could be detected on A45-B/B3-stained cells by immunofluorescence using a fluorescein-labeled anti-mouse immunoglobulin specific for the Fc part of mouse immunoglobulins. Reactivity for all antigens except for Ki67 persisted after A45-B/B3 labeling even when a scoring step for the presence of epithelial cells was performed before proceeding with the immunophenotyping. After immunophenotyping, numerical chromosomal aberrations and amplifications of the Her-2/neu oncogene could be assessed by fluorescence in situ hybridization in the same A45-B/B3-stained cells. This combination of immunophenotyping and genotyping may help in establishing the role of epithelial cells in bone marrow or peripheral stem cell harvests for tumor relapse and formation of metastases.
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PMID:Sequential immunotyping and genotyping of tumor cells in bone marrow of cancer patients: a model study. 984 46

Few cases of anti-colon cancer specific T lymphocytes have been described so far. Moreover, the majority of these effectors were generated in vitro by stimulating PBMC from patients or healthy donors with peptides that were derived from proteins expressed and/or secreted by colon cancer tissue such as CEA, Mucin or Her-2/neu. The aim of our study was to evaluate the immunogenicity of colorectal carcinomas in an autologous setting. We exploited the antigen processing and presentation capacity of dendritic cells (DC) to establish an in vitro autologous system that can bypass the need of obtaining cultured tumor cells. DC were generated from the adherent monocyte fraction of PBMC taken from stage II/III colorectal cancer patients. A single cell suspension was prepared by mechanical and enzymatic disruption of the surgical specimens immediately after resection. DC were loaded with autologous tumor lysate, obtained by repeated freezing and thawing, before being used as stimulators for autologous PBL. HLA-class II restricted T cells that recognize the autologous tumor could be generated in a proportion of patients. The fine specificity of the anti-tumor T cells indicates that differentiation as well as tumor restricted antigens are expressed in colon cancer and that these antigens can evoke a class II HLA-restricted response in an autologous setting. Altogether these findings may open a new perspective for a DC based vaccination of colon cancer patients.
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PMID:T cell responses in colorectal cancer patients: evidence for class II HLA-restricted recognition of shared tumor-associated antigens. 1109 21

We report the immunological characterization of three colon carcinoma cell lines, COLO 205, SW620 and SW403, which we selected to combine with cytokine-secreting fibroblasts for the development of an allogeneic tumour cell vaccine. The cell lines expressed HLA-A2 as well as shared tumour-associated antigens (TAAs) representative of colon carcinomas: CEA, Ep-CAM, MUC1, HER2/neu and MAGE antigens. They did not secrete high levels of the immunosuppressive factors TGF-beta, IL-10 or prostaglandins. The lines presented TAAs in a manner recognized by immune effector cells, which was demonstrated by the lysis of SW620 by HLA-A2-restricted anti-p53 cytotoxic T lymphocytes (CTL). COLO 205 and SW620 were genetically modified to express the co-stimulatory molecule CD80 (B7.1), which increased the ability of the cells to stimulate CTL in vitro. CTL clones derived from HLA-A2+ peripheral blood mononuclear cells stimulated with the CD80-expressing lines lysed the stimulator cell and an HLA-A2+ colon cancer cell line, but did not lyse an isogeneic fibroblast line or an HLA-A2- colon cancer cell line. CTL clones derived from colon carcinoma patients immunized with an allogeneic vaccine containing these lines demonstrated killing of autologous tumour cells, the vaccine cell lines and other HLA-A2+ colon cancer cell lines, but not fibroblasts isogeneic to certain of the target cell lines. Our studies demonstrate that these colon carcinoma cell lines express shared TAAs that can induce CTLs which recognize and lyse other colon carcinoma cells, and support the continued clinical evaluation of the CD80 gene modified allogeneic colon cell/cytokine-secreting fibroblast carcinoma vaccine.
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PMID:Antigenic and immunologic characterization of an allogeneic colon carcinoma vaccine. 1210 28

The advent of monoclonal antibodies targeted at tumor associated or tumor specific antigens provides a novel approach for the treatment of a broad range of malignancies. Such targeting agents can either be used as unlabeled molecules to induced antibody dependent cytotoxicity, or complement mediated lysis and/or apoptosis, or be conjugated with cytotoxic moieties such as toxins and/or radioactive nucleids. The applicability of this strategy has been expanded beyond the treatment of NHL as demonstrated by the clinical application of the chimeric monoclonal antibody directed at the Her2/neu receptor in breast cancer, the epidermal growth factor receptor in colon and head/neck cancer, and the vascular endothelial growth factor in lung and colon cancer, among others. In a variety of settings this strategy demonstrates clinical anti-tumor activity in patients who have failed to respond to or are refractory to conventional cytotoxic chemotherapy. Furthermore, given the modest toxicity of these naked antibodies, they avail themselves as ideal partners for combining with conventional chemotherapy to produce results that often appear to be greater than additive. With the discovery of newer targets and means to manipulate the immunoglobulin molecule to generate tailor made antibody fragments, the field of antibody based targeted therapy of cancer appears to be on the threshold of making major strides in the fight against cancer.
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PMID:Monoclonal antibody therapy of non-Hodgkin's lymphoma: the Rituximab story. 1274 5

HER 2/neu is an important oncogene in breast cancer, but the prevalence and significance of HER 2/neu gene amplification in colon cancer have been poorly documented. We have evaluated HER 2/neu gene amplification and protein overexpression in a series of colon cancers to assess the frequency, concordance and clinical significance of these events. HER 2/neu gene copy number was measured in 154 primary colon tumors, 15 liver metastases and matched normal tissues using a quantitative PCR/ligase detection reaction (LDR) technique developed and validated in our laboratory. HER 2/neu copy number was confirmed by fluorescent in situ hybridization (FISH) in all tumors found to have gene amplification. In an independent and blinded fashion, HER 2/neu expression was assessed in paraffin sections from 139 of the tumor specimens using the HercepTest kit. HER 2/neu gene amplification was observed in 4 (2.4%) of the 169 tumor specimens and in none of the normal tissues. There was no apparent association with stage of disease, tumor grade or patient survival. Among 139 cases evaluated by immunohistochemistry (IHC), HER 2/neu overexpression was seen in 5 cases (3.6%). There was extremely high concordance (kappa = 0.852) between gene amplification and protein overexpression. The low prevalence of HER 2/neu gene amplification and protein overexpression suggests that this oncogene plays an infrequent role in the development and progression of colon cancer. These data indicate that the primary mechanism of dysregulated HER 2/neu expression in colon cancer, as in breast cancer, is gene amplification.
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PMID:HER 2/neu expression and gene amplification in colon cancer. 1276 65

Tyrosine kinase (TK) inhibition has been identified as a promising strategy in the treatment of human malignancies and several synthetic inhibitors have been developed. While the selective blockage of specific TKs is highly effective in vitro, clinical results have been less impressive. It has been suggested that the simultaneous inhibition of multiple TKs might lead to more favorable therapeutic results in vivo. We have therefore performed a systematic analysis of intratumoral TK expression in order to identify potential targets for a simultaneous kinase inhibition. To this end, we have analyzed the protein expression of membrane-associated epidermal growth factor receptor (EGF-R), Her-2/neu, platelet-derived growth factor receptor (PDGF-R), insulin-like growth factor receptor (IGF-R), c-Kit and of cytoplasmatic c-Abl in 500 human tumors of epithelial, stromal and mesenchymal origin by immunohistochemistry, and found a distinct pattern of kinase expression: EGF-R, PDGF-R and c-Abl were expressed in the majority of malignant tumors, whereas c-Kit, Her-2/neu and IGF-R protein expression was considerably less frequent. Overall, the EGF-R protein expression was correlated with PDGF-R, c-Kit and c-Abl immunoreactivity (P = 0.003, P = 0.001 and P < 0.001, respectively). c-Abl was co-expressed with IGF-R and PDGF-R (P = 0.003 and P < 0.001, respectively). Kinase co-expression was also seen in tumor subgroups and was particularly significant in breast cancer where IGF-R protein was expressed together with PDGF-R and c-Abl (P = 0.003 and P = 0.004, respectively), and in colon cancer where PDGF-R was correlated with EGF-R (P < 0.001). With the exception of Her-2/neu expression and age, intra-tumoral TK expression was not associated with parameters such as grading or histological subtypes. Taken together, we have found a specific pattern of kinase co-expression and have identified several potential targets for a tumor-specific multimodal TK inhibition.
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PMID:Expression of tyrosine kinases in human malignancies as potential targets for kinase-specific inhibitors. 1561 59

Within the revolution of molecular biology in cancer, it should be pointed out the role of monoclonal antibodies clinically utilized as if they were "magic bullets". From the works of Kohler and Milstein in 1975 the evolution has been fast and its inclusion in daily clinical practice gradual. Among the more significant there is anti-CD20 that has revolutionized the treatment of lymphomas. Currently, antibodies conjugated with isotopes derived from anti-CD20 have been produced. Trastuzumab antibody against HER2/neu has opened new prospects in the treatment of breast cancer. Cetuximab antibody against EGFR has achieved good results in the treatment of chemotherapy-resistent colon cancer. Bevacizumab is perhaps the most promising antibody against solid tumors, having shown effectiveness as first line therapy in metastatic colon cancer in combination with chemotherapy.
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PMID:[Antibodies against cancer]. 1571 74

Patients undergoing resection of hepatic metastases of colorectal cancer have a high risk of extrahepatic recurrence, most likely caused by early tumor cell dissemination or the manipulation of liver tumors during surgical resection. Using immunocytochemistry, we studied 47 patients for cytokeratin (CK)-positive (+) cells in: a) bone marrow (BM) samples to determine whether tumor cell dissemination had already occurred before surgery; and b) blood samples directly taken from the hepatic vein before and during surgery of liver metastases. In addition, normal and malignant liver tissues were evaluated for markers known to be involved in tumor progression and metastasis [urokinase plasminogen activator (uPA), Her-2/neu, epidermal growth factor receptor (EGF-R)] using sandwich enzyme immunoassays. CK+ cells were detected in the BM of 26/47 patients (55%), in blood samples of 14/47 patients (30%) before surgery and 11/47 patients (23%) during surgery with a median detection rate of 1 (range, 1-14) CK+ cell per 4x10(6) MNC. No CK+ cells were found in 15/47 patients (32%) in any sample studied. Tumor tissue was obtained from 32/47 patients and normal liver tissue from 24/32 patients. While no differences were found for EGF-R and Her-2/neu, a 9-fold higher expression of uPA could be demonstrated in tumor tissue of 20/32 patients (63%) compared to normal liver tissue. When all obtained results were correlated with clinical outcome, neither the detection of CK+ cells nor the expression pattern in the tumor tissue, or the combination of both, was predictive for extrahepatic recurrence or overall survival after a mean observation time of 43 months (range, 26-54 months). Although uPa is overexpressed in liver metastases of colorectal cancer, and dissemination of CK+ cells during surgery of these metastases is a frequent event in colon cancer, these findings do not predict extrahepatic recurrence. Further characterization of single cells, especially those spread during surgery, will help to identify those patients with an increased risk of later relapse.
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PMID:Tumor cell dissemination in colon cancer does not predict extrahepatic recurrence in patients undergoing surgery for hepatic metastases. 1639 68


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