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Query: UMLS:C0024623 (gastric cancer)
 36,219 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two types of gastric adenocarcinoma can be distinguished histopathologically: the diffuse and the intestinal type. Molecular pathology supports this theory by showing differences in the genetic pathways of both tumor types. In addition to known pathomorphological factors of prognosis, e.g., depth of tumor infiltration, number of lymph node metastases and resection margins, a few genes have been suggested to have prognostic impact in gastric carcinoma. Clinically relevant molecules whose expression or structure is altered include the plasminogen activator (uPA) and its inhibitor PAI-1 (plasminogen activator inhibitor type 1), the cell cycle regulator cyclin E, epidermal growth factor (EGF), the apoptosis inhibitor bcl-2, the cell adhesion molecule E-cadherin, and the multifunctional protein beta-catenin. Gene amplification and protein overexpression of the growth factor receptors c-erbB-2 and K-sam may be prognostic factors for intestinal-type and diffuse-type gastric cancer, respectively. In addition, genetic instability is commonly seen. There has long been evidence for a genetic predisposition to gastric cancer by epidemiological studies and case reports. Very recently, germ line mutations of E-cadherin have been identified that are responsible for a dominantly inherited form of diffuse-type gastric cancer and could be used to identify individuals that are at high risk.
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PMID:Gastric adenocarcinoma: pathomorphology and molecular pathology. 1131 54

The significance of urokinase-type plasminogen activator (uPA) expression in gastric cancer development was tested by using a human uPA cDNA transfection approach and an in vivo severe combined immunodeficient (SCID) mouse model. The AGS gastric cancer cell line, which has urokinase-type plasminogen-activator receptor (uPAR) but lacks uPA, was transfected with a plasmid containing human uPA cDNA and injected into the backs of SCID mice. Compared with the parent AGS cells, uPA protein secretion in AGS-2-, AGS-4-, and AGS-8-transfected cells increased by 26.1-, 34.6-, and 4.8-fold, respectively (P < 0.05). mRNA expression levels of uPA in the AGS-4 clone were much stronger than those in AGS-2 and AGS-8 clones. After the cancer cells (2 x 10(6)) were injected s.c. into the SCID mice, a palpable mass was observed at the injection site at around 140 days post-injection, followed by accelerated growth of the xenograft up to 180 days post-injection only in the high uPA-producing clone (AGS-4). These results suggest that continuous and high production of uPA by tumor cells is one of the important factors reflecting the malignancy of gastric cancer cells.
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PMID:Overexpression of urokinase-type plasminogen activator in human gastric cancer cell line (AGS) induces tumorigenicity in severe combined immunodeficient mice. 1185 78

Oligosaccharide moieties of glycoproteins are structurally altered during development, carcinogenesis, and malignant transformations. It is well known that beta1-6 GlcNAc branching, a product of UDP-GlcNAc alpha-mannoside beta1-6-N-acetylglucosaminyltransferase (GnT-V), is associated with malignant transformation as the results of such alterations. However, the mechanism by which beta1-6 GlcNAc branching is linked to metastasis remains unclear, because the identification of specific glycoprotein(s) that are glycosylated by GnT-V and its biological function have not been examined. We herein report that matriptase, which activates both urokinase-type plasminogen activator and hepatocyte growth factor, is a target protein for GnT-V. The overexpression of GnT-V in gastric cancer cells leads to severe peritoneal dissemination in athymic mice, which can be attributed to the increased expression of matriptase. This increase was due to the acquired resistance of matriptase to degradation, since it is glycosylated by GnT-V and a corresponding increase in the active form. These results indicate that this process is a key element in malignant transformation, as the direct result of oligosaccharide modification.
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PMID:Prometastatic effect of N-acetylglucosaminyltransferase V is due to modification and stabilization of active matriptase by adding beta 1-6 GlcNAc branching. 1186 86

BACKGROUND: Some patients with stage IV gastric cancer have a long survival. Host immune response and proteolytic activity in the primary tumor may be associated with outcome in these patients. The purpose of this study was to assess prognostic factors in patients with stage IV far advanced gastric cancer.METHODS: Findings in 26 patients who underwent resection of stage IV gastric cancer were retrospectively analyzed for clinicopathological variables, and for the immunohistochemical expression of human leukocyte antigen (HLA)-DR as an index of host immune response and for expression of urokinase type-plasminogen activator (u-PA) as an index of proteolytic activity in the tumor.RESULTS: Of the 13 clinicopathological and immunohistochemical variables tested by univariate analysis surgical curability, lymph node metastasis, HLA-DR expression, and u-PA expression had a significant influence on survival after surgery. Multivariate analysis showed that surgical curability, HLA-DR expression, and u-PA expression independently influenced survival. Patients positive for HLA-DR expression [HLA-DR (+)] and regative for u-PA expression [u-PA (-)] had the best survival: 25-month median survival and 25% 5-year survival rate. Patients who were HLA-DR (+) and u-PA (+), or HLA-DR (-) and u-PA (-) had a median survival of 10 months, a 1-year survival rate of 46.2%, and a 2-year survival rate of 7.7%. HLA-DR (-) and u-PA (+) patients had the worst survival: 4.5-month median survival and 0% 1-year survival.CONCLUSIONS: These findings suggest that host immune response and proteolytic activity in the primary tumor may determine malignant potential, and that the combination of positive-HLA-DR and negative-u-PA expression in cancer cells may be a predictor of prolonged survival in stage IV gastric cancer patients.
Gastric Cancer 1998 Dec
PMID:Expression of HLA-DR and urokinase-type plasminogen activator in stage IV gastric cancer. 1195 46

Urokinase plasminogen activating system (PA system) and vascular endothelial growth factor (VEGF) were recently suggested to contribute synergistically to tumor progression. To evaluate the roles of the PA system and VEGF in gastric cancer, the effects of the PA system and VEGF on tumor angiogenesis and the survival of patients with gastric cancer were investigated. Cancer tissues from 101 gastric cancer patients were assayed immunohistochemically for expression of urokinase-type plasminogen activator (uPA), uPA receptor (uPAR), PA inhibitor-1 (PAI-1) and VEGF protein. The positive rates of uPA, uPAR, PAI-1, VEGF expression were 22.8%, 32.7%, 36.6% and 26.7%, respectively. Positive staining was observed in tumor cells (uPA, uPAR, VEGF), or in both tumor cells and stromal cells (PAI-1). The expressions of uPA, uPAR, PAI-1 and VEGF were significantly correlated with the clinicopathological factors: uPA, depth of tumor invasion, differentiation, lymphatic and vascular invasion; uPAR, tumor size, depth, lymph node involvement, differentiation, vascular invasion; PAI-1, tumor size, depth, lymph node involvement, differentiation, vascular invasion; VEGF, differentiation, vascular invasion. The microvessel density (MVD) assessed immunohistochemically was significantly higher in the patients with expression of uPA, uPAR or VEGF, and stepwise analysis identified uPA as an independent correlated factor with MVD. Furthermore, multivariate analysis demonstrated that depth of tumor invasion, lymph node involvement and uPA expression were independent prognostic factors. uPA is a key factor in the PA system, being associated with a poor outcome of gastric cancer, and contributing not only to invasive activity, but also to angiogenesis.
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PMID:Urokinase-type plasminogen activator expression correlates with tumor angiogenesis and poor outcome in gastric cancer. 1270 73

The levels of urokinase (uPA) and tissue type (tPA) plasminogen activators and their type 1 inhibitor (PAI-1) were determined by immunoassay in tumor cytosols and samples of histologically unaltered adjacent mucosa in gastric cancer patients. Gastric tumor revealed enhanced uPA and PAI-1 matched by decreased tPA in intact mucosa. The expression of uPA and PAI-1 was particularly was high at the later stages of the disease. The concentrations of uPA in tumor tissue increased with age. No significant correlation was established between levels of plasminogen activation system components, on the one hand, and histopathological grading of tumor, on the other.
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PMID:[Urokinase and tissue type plasminogen activators and their type-1 inhibitor (PAI-1) in gastric cancer]. 1278 98

The catalog of gene alterations in human cancer grows rapidly. Gastric cancer is no exception and displays gene changes in multiple oncogenes, suppressor genes, and DNA repair genes. Clinically relevant molecules whose expression or structure is altered include the plasminogen activator (uPA) and its inhibitor PAI-1 (plasminogen activator inhibitor type 1), the cell-cycle regulator cyclin E, epidermal growth factor (EGF), the apoptosis inhibitor bcl-2, the cell adhesion molecule E-cadherin, and the multifunctional protein beta-catenin. In addition, genetic instability is commonly seen. Gene amplification and protein overexpression of the growth factor receptors c-erbB2 and K-sam may be prognostic factors for intestinal-type and diffuse-type gastric cancer, respectively. The clinical implications of some of the recent findings for diagnosis and therapy are discussed.
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PMID:Molecular mechanisms of carcinogenesis in gastric cancer. 1279 Mar 21

In our search for genes associated with gastric cancer progression, we identified macrophage inhibitory cytokine-1 (MIC-1), a member of the transforming growth factor beta superfamily, as an overexpressed gene in gastric tumor tissues. Expression analysis of MIC-1 in gastric tumor tissues revealed a specific expression in gastric cancer cells, and this expression level was well correlated with invasive potential in various human gastric cancer cell lines. Stable transfection of MIC-1 into SNU-216, a human gastric cancer cell line, significantly increased its invasiveness. The overexpression of MIC-1 into SNU-216 cells significantly increased the activity of urokinase-type plasminogen activator (uPA), and the expressions of uPA and urokinase-type plasminogen activator receptor (uPAR). Similarly, the stimulation of gastric cancer cell lines with purified recombinant MIC-1 dose-dependently increased cell invasiveness, uPA activity, and uPA and uPAR expression. However, MIC-1 did not significantly suppress the proliferation of gastric cancer cell lines. We also found that the stimulation of human gastric cell lines with recombinant MIC-1 strongly induced activation of mitogen-activated protein kinase kinase-1/2 and extracellular signal-regulated kinase-1/2. Additional analysis revealed that PD98059, a selective inhibitor of mitogen-activated protein kinase kinase-1/2, suppressed not only gastric cancer cell invasiveness and uPA activity, but also the mRNA expressions of uPA and uPAR, as induced by recombinant MIC-1. Our results indicate that MIC-1 may contribute to the malignant progression of gastric cancer cells by inducing tumor cell invasion through the up-regulation of the uPA activation system via extracellular signal-regulated kinase-1/2-dependent pathway.
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PMID:Macrophage inhibitory cytokine-1 induces the invasiveness of gastric cancer cells by up-regulating the urokinase-type plasminogen activator system. 1290 45

The interaction between the urokinase receptor (uPAR) and its ligand urokinase (uPA) mediates phenomena such as tissue remodelling, chemotaxis, tumour invasion, dissemination, proliferation, and angiogenesis. The broad-spectrum of biological processes that the uPA/uPAR interaction plays a role in has led researchers to speculate that this interaction may be a useful molecular target for therapeutic intervention in several pathological conditions, particularly in the prevention and inhibition of the dissemination of cancer cells. In syngeneic and xenograft murine tumour models, in which metastasis is driven by the uPA/uPAR interaction, inhibition of primary tumour growth, metastasis and angiogenesis has been shown with several proteins acting as uPAR antagonists. Immunohistochemistry, in conjunction with prognostic studies, has implicated the uPA/uPAR interaction in the dissemination of tumours, such as malignant melanoma, colon cancer, non-small cell lung cancer (NSCLC) and stomach cancer, as well as breast and ovarian carcinomas. A potential inhibitor of the uPA/uPAR interaction should result in a significant increase in the disease-free interval and survival time following resection of the primary tumour in a clinical Minimal Residual Disease (MRD) setting. Low molecular weight uPAR antagonists should be orally active, and have few side-effects, excellent bioavailability, favourable pharmacokinetic properties and a long half-life. Furthermore, these compounds should be able to inhibit the dissemination of cancer cells without the need for targeted drug and vector delivery.
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PMID:Urokinase receptor antagonists: novel agents for the treatment of cancer. 1599 80

Blockade of angiogenesis is a promising strategy to suppress tumor growth, invasion, and metastasis. Vascular endothelial growth factor (VEGF), which binds to tyrosine kinase receptors [VEGF receptors (VEGFR) 1 and 2], is the mediator of angiogenesis and mitogen for endothelial cells. Cyclooxygenase-2 (COX-2) plays an important role in the promoting action of nicotine on gastric cancer growth. However, the action of nicotine and the relationship between COX-2 and VEGF/VEGFR system in tumorigenesis remain undefined. In this study, the effects of nicotine in tumor angiogenesis, invasiveness, and metastasis were studied with sponge implantation and Matrigel membrane models. Nicotine (200 microg/mL) stimulated gastric cancer cell proliferation, which was blocked by SC-236 (a highly selective COX-2 inhibitor) and CBO-P11 (a VEGFR inhibitor). This was associated with decreased VEGF levels as well as VEGFR-2 but not VEGFR-1 expression. Topical injection of nicotine enhanced tumor-associated vascularization, with a concomitant increase in VEGF levels in sponge implants. Again, application of SC-236 (2 mg/kg) and CBO-P11 (0.4 mg/kg) partially attenuated vascularization by approximately 30%. Furthermore, nicotine enhanced tumor cell invasion through the Matrigel membrane by 4-fold and promoted migration of human umbilical vein endothelial cells in a cocultured system with gastric cancer cells. The activity of matrix metalloproteinases 2 and 9 and protein expressions of plasminogen activators (urokinase-type plasminogen activator and its receptor), which are the indicators of invasion and migration processes, were increased by nicotine but blocked by COX-2 and VEGFR inhibitors. Taken together, our results reveal that the promoting action of nicotine on angiogenesis, tumor invasion, and metastasis is COX-2/VEGF/VEGFR dependent.
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PMID:Nicotine induces cyclooxygenase-2 and vascular endothelial growth factor receptor-2 in association with tumor-associated invasion and angiogenesis in gastric cancer. 1631 86


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