Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024623 (gastric cancer)
 36,219 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Programmed cell death (apoptosis) is an active process which is genetically encoded and plays an important role in several cellular activities such as embryonic development, deletion of autoreactive T-cells and homeostasis. Several genes regulating apoptosis have been reported, including p53, one of the tumor suppressor genes, c-myc, one of the proto-oncogenes, and various kinds of Bcl-2 related genes. A new cDNA clone which is homologous to Bcl-2, named as Bfl-1 were isolated from a human fetal liver at 22 week of gestation. This clone was identified by computer analysis of random cDNA sequences that were obtained in an effort to expand the expressed sequence tag (EST) databases to be used for human genome analysis. The homology was recognized by 72% amino acid identity to the murine A1 gene, a member of the Bcl-2-related genes. The homology to the BH1 and BH2 domains of Bcl-2 was especially significant, suggesting that Bfl-1 is a new member of the Bcl-2-related genes. Bfl-1 is abundantly expressed in the bone marrow and at a low level in some other tissues. Interestingly, a correlation was noted between the expression level of Bfl-1 gene and the development of stomach cancer in eight sets of clinical samples. It is conceivable that Bfl-1 is involved in the promotion of the cell survival in the stomach cancer development or progression.
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PMID:A novel Bcl-2 related gene, Bfl-1, is overexpressed in stomach cancer and preferentially expressed in bone marrow. 747 96

Deregulation of bcl-2 may function as a survival mechanism in cancer cells, predisposed to cell death. Aberrant Bcl-2 expression is a frequent occurrence in chronic atrophic gastritis, gastric epithelial dysplasia and gastric cancer. Inhibition of apoptosis through Bcl-2 expression appears to be specifically associated with promotion of gastric adenocarcinoma. In addition, loss of heterozygosity of the bcl-2 gene is a common event in well-differentiated adenocarcinoma, whereas overexpression of bcl-2 gene is observed in poorly differentiated adenocarcinoma. Bax, a homologue of Bcl-2, counters the death repressor activity of Bcl-2. In our study Bax immunostaining in gastric cancer tissue is not significantly correlated with tumor histology. Possible gene therapy using bax gene is discussed.
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PMID:[Expression of Bcl-2 and Bax in human gastric cancer tissue]. 874 90

The apoptosis-regulating proteins Bcl-2, Bax, Bcl-X, Bak, and Mcl-1 were examined by immunohistochemical methods in 48 archival specimens of adenocarcinoma of the stomach, and the results were correlated with tumor histology (intestinal versus diffuse pattern) and clinical stage (early- versus late-stage disease, ie, stages I and II versus stage III). Tumor cells containing immunostaining for the anti-apoptotic proteins Bcl-2, Bcl-X, and Mcl-1 were present in 26 (54%), 41 (85%), and 36 (75%) of the 48 cases evaluated, respectively, whereas immunopositivity for the pro-apoptotic proteins Bax and Bak was found in 44 (92%) and 42 (88%) specimens Comparisons of these immunostaining results with tumor histology revealed statistically significant differences for Bax (P = 0.03), Bcl-X (P = 0.003), and Mcl-1 (P = 0.005), which were all more frequently immunopositive for tumors with an intestinal than a diffuse histological pattern (chi 2 analysis). In addition, the percentage of immunopositive tumor cells was significantly higher for Bcl-X (62 +/- 6% versus 45 +/- 6%, mean +/- SE, P = 0.01) and for Mcl-1 (48 +/- 6% versus 30 +/- 6%; P = 0.04) in tumors with intestinal versus diffuse histology (unpaired t-test). In contrast, the percentage of Bcl-2-immunopositive tumor cells was higher in tumors with diffuse histology compared with intestinal (32 +/- 5% versus 12 +/- 5%; P = 0.01), whereas the percentages of Bax- and Bak-immunopositive tumor cells were not significantly different between these two histological types. In 34 specimens, residual normal gastric epithelial cells (foveolar cells) were present for direct comparisons of immunointensity with tumor cells. The immunointensity for the Bcl-2, Bcl-X, and Mcl-1 proteins was stronger in tumor cells compared with normal foveolar cells in 7 (21%), 15 (44%), and 8 (2.1%) of 34 cases, respectively, whereas the immunointensity of the proapoptotic proteins Bax and Bak was reduced compared with normal cells in 8 (24%) and 24 (71%) cases. Immunointensity, however, did not correlate with histology. clinical stage was not significantly associated with the presence or absence of immunopositive tumor cells, the percentage of immunopositive cells, or immunointensity. Taken together, these results establish for the first time that several Bcl-2 family proteins are expressed in gastric adenocarcinomas and suggest that the repertoire of these proteins may differ depending on the histological type. The findings therefore support the notion that the intestinal and diffuse types of gastric cancer arise at least in part through different mechanisms.
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PMID:Immunohistochemical analysis of Bcl-2 family proteins in adenocarcinomas of the stomach. 890 34

A1, a member of the Bcl-2 gene family, was originally identified as a hemopoietic-specific early response gene. Later it was found that A1 was overexpressed in human stomach cancer tissues and was induced by tumor necrosis factor-alpha (TNF-alpha) in human vascular endothelial cells. However, its expression in human cancer cells has not been well characterized. In the present study, we examined the expression of A1, as well as the antioxidant manganous superoxide dismutase (MnSOD), in four human thyroid carcinoma cell lines, two human pancreatic carcinoma cell lines, and two human prostate carcinoma cell lines. A1 mRNA was expressed in all four thyroid carcinoma cell lines. TNF-alpha induced A1 in a time- and dose-dependent manner. In contrast, A1 mRNA was not detectable in the pancreatic and prostate carcinoma cell lines in the presence or absence of TNF-alpha. However, TNF-alpha induced manganous superoxide dismutase (MnSOD) mRNA in all the cell lines tested. Furthermore, an agonist antibody to the p55 TNF-alpha receptor induced A1, but the agonist antibody against p75 TNF-alpha receptor did not have this effect. The results indicate that A1 is expressed in human thyroid carcinoma cells and TNF-alpha induces A1 through the p55 TNF-alpha receptor-mediated pathway.
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PMID:TNF-alpha induction of A1 expression in human cancer cells. 956 10

Bcl-2 and a Bcl-2-binding protein BAG-1 function in protection from apoptosis induced by a variety of stimuli. Deregulated expression of Bcl-2 leads to inhibition of apoptosis and is correlated with development of various cancers. Here, we provide evidence that prolonged cell survival introduced by overproduction of Bcl-2 or BAG-1 strongly enhances peritoneal dissemination of human gastric cancer MKN74 cells. Gene transfer-mediated overexpression of Bcl-2 or BAG-1 led to prolonged cell survival of MKN74 cells against serum-starved apoptosis and anoikis. When the viable transfectants were inoculated into the intraperitoneal cavity of BALB/c nude mice, the Bcl-2-expressing MKN74 cells and the BAG-1-expressing MKN74 cells exhibited strongly enhanced peritoneal dissemination in BALB/c nude mice and whole disseminated tumor weights were increased by 4-fold and 3.3-fold, respectively, compared with the control transfectants. The enhanced peritoneal dissemination of MKN74-Bcl-2 and MKN74-BAG-1 transfectants correlated well with resistance to cell death induced by serum-starvation and anoikis. However, the overexpression of Bcl-2 or BAG-1 caused no significant difference among the transfectants in cell growth rates, either in vitro or in vivo. Taken together, these studies demonstrate that resistance to apoptosis is a crucial factor for development of peritoneal dissemination of human gastric cancer cells.
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PMID:Prolonged cell survival enhances peritoneal dissemination of gastric cancer cells. 963 44

Bfl-1, a member of the Bcl-2 gene family, blocks p53-mediated apoptosis and has oncogenic transforming activity. In normal tissues, the transcript of Bfl-1 is expressed abundantly in bone marrow and at a low level in several other tissues. In previous experiments, elevated expression of Bfl-1 was observed by Northern analysis of stomach cancer samples. To study the role of Bfl-1 in normal cell development and in tumorigenesis, we have analyzed the expression of Bfl-1 in normal and tumor tissues by the in situ hybridization technique. The Bfl-1 transcript was detected in the white pulp of the spleen and in the germinal center of lymphatic tissues. In tumor tissues, its expression was preferentially detected in infiltrating inflammatory cells rather than in cancer cells, suggesting that Bfl-1 is not involved in tumorigenesis.
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PMID:Expression of Bfl-1 in normal and tumor tissues: Bfl-1 overexpression in cancer is attributable to its preferential expression in infiltrating inflammatory cells. 967 Aug 30

We investigated tissue staining for Bcl-2 and Bax proteins, which regulate apoptosis, as indicators of chemotherapeutic effect in patients with gastric cancer. In 23 patients with gastric carcinoma biopsy specimens were obtained endoscopically prior to chemotherapy and stained immunohistochemically with anti-Bcl-2 and anti-Bax antibodies. Patients then were treated with continuous infusion of 5-FU and cisplatin. No correlation was seen between chemotherapeutic effect and Bcl-2 or Bax alone. However, among the Bax-positive cases, the patients with Bcl-2-positive tumors were significantly more chemoresistant (p = 0.036) and had worse prognoses (p = 0.008) than Bcl-2-negative cases. Therefore, immunohistochemical staining for Bcl-2 protein may predict chemotherapeutic efficacy or guide specific therapeutic choices in treating Bax-positive tumors.
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PMID:Predictive value of Bcl-2 and Bax protein expression for chemotherapeutic effect in gastric cancer. A pilot study. 977 21

The bcl-2 protein has been shown to prevent apoptosis or programmed cell death and may play an important role for the regulation of tumour growth. Although expression of bcl-2 has been shown to correlate with a better prognosis in breast and lung carcinomas, information concerning the prognostic role of bcl-2 in gastric cancer on a considerable number of tumours is still lacking. In the present study, therefore, the expression and prognostic role of the bcl-2 protein was investigated immunohistochemically in 413 curatively resected gastric carcinomas. Bcl-2 expression was detected in 11.4% (n = 47) of the tumours and was significantly associated with the tumour classification according to Lauren (P < 0.001), 95% of the bcl-2-positive tumours being intestinal type, whereas all diffuse type or signet ring cell carcinomas were bcl-2-negative. No correlation was found between bcl-2 expression and the prognostic parameters depth of invasion (pT category), blood vessel and lymphatic vessel invasion. However, well and moderately differentiated tumours were more often bcl-2-positive than poorly differentiated tumours (P < 0.001), and lymph node negative tumours were more often bcl-2-positive than nodal positive tumours (P < 0.006). Concerning survival, there were no statistically significant differences between patients with bcl-2-positive tumours and patients with bcl-2-negative tumours. According to our results on 413 gastric carcinomas, in contrast to breast and lung cancer, bcl-2 expression has no prognostic impact in gastric cancer.
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PMID:Prognostic value of bcl-2 expression in gastric cancer. 989 43

In various types of human malignant tumors, the presence or absence of expression of apoptosis-associated gene products (p53 protein and Bcl-2 protein) and the tumor proliferation activity-related factor (Ki-67) was assessed by immunohistochemical staining and the correlation between this expression and chemosensitivity to anticancer drugs was investigated. Study subjects comprised 55 preoperative patients with untreated malignant tumors (9 with esophageal cancer, 11 with stomach cancer, 11 with colon cancer, 13 with hepatic cancer and 11 with breast cancer). A chemosensitivity test was carried out with the histoculture drug response assay (HDRA) method using 4 drugs, mitomycin C (MMC), 5-fluorouracil (5-FU), doxorubicin hydrochloride (ADM), and cisplatin (CDDP). Immunohistochemical staining was used to assess expression of p53 protein, Bcl-2 protein and Ki-67. The tumor growth inhibition index (I.I.) of the 4 drugs was significantly lower in a group of the patients with p53 protein overexpression-type (mutant p53 protein positive expression-type) tumors than in a group with p53 protein negative expression-type tumors (p<0.05). No significant correlation was found between the expression of the Bcl-2 protein by and the I.I. of any drug studied in any type of cancer. A negative correlation was found between the labeling index (L.I.) for Ki-67 in all cases and I.I. for MMC and ADM and thus, chemosensitivity of the tumors with high growth activity was lower. Furthermore, a positive correlation existed between the L.I. for Ki-67 and that for p53 protein. The patients with p53 protein overexpression-type (mutant p53 protein positive) tumors showed low chemosensitivity. In addition, overexpression of p53 protein is suggested to be one of the factors involved in the lowered chemosensitivity of the tumors with high growth activity. Summarizing these findings, the p53 protein can play an important role in cancer therapy.
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PMID:Usefulness of p53 protein, Bcl-2 protein and Ki-67 as predictors of chemosensitivity of malignant tumors. 1020 14

To prevent neoplasia, cells of multicellular organisms activate cellular disposal programs such as apoptosis in response to deregulated oncogene expression, making the suppression of such programs an essential step for potentially neoplastic cells to become established as clinically relevant tumors. Since the mutation of ras proto-oncogenes, the most frequently mutated proto-oncogenes in human tumors, is very rare in some tumor types such as glioblastomas and gastric cancers, we hypothesized that mutated ras genes might activate a cell death program that cannot be overcome by these tumor types. Here we show that the expression of oncogenically mutated ras gene induces cellular degeneration accompanied by cytoplasmic vacuoles in human glioma and gastric cancer cell lines. Cells dying as a result of oncogenic Ras expression had relatively well-preserved nuclei that were negative for TUNEL staining. An immunocytochemical analysis demonstrated that the cytoplasmic vacuoles are derived mainly from lysosomes. This oncogenic Ras-induced cell death occurred in the absence of caspase activation, and was not inhibited by the overexpression of anti-apoptotic Bcl-2 protein. These observations suggested that oncogenic Ras-induced cell death is most consistent with a type of programmed cell death designated 'type 2 physiological cell death' or 'autophagic degeneration', and that this cell death is regulated by a molecular mechanism distinct from that of apoptosis. Our findings suggest a possible role for this non-apoptotic cell death in the prevention of neoplasia, and the activation of the non-apoptotic cell death program may become a potential cancer therapy complementing apoptosis-based therapies. In addition, the approach used in this study may be a valuable way to find genetically-regulated cell suicide programs that cannot be overcome by particular tumor types.
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PMID:Oncogenic Ras triggers cell suicide through the activation of a caspase-independent cell death program in human cancer cells. 1032 74


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