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)

We prepared monoclonal antibodies specific for smg p21A, one of the low molecular weight GTP-binding proteins and possibly a suppressor molecule for ras p21. Two monoclonal antibodies (T22 and T212) reacted with smg p21A but not with Ki-ras p21, both of which were produced by Escherichia coli. These two clones detected an Mr 21,000 band in one-dimensional immunoblotting of extracts of a human pancreatic cancer cell line which was indistinguishable from a band detected by RASK-3, a monoclonal antibody specific for ras p21. However, T22 and T212 detected a single spot in two-dimensional immunoblotting that was clearly different from the three spots detected in the same cellular extracts by RASK-3. A series of normal and malignant human tissues were examined for the expression of smg p21A and ras p21 by immunohistochemical methods utilizing T22 and RASK-3. In essentially all tissues examined, both normal and malignant, smg p21A and ras p21 were expressed with great similarity. Expression of both molecules in all malignant tissues examined was coincident with that in normal tissues except that gastric cancer showed increased expression of the two molecules in comparison with normal gastric tissue.
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PMID:Similarity of expression of low molecular weight G proteins smg p21A and ras p21 in normal and malignant human tissues. 190 Dec 41

Alteration of oncogene and loss of chromosomal heterozygosity are infrequent in human gastric carcinoma compared with those in other gastrointestinal carcinomas. Amplification of c-erbB-2 gene is observed in well differentiated adenocarcinoma, while sam gene is found in poorly differentiated adenocarcinoma or scirrhous carcinoma. sam gene, which was isolated from a gastric cancer cell line KATO-III by a DNA renaturation method, encodes tyrosine-specific protein kinase domain. A good correlation evidently exists between the synchronous expression of TGF alpha and ras p21 and biological malignancy of gastric carcinoma. c-myc and c-fos proteins are found not only in tumor cells but also in stromal cells including macrophages and fibroblast around the tumors. The prognosis of patients with c-myc p 62-positive stromal cells is significantly better than that of patient with p 62-negative stromal cells. Coamplification of the hst-1 gene and int-2 is observed in 50% of primary tumors and all metastatic tumors of esophageal carcinoma. PCR (polymerase chain reaction) technique seems to be useful for the detection of oncogene point mutation in human gastric carcinoma.
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PMID:[Oncogenes in human gastric carcinoma]. 254 46

The expression of the ras gene product p21 in normal gastric mucosa, early gastric carcinoma of diffuse (gastric) and intestinal types, and in adjacent mucosal abnormalities is reported. The analysis was performed on paraffin sections by an immunohistochemical assay using the mouse monoclonal antibody RAP-5 and the rat monoclonal antibody Y13-259. Expression of ras p21 was assessed by staining intensity and percentage of positively stained cells. In comparison to normal gastric mucosa of non-cancer patients, p21 was overexpressed in nearly all early carcinomas of both types and in the dysplastic and/or metaplastic mucosal alterations accompanying intestinal type of gastric cancer. Increased p21 expression was also observed in the normal-appearing mucosa adjacent to early carcinomas of diffuse type, but not in the morphologically normal gastric epithelium adjacent to the intestinal type. The results of this investigation suggest that ras p21 overexpression may be related to early events of human gastric carcinogenesis. The study supports the notion of different pathways in the development of diffuse (gastric) and intestinal types of gastric carcinomas.
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PMID:Expression of ras oncogene p21 protein in early gastric carcinoma and adjacent gastric epithelia. 255 Jan 23

Sixteen clones (RASK-1 to -16) of murine monoclonal antibodies were raised against ras Mr 21,000 protein (p21). The p21 produced by Escherichia coli with inserted v-Ki-ras genes was used as immunogen. RASK-1 was found to be specific for Ki-ras p21, whereas RASK-2 to -16 reacted with the p21s of Ki-, N-, and Ha-ras genes in both enzyme-linked immunosorbent and immunoblotting assays. Binding inhibition assays with biotinylated monoclonal antibodies by enzyme-linked immunosorbent assay showed that the monoclonal antibodies of the 16 clones included those binding to several mutually distinct sites on p21. The expressions of ras p21 in human stomach and thyroid tissues were examined with RASK-3, which reacted with all the Ki-, N-, and Ha-ras p21s immunohistochemically by the avidin-biotin peroxidase complex method. Formalin-fixed, paraffin-embedded tissues of 101 cases of stomach cancer, 53 cases of noncancerous stomach, 74 cases of cancer of the thyroid, and 59 cases of noncancerous thyroid were analyzed. In both the stomach and thyroid, cancer cells expressed p21 predominantly. Cells of cases with various noncancerous disorders as well as certain types of normal cells were also p21 positive. These findings suggest that precaution is required in use of p21 as a cancer marker. Expression of p21 was noted in moderately to well-differentiated stomach cancer, intestinal metaplasia, and atypical hyperplasia. This finding suggests that the appearance of p21 in stomach cancer may be initiated before cytological transformation.
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PMID:Preparation of anti-ras Mr 21,000 protein monoclonal antibodies and immunohistochemical analyses on expression of ras genes in human stomach and thyroid cancers. 304 40

Using anti-ras p21 monoclonal antibodies, RASK-3, which reacts with all of Ki-, N-, and Ha-ras p21, we examined by immunohistochemistry the expression of p21 in human gastric cancer (80 cases) and benign gastric lesions (32 cases). Ten percent formalin fixed tissues were studied. Ras p21 was positive in 51 cases (64%) out of 80 cases and partially positive in 12 cases (15%) at the cancerous areas. Ras p21 was partially positive in 7 cases (9%) at the noncancer areas of the same slides. Intestinal metaplasia and normal parietal cells were also often positive. In the study of 32 cases of benign stomach lesions, 2 out of 3 cases of atypical hyperplasia (ATP) and 3 out of 11 cases of stomach ulcer with regenerating epithelials were positive. Ras p21 was more dominantly expressed in the well-differentiated type of stomach cancer than the poorly differentiated type. Expression of ras p21, however, was not correlated either with the grades of cancer invasion or with the types of cancer infiltration.
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PMID:Analysis of ras gene expression in stomach cancer by anti-ras p21 monoclonal antibodies. 305 35

Monoclonal antibodies reactive with ras gene products were produced. Specificity of the antibodies obtained was determined by ELISA and immunoblotting assays. Using one of those anti-ras p21 monoclonal antibodies, RASK-3 the expression of p21 in human stomach cancer and thyroid cancer was studied by means of immuno-histochemistry. ras p21 was more dominantly expressed in cancer cells than in normal epithelial cells.
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PMID:[Oncogene products as tumor markers]. 330 May 59

Gastric cancer involves changes in multiple oncogenes and multiple suppressor genes, and it causes genetic instability. Aberrant expression and amplification of the c-met gene, inactivation of the p53 gene, and CD44 abnormal transcripts are common events of both well differentiated and poorly differentiated gastric cancers. Amplification of the cyclin E gene is also observed in gastric cancer regardless of histologic type. Decreased expression of the pic1 (p21) gene occurs independent of the p53 mutations. In addition, K-ras mutations, c-erbB-2 gene amplification, loss of heterozygosity (LOH) and mutations of the APC gene, LOH of the bcl-2 gene, and LOH at the DCC locus are preferentially associated with well differentiated gastric cancer. Moreover, LOH on chromosome 1q is involved in the progression of well differentiated cancer. Precancerous lesions, including hyperplastic polyp, intestinal metaplasia, and adenoma, share genetic changes found in well differentiated cancers. Conversely, genetic instability may be involved in the first step of stomach carcinogenesis of the poorly differentiated type. Reduction or loss of cadherin and catenins, K-sam gene amplification, and c-met gene amplification are necessary for the development and progression of poorly differentiated or scirrhous carcinoma. Interaction between cell-adhesion molecules in the c-met expressed tumor cells and hepatocyte growth factor from stromal cells is implicated in the morphogenesis of two types of gastric cancer.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Molecular biology of gastric cancer. 767 88

The expression of integrin Alpha-6-subunit, laminin, type IV collagenase, type IV collagen and ras p21 were studied immunohistochemically in gastric cancer. The results showed that the expression of alpha 6 and laminin (LN) was often in continuous or interrupted linear pattern in the expanding type of gastric carcinoma (GC); while in the infiltrating type of GC, they were expressed either in interrupted spotty or fragmentary pattern, or almost lost. Suggesting that the interaction between the laminin receptor and its ligand may influence the mode of growth in GC. Intense expression of type IV collagenase was often found in GC cells, especially in the infiltrative type of GC and in those with lymph node metastasis, it can therefore be used as a marker for invasion and metastasis of GC cells. A positive correlation was found between the expression of type IV collagenase and ras p21 in GC. The expression of type IV collagen was similar to that of laminin, but in reverse proportion to the expression of type IV collagenase. These investigations provide a better understanding of the molecular pathological basis of tumor invasion and metastasis.
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PMID:[The relation between integrin, type IV collagenase and extracellular matrix in invasion and metastasis of gastric carcinoma]. 787 59

Recent epidemiological observations have indicated that the role of Helicobacter pylori (HP) infection in the pathogenesis of gastric cancer is an important but unresolved issue. We used the polymerase chain reaction, a sensitive and specific assay, to detect the HP infection in gastric biopsy specimens and examined the correlations between HP infection and point mutation at 12 codon of H-ras oncogene, overexpression of ras p21 and DNA content. The results showed that the mutation rate of H-ras oncogene is higher in the group with HP infection than in those without HP infection. Furthermore, there is strong evidence that HP infection is associated with the increased expression of ras p21 protein, which suggested that HP infection increased the risk of ras oncogene activation. It is also noted that a significant relationship between infection with HP and the increase of DNA content and s% phase cells, indicated that rapid turnover of cells resulting from infection injury increases the risk of DNA damage.
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PMID:Study on the association between Helicobacter pylori infection and the pathogenesis of gastric cancer by using molecular biological techniques. 796 16

A case with primary triple cancers including thyroid cancer is reported. A 57-year old woman complaining of laryngeal discomfort was found to have an firm elastic lump on the right anterior neck. On 123I scan, the nodule in the right thyroid lobe accumulated considerable amounts of radioiodine as a warm nodule, while the remainder of the gland showed decreased uptake. Thyroid hormone levels remained within normal ranges. Cytological findings obtained by fine-needle aspiration biopsy showed papillary carcinoma. Right lobectomy was performed. The histological examinations revealed papillary carcinoma embedded within adenomatous thyroid tissue. It is probable that the surrounding adenomatous tissue accumulated radioiodine, since the warm nodule on 123I scan was larger than the size of the carcinoma. Examinations of the gastrointestinal tract revealed the presence of poorly differentiated adenocarcinoma in the stomach and well differentiated adenocarcinoma (carcinoma in adenoma) in the rectum. Expressions of ras p21 and p53 were examined immunohistochemically in these carcinoma tissues. The ras p21 product was clearly detected in not only the thyroid carcinoma but in a part of the surrounding adenomatous regions as well. Both ras p21 and p53 proteins were observed in the rectal cancer tissue. In contrast, these oncoproteins were not found in the gastric cancer tissue. In this case ras oncogene activation may be an early event in the tumorigenic process of the thyroid and rectum. However, different genetic alterations seem to occur during the development of these three carcinomas.
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PMID:[A case report of primary triple cancers in the thyroid, stomach and rectum with evidence of variable oncoprotein expressions]. 800 92


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