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

The investigation of molecular evidence of gastric carcinoma will be contributable to the prevention, gene diagnosis and therapy of human gastric neoplasms. To determine the specific genetic change in human gastric cancer (HGC) and precancerous lesions, we analysized FISH, PCR/SSCP, IHC and DNA sequencing by using multiple probes to detect the gene abnormalities (mutation, deletion, amplification or overexpression of genes) of 67 fresh tumors, 63 endoscopic biopsies including 30 dysplasia (DYS) and 33 intestinal metaplasia (IM, and 4 tumor cell lines from HGC patients. Multiple genetic abnormalities including hypomethylation of H-ras gene, amplification and overexpression of met and erbB2, deletion of APC, mts1/p16, p53 and nm23 gene and point mutation of p53 gene were noted in HGC and precancerous lesion of human gastric mucosa. Among these changes, p53 gene was the highest frequence genetic alteration in 39/67 (54-58%) of gastric carcinoma. These results indicate that overexpression of met and H-ras occurs at early stage in progression of neoplasia, amplification of met, erbB2 and akt2 gene occurs at progressing stage of tumorigenesis, deletion of p53, APC, mts1/p16 and nm23 occurs at advanced stage in the progression of cancer. The abnormalities should be associated with malignant phenotypes: poor differentiation, vascular invasion, lymph nodes metastasis, and low survival time. We detected p53 gene mutation in both cancer and precancerous lesions of IM and DYS. These results suggest that p53 may be a susceptible gene and alteration of p53 gene plays an important role in the development of HGC.
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PMID:[Multiple gene alterations involved in the processor of human gastric carcinogenesis]. 869 90

In order to detect loss of heterozygosity (LOH) at APC and MCC genetic loci in gastric carcinoma, the authors established a micro-wax-mediated hot start PCR technique. This method allowed a specific gene amplification, and it was useful especially in the amplification of formalin-fixed or stained tissues. In 44 cases of gastric cancer, 29 cases were informative of the APC locus. LOH was found in 8 cases (27.6%): 2 cases in 2 moderately well-differentiated cancer, 2 cases in 13 differentiated cancer, and 4 cases in poorly-differentiated cancer. One of the 3 cases of gastric cancer at early stage also showed LOH. LOH at MCC locus was detected in only 2 of the 25 (8.0%) gastric cancer patients informative. These data suggest that abnormality of APC gene plays a role in the tumorigenesis of gastric cancer and the change may occur at the early stage of tumor development.
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PMID:[Relation between loss of heterozygosity at APC and MCC genetic loci and biological behaviour of gastric carcinoma]. 873

Germline mutations of the adenomatous polyposis coli gene are associated with the dominantly inherited syndrome of familial adenomatous polyposis. Somatic mutations in this gene are an early event in sporadic colorectal tumorigenesis. Here we report a family with genetic characteristics that do not conform exactly to either of these situations. The index case and three siblings presented with colorectal cancer, and another sibling had lung cancer. There was no evidence of colorectal cancer susceptibility in previous generations, although one case of gastric cancer was observed. Using restriction fragment length polymorphism, single-strand conformational polymorphism, and sequencing analysis, we screened each living family member for alterations in the mutation cluster region of exon 15 of the APC gene. A constitutional single base pair substitution at codon 1317 was observed in two of the siblings with colorectal cancer, but neither exhibited any colonic features typical of FAP nor an early onset of cancer. This constitutional change is a missense mutation and therefore does not result in the truncation of the APC protein, the most commonly observed result of mutation in this gene. We present evidence that this change is not a polymorphism and may be capable of conferring a growth advantage. This particular germline APC mutation does not completely cosegregate with cancer in this family; therefore, we conclude that another gene locus may be responsible for the increased cancer risk observed.
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PMID:Germline APC mutation (Gln1317) in a cancer-prone family that does not result in familial adenomatous polyposis. 883 76

Mycoplasmas are tiny polymorphic prokaryotic organisms (0.2-0.3 microm) that lack a cell wall and reside ubiquitously at the cell membrane or internalized into the cell. The organisms have been implicated in many diseases including functioning as cofactors catalyzing the HIV disease state. The oncogenic potential of mycoplasmas was only recently realized when they were shown to cause chromosomal changes and in vitro cell transformations through gradual progressive chromosomal loss and translocations. While a recent study linked mycoplasmas with gastric cancer, the association between mycoplasmas and ovarian cancer has not been established. Recently, a commercial assay which combined polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) methods was developed for the detection of mycoplasmas. The present objective was to determine the prevalence of mycoplasmas in archived paraffin-embedded malignant ovarian cancer tissue. The combined PCR-ELISA procedure was used with consensus primers targeting for 15 species of mycoplasmas and acholeplasmas. Archived human malignant ovarian cancer tissues (N = 27 cases) embedded in paraffin blocks were processed, and DNA was extracted and the presence of DNA verified. The extracted DNA specimens were randomly divided into three groups for analyses. PCR-ELISA assays were performed on extracted DNA together with appropriate negative and positive controls. The results showed mycoplasmas were present in 59.3% of the malignant ovarian cancer specimens. PCR-ELISA analysis of Neisseria gonorrhea and Chlamydia trachomatis controls did not produce cross-reacting false-positive results. The results suggest an association between mycoplasmas and malignant ovarian cancer. A 59.3% prevalence rate was demonstrated for mycoplasmas in paraffin-embedded ovarian cancer tissues. The mechanism involved in oncogenesis by mycoplasmas remains to be elucidated.
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PMID:Prevalence of mycoplasma conserved DNA in malignant ovarian cancer detected using sensitive PCR-ELISA. 891 Jun 37

Formalin-fixed and paraffin-embedded tissues are a valuable resource for diagnosis and research. PCR is one of the most powerful methods of retrospective analysis of the DNA present in fixed tissues. One major problem with the molecular analysis of tissue samples, however, is cellular heterogeneity, ie, the large variety of cell types usually present in these specimens can mask cell-specific genetic alterations associated with disease. Herein we describe a procedure for obtaining and analyzing single cells recovered from stained histologic tissue sections without risking contamination from neighboring cells. An ultraviolet laser microbeam was used to physically destroy the tissue surrounding the single cells of interest. These cells, now freed from adjacent cells, were then easily retrieved with a motorized, computer-controlled micromanipulator and molecularly characterized through the use of PCR-based microanalysis. This accurate microdissection technique, followed by DNA amplification and direct sequencing, revealed a novel mutation in the gene coding for the cell adhesion molecule E-cadherin in single tumor cells that was absent in the adjacent single epithelial cells of a patient with early gastric cancer of the diffuse type. In this form of malignancy, tumor cells lose homophilic cell-to-cell interactions and invade the connective tissue as single cells. E-cadherin gene mutations have previously been detected in advanced diffuse-type gastric cancer and gastric carcinoma cell lines. The present study suggests that E-cadherin gene mutations may be an early event in gastric tumorigenesis. The laser-based isolation and subsequent molecular characterization of individual cells, as described herein, allows for micrometer-sized precision and should prove useful in detecting the nucleic acid abnormalities that underlie cancer, infection, and genetic disease.
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PMID:Single-cell mutation analysis of tumors from stained histologic slides. 897 75

The status of genetic instability was determined with seven microsatellite markers from 40 patients with primary gastric adenocarcinoma. For those cases with microsatellite instability, alterations of hMSH2 were further investigated by direct sequencing of reverse transcription-polymerase chain reaction products. Twelve (30%) of 40 patients were found to have microsatellite instability. Among them, one patient (1/6, 16.7%) was early gastric cancer and 11 (11/34, 32.4%) were advanced gastric cancer. There were seven patients with diffuse type (7/18, 38.7%), while five (5/22, 22.7%) were intestinal type tumors. The entire coding region of the hMSH2 gene in these 12 affected individuals was amplified and sequenced. Only a 41-year-old female patient with diffuse type advanced gastric cancer showed a GCT to TCT missense mutation at codon 207 with predicted protein change from alanine to serine. Our results indicate that genetic instability plays an important role in gastric tumorigenesis and alterations of the hMSH2 gene are related to only a small portion of sporadic gastric adenocarcinoma with microsatellite instability.
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PMID:Infrequent hMSH2 mutations in sporadic gastric adenocarcinoma with microsatellite instability. 906 23

Microsatellite instability (or replication error phenotyp) is a new molecular phenotyp of a substantial fraction of human cancers. The microsatellite instability in these cancers arises from alterations in normal regions of the genome consisting short sequences of repeated DNA. Ubiquitous changes in length of microsatellite sequences between constitutional and tumor DNA occur in about 90% of cases of HNPCC and in about 15% of cases of non-familial, sporadic colorectal cancer. Microsatellite instability is also found in a substantial percentage of sporadic endometrial, and gastric cancer, as well as in additional sporadic cancers, such as lung cancer which is usually not associated with HNPCC. Thus far, four different mismatch repair genes (hPMS1, hPMS2, hMLH1 hMSH2), all homologous to bacterial DNA repair genes have been identified as involved in HNPCC kindreds, and consequently they are associated with microsatellite instability. In conclusion, these basic genetic informations provide new insights into a new molecular pathway in oncogenesis, i.e. the occurrence of mutations in genomic stability genes leading to an increased cellular mutation rate (replication error phenotyp) and thus to cancer.
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PMID:[Microsatellite instability--a new aspects in genetics and molecular biology of hereditary nonpolyposis and sporadic colorectal tumors]. 908 61

p16 (MTS-1, multiple tumor suppressor gene 1), a putative tumor suppressor gene, is one of the cyclin-dependent kinase inhibitors (CDI) and it regulates the G1/S transition of the cell cycle. To clarify the role of p16 in primary gastric cancer, we have investigated somatic mutations of this gene by using the polymerase chain reaction/single strand conformation polymorphism (PCR-SSCP) method. In 23 surgical specimens of primary gastric cancer, none were detected in exon1 and exon 2. Among the 6 human gastric cancer cell lines examined, PCR products were not found in 2, MKN28 and MKN45, suggesting the presence of homozygous deletions. No mutation was found in the other 4 cell lines. Furthermore, decreased expression levels were not observed in 13 gastric cancer tissues by reverse transcription PCR (RT-PCR). Considering the above results of PCR-SSCP and RT-PCR, genetic alterations of the p16 gene are rarely implicated in human gastric cancer tumorigenesis.
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PMID:Infrequent alterations of the p16 (MTS-1) gene in human gastric cancer. 922 7

Although it has been demonstrated that acromegalic patients have an increased risk of neoplasms, especially colon neoplasms, gastric cancer with acromegaly is very rare--only five cases have been reported to date in Japan. We report here a rare case of gastric cancer with acromegaly in a 58-year-old woman, whose acromegalic change began at age 44. This patient showed typical clinical features of acromegaly, with increased concentrations of blood growth hormone (GH) and insulin-like growth factor I (IGF-I); she had four types of neoplasms; gastric cancer, colon tubular adenoma with moderate atypia, pancreatic mucinous cystadenoma, and subcutaneous lipoma. The gastric cancer was macroscopically 0-IIc type, 3.0 x 2.5 cm in size, and histologically diagnosed as a poorly differentiated adenocarcinoma with limited invasion of the mucosal layer. The previously documented stimulatory effects of GH and/or IGF-I on tumorigenesis and cell proliferation may have been responsible for the development of the multiple neoplasms in our patient.
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PMID:A rare case of gastric cancer in an acromegalic patient. 925 Sep 2

We analyzed p15 and p16 gene alterations in gastric cancer. Only MKN45 showed both homozygous deletions but other cell lines and all of tumor specimens did not show any alterations. Using RT-PCR analysis, decreased or no expression of the p16 gene was found in 1 of 7 cell lines (except MKN45) (14.2%) and in 8 of 20 tumors (40%), whereas no abnormalities of p15 gene expression were found. These results suggest that the p16 gene may correlate with tumorigenesis and tumor expansion due to decrease or loss of gene products in gastric cancer.
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PMID:[Alteration of p15 and p16 gene in gastric cancer]. 926 16


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