Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.6.1.44 (AGT)
 770 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mutations in the Kirsten ras 2 (K-ras) gene were described as early events in the process of colorectal carcinogenesis. The aim of this study was to find a possible relationship between the presence of K-ras mutation in samples of primary colorectal carcinomas and the clinico-pathological data of the investigated patients. Mutation in codon 12 of the K-ras gene was determined in 18 of 53 colorectal carcinomas (34%) in our group of patients. The presence of K-ras gene mutations was not related to gender, age of subject at diagnosis, staging or cancer location (p > 0.05). Sixteen of the 42 (38%) moderately differentiated carcinomas, and two of the eight (25%) well differentiated carcinomas contained K-ras mutation in codon 12, but none of the three poorly differentiated carcinomas contained the mutation. Moderately differentiated tumours contained an aspartate code GAT (in eight cases), a valine code GTT (in six cases), an alanine code GCT (in one case) and a serine code AGT (in one case) in codon 12. Well differentiated tumours contained only the valine code GTT (two cases). Our results show that the frequency of mutations in the K-ras gene in carcinomas in Central Europe is not different from the frequencies found in other parts of the world. The homogeneous incidence of K-ras mutation does not seem to be related to ethnic factors, dietary habits, or the composition of the diet.
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PMID:A relationship between K-ras gene mutations and some clinical and histologic variables in patients with primary colorectal carcinoma. 1051 Jul 29

It has been shown that the NF1 (neurofibromatosis type 1) gene encodes a tumor suppressor which inactivates ras proteins. Among malignant mesenchymal tumors, H-ras-1 mutations have been found in malignant fibrous histiocytoma, leiomyosarcoma and embryonal rhabdomyosarcoma. However, studies on H-ras-1 mutation of many cases of malignant peripheral nerve sheath tumors (MPNST) have not been documented. Therefore, we investigated H-ras-1 mutations of MPNST. In 45 cases of MPNSTs of our files, DNA was extracted from the formalin-fixed paraffin-embedded tissue, and the mutations of the H-ras-1 gene were detected by using PCR-RFLP (polymerase chain reaction- restriction fragment length polymorphisms) method and direct sequencing. We found two cases with H-ras-1 point mutation in MPNST for the first time. Both cases showed the same mutation in codon 13.1 [GGT(Gly) to AGT(Ser) transition]. Interestingly, both cases were associated with NF1. It is possibile that the mutation of the H-ras-1 gene occurred after the mutation of the NF1 gene in the MPNST.
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PMID:H-ras-1 point mutation in malignant peripheral nerve sheath tumors: polymerase chain reaction restriction fragment length polymorphism analysis and direct sequencing from paraffin-embedded tissues. 1081 8

Point mutations of c-K-ras in ovarian cancer were detected by replacement of GGT of codon 12 by GAT, AGT, TGT and GTT, polymerase chain reaction, agarose gel electrophoresis and Southern blot hybridization with a digoxigenin detection system. The incidence of four-typed point mutations of c-K-ras oncogene in 37 ovarian cancers was 35.1% (13/37) and the distributions were 32.4% (12/37), 2.7% (1/37), 0% and 0% of GGT to GAT, GGT to AGT, GGT to TGT, and GGT to GTT, respectively. The incidence of c-K-ras point mutations on codon 12 among 37 patients with ovarian cancer was 35.5% (8/22) in those with serous cystadenocarcinomas and 28.6% (2/7) in those with mucinous cystadenocarcinomas. c-K-ras point mutations on codon 12 were detected in 14.3% (1/7) of patients with stage I disease, 28.6% (2/7) with stage II disease, and in 43.5% (10/23) with stage III/IV disease, and there was a statistically significant increase in point mutations of c-K-ras oncogene with advancing clinical stage. The incidence of c-K-ras point mutations on codon 12 among 33 patients who had a pelvic lymph node dissection was 52.4% (11/21) in those with pelvic lymph node metastases and 16.7% (2/12) in those without pelvic lymph node metastases, a statistically significant difference. Furthermore, point mutation of c-K-ras gene was found most frequently in patients with advanced stage disease, and in those with pelvic lymph node metastases. Activation of c-K-ras oncogene seems to be a major factor in ovarian carcinogenesis and tumor progression.
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PMID:Detection of c-K-ras point mutation in ovarian cancer. 1157 63

ABSTRACTS: BACKGROUND: The carcinogenesis of colorectal cancer has been accepted by a model for a cascade of genetic alterations, named the adenoma-carcinoma sequence. In order to elucidate the carcinogenesis of the colorectal cancer more clearly, the genetic abnormalies of the non-neoplastic mucosal epithelium of the colon and rectum should be investigated. It has been speculated that colonic Paneth cell metaplasia (PaM) is one of the pre-neoplastic mucosa of colonic cancer. Therefore, we studied the propria mucosa of the right colon with PaM from the standpoints of the frequency of the K-ras codon 12 mutations (K-ras), which is initial genetic abnormality in colorectal cancer, and the loss of heterozygosity of microsatellite markers (LOH-MS), which has a relationship to development of colorectal cancer. METHODS: Fifty-two regions with PaM histopathologically from 12 surgically resected right colon specimens were studied. DNA extraction of the colonic mucosa with PaM was obtained using a microdissection method, and the frequency of the K-ras of PaM was investigated by enriched polymerase chain reaction-enzyme linked mini-sequence assay, and the frequency of the LOH-MS (D2S123, D17S250 and D5S346) of PaM was examined by high resolution fluorescenced labeled PCR primers. RESULTS: K-ras mutation was detected in fifteen regions among 52 PaM (28.9%). All mutations were a single mutation and GGT changed to AGT in eleven and GAT in four. LOH-MS were detected in twenty-one regions among 52 PaM (40.4%) (D2S123: 35.4%, 17/48 regions, D17S250: 13.7%, 7/51 regions, and D5S346: 0%, 0/52 regions). No K-ras mutations and LOH-MS were detected in the controls (Colorectal mucosa with no PaM). CONCLUSIONS: Colonic mucosa with Paneth cell metaplasia may be one of the pre-neoplastic mucosa in the development of the colonic epithelial neoplasia.
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PMID:Colonic Paneth cell metaplasia is pre-neoplastic condition of colonic cancer or not? 1570 98

HCV-associated hepatocellular carcinoma (HCC) is a common neoplasm in Egypt where genotype-4 is prevalent. In the present study the incidence and pattern of p53 mutations was assessed in relation to HCV-genotype- 4 in Egyptian HCC patients. We investigated 25 HCV positive HCCs for p53 mutations/overexpression in relation to HCV-NS3 by immunohistochemistry, SSCP and sequencing. Genotyping was done using LiPA-II and TRUGENE 5' NC' sequencing kit. Results were correlated to standard clinicopathologic prognostic factors for HCC. Thirteen cases showed p53 overexpression, and 10 showed p53 mutation (13 mutations) by sequencing (72% concordance). The highest mutation rate was in exons 6 and 7 (30%) followed by exons 5 and 8 (20%). Mutations included 3 transitions, 5 transversions, 3 deletions, and 2 insertions. All exon 7 mutations were at codon 249 specific for AFB1 (AGG-->AGT, Arg-->Ser) and codon 248 specific for vinyl chloride contamination (CGG-->TGG, Arg-->Trp). Other mutations reported are novel. Immunostaining for HCV NS3 was detected in 19 cases independent of p53 mutation. p53 aberrations were significantly associated with poor prognostic factors for HCC. However, no specific pattern for p53 mutations was observed in HCV genotype 4-associated HCC and no significant relation between p53 mutations, HCV-NS3 expressions or any HCV sub-genotype-4 sequence.
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PMID:p53 mutation in HCV-genotype-4 associated hepatocellular carcinoma in Egyptian patients. 1723 48

Patients with biliary tract carcinoma have a poor prognosis. Early detection efforts are urgently needed to ameliorate the dismal prognosis for these patients. Mutations of the KRAS2 gene are one of the most common genetic aberrations in this cancer. In this study, we used LigAmp, an ultrasensitive technology for detecting point mutations, to analyze KRAS2 mutations in patients with a variety of neoplastic and non-neoplastic pancreatobiliary diseases. DNA was isolated from 64 samples, including 44 bile samples and 20 serum samples. Oligonucleotides specific for KRAS2 G35A (GAT, G12D), G35T (GTT, G12V), and G34A (AGT, G12S) mutations were used. KRAS2 mutations were detected in 14 of 16 (87.5%) neoplastic bile samples and in 9 of 28 (32.1%) non-neoplastic bile samples. However, the mutation levels were significantly lower in the non-neoplastic bile (median = 0.4%) compared with those in the neoplastic bile (median = 5.1%). KRAS2 mutations were also detected in 9 of 11 (81.8%) serum samples from patients with biliary tract carcinoma, which was further confirmed by cloning BstN1-refractory PCR products and DNA sequencing. However, KRAS2 mutations were not present in the sera from eight patients with benign pancreatobiliary diseases. These data demonstrate that KRAS2 mutations are detectable in both bile and serum using LigAmp. This technology has the potential for early biliary tract carcinoma detection and possibly for residual disease monitoring post-therapy.
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PMID:Ultrasensitive detection of KRAS2 mutations in bile and serum from patients with biliary tract carcinoma using LigAmp technology. 1981 96

The DNA chip is a very powerful tool for genetic analysis. Conventional DNA chips that utilize fluorescence detection systems are very complicated, expensive and impractical, but the electrochemical array (ECA) chip is gaining popularity. To investigate the validity of the ECA chip, which utilizes ferrocenyl-naphthalene-diimide (FND), k-ras mutations in 20 pancreatic cancer tissues were examined. DNA was isolated from 20 pancreatic cancer tissues and subjected to a 2-stage polymerase chain reaction (PCR). The k-ras mutations were detected with the ECA chip. To verify the reliability of the ECA chip, the DNA was also analyzed by direct sequencing and the PCR-dependent preferential homoduplex formation assay (PCR-PHFA). The ECA chip could detect one mutation in a background of 1000 wild-type DNAs. K-ras mutations were identified in 17 out of 20 (85%) pancreatic cancer samples. Three mutations of codon 12 of k-ras, GTT, GAT and AGT, were detected. K-ras mutations were detected in 13 out of 20 (65%) samples by sequencing and in 17 out of 20 (85%) samples by PCR-PHFA. These findings were concordant with the ECA chip result. The FND-ECA chip is a sensitive, rapid and reliable method for screening point mutations in a variety of clinical samples.
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PMID:Rapid and Sensitive Assay of K-ras Mutations in Pancreatic Cancer by Electrochemical Detection with Ferrocenyl-naphthalene-diimide. 3139 41


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