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)

The aim of this study was to identify K-ras mutations as marker for isolated tumor cells in liver, lymph node, and bone marrow specimens of colorectal cancer patients. To detect these, a PCR-RFLP assay was used with a sensitivity exceeding that of routine histopathology by at least 1 order of magnitude. In addition, the ratio of mutated versus wild-type alleles was determined by an internal standard. Of 199 patients, 74 (37.5%) were found to bear a K-ras-positive tumor. Of these, 60 (81%) were mutated in codon 12 and 14 (19%) in codon 13 (P < 0.001). In addition, 14 organs were found K-ras positive, 13 of which were from 12 patients with a K-ras-positive tumor (16%) and 1 from a patient with a K-ras-negative tumor (0.8%). Eight patients exhibited liver involvement and 6 showed lymph node involvement. Remarkably, no bone marrow specimen was found K-ras positive (P < 0.017 versus liver involvement). Sequence analysis of tumor DNA revealed that GGT (Gly) was replaced by GAT (Asp; 35%), GTT (Val; 32%), AGT (Ser; 13%), GCT (Ala; 10%), TGT (Cys; 8%), and CGT (Arg; 2%) for codon 12, and by GAC (Asp) as the only type of mutation for codon 13. In colorectal carcinomas the ratio of K-ras mutated versus wild-type alleles ranged over 4 orders of magnitude (10(0)-10(-4), median: 10(-2)) and was correlated with both, residual tumor load (R1/2; P = 0.028) and distant metastasis (M1; P = 0.057). These results show that detection of K-ras mutated alleles by PCR-RFLP in patients with colorectal carcinoma may aid in the identification of isolated tumor cells. High ratios of K-ras alleles were correlated with certain negative prognostic parameters (R,M). In accord with its function as a primary filter for colorectal carcinoma cells, the liver was more often contaminated with K-ras-positive cells than bone marrow.
 ...
PMID:Detection of isolated tumor cells by polymerase chain reaction-restriction fragment length polymorphism for K-ras mutations in tissue samples of 199 colorectal cancer patients. 1476 87

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.
 ...
PMID:Ultrasensitive detection of KRAS2 mutations in bile and serum from patients with biliary tract carcinoma using LigAmp technology. 1981 96