Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.64 (proteinase K)
 4,071 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A newly modified non-RI, PCR-SSCP method is presented and applied to K-ras analysis of colorectal tumors. It comprises five steps: (1) sampling of tiny pieces of fresh solid tissue by scraping with disposable bamboo combs (thin bars made of bamboo, 3 x 3 x 120 mm in size); (2) one-step DNA extraction with lysis buffer containing proteinase K, Nonidet P-40 and Tween 20; (3) PCR with 108 bp, c-ki-ras 2 gene primers; (4) SSCP analysis with 10% formamide-added polyacrylamide gels; and (5) detection with silver staining. In comparison with conventional RI- or non-RI-PCR-SSCP, It can give reliable and clear results in a much shorter time (within a total of 6 h). This novel approach should allow more frequent use of molecular diagnosis in biopsies and surgical pathology.
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PMID:Simplified rapid non-radioactive PCR-SSCP method applied to K-ras mutation analysis. 891 53

The pathogenesis of carcinosarcoma is still a subject of controversy. In the present study, molecular techniques were applied to determine the pathogenesis of uterine carcinosarcomas. The patterns of chromosome X inactivation were analyzed, targeting a portion of exon 1 of the human androgen receptor (HUMARA) in malignant epithelial and mesenchymal components. The presence of p53 and K-ras mutations were also analyzed. H&E-stained sections of paraffin-embedded, formalin-fixed tissues were microdissected to obtain both epithelial and nonepithelial lesions from 25 carcinosarcomas, and DNAs were extracted by proteinase K digestion. Following treatment with methylation-sensitive restriction endonuclease (HhaI or HpaII), PCR amplification was performed using nested primers targeted to the HUMARA locus. Mutations in the p53 gene and K-ras gene were found in eight (32%) and six (24%) tumors, respectively. The patterns of chromosome X inactivation were different between the carcinomatous and sarcomatous components of three carcinosarcomas, indicating that these three tumors represent collision tumors. By contrast, the patterns of chromosome X inactivation, K-ras sequence, and p53 sequence were identical in both carcinomatous and sarcomatous components in 21 carcinosarcomas, indicating that these 21 tumors represent combination tumors. One case produced equivocal results that precluded determination of whether it represented a collision or combination tumor. These observations show that although most carcinosarcomas are combination tumors, some develop as collision tumors. The determination of histogenesis in individual cases of carcinosarcoma using molecular markers may be worthwhile, because the result could help predict the prognosis of individual cases and help guide clinical management.
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PMID:Molecular evidence that most but not all carcinosarcomas of the uterus are combination tumors. 939 63

To develop an objective reference for the cytological evaluation of atypical cells in bile and pancreatic juice, we analyzed K-ras oncogene mutation in atypical cell clusters, which were collected directly from cytological smear slides; 50 samples (cell clusters) from 31 smear slides of 21 patients with carcinomas of the pancreatic head region, and nine samples from eight cases of benign disease. These cell clusters (5-1000 cells/cluster) were selectively suspended in buffer containing proteinase K, and subjected to DNA extraction. K-ras codon 12 mutation was determined by polymerase chain reaction amplification, followed by digestion with BstNI. The K-ras gene was amplified in 20 of 21 cases with carcinoma (34/50 samples), and in seven of eight cases with non-neoplastic disease (8/9 samples). Among the cases of which primary tumors showed K-ras mutation, amplification was successful in 10 of 11 cases; mutation was demonstrated in three of seven cases with cytologically atypical cells (4/11 samples), and in three of three cases with cytologically malignant cells (5/7 samples). No mutation was identified in the 10 cases of carcinoma without K-ras mutation (0/15 samples), or in eight cases of non-neoplastic disease (0/8 samples). Cytological details could be comparatively evaluated between atypical cell clusters with or without mutation on the same smear slides in two cases. This type of direct analysis of atypical cell clusters may be useful in the self-assessment of cytological diagnosis of bile and pancreatic juice.
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PMID:Analysis of K-ras oncogene mutation directly applied to atypical cell clusters on cytologic smear slides of bile and pancreatic juice. 958 62

The role of serous borderline ovarian tumors (BOTs) in the pathogenesis of serous ovarian carcinomas is unclear. Some authors have compared mutations in serous BOTs to those in serous ovarian carcinomas, but the data on two common oncogenes, p53 and K-ras, remain inconclusive. To further clarify the relationship between the two tumors, we performed mutational analysis on tumors from a set of eight patients who first presented with advanced-stage serous BOTs and later developed grade 1 serous carcinomas. Epithelium from eight advanced-stage serous BOTs and subsequent grade 1 papillary serous carcinomas was microdissected and retrieved using a PixCell laser-capture microscope. Stroma was dissected as an internal control. The DNA was extracted with proteinase K and analyzed by single-strand conformational polymorphism-PCR for p53 and K-ras mutations. Bands with altered motility were analyzed by direct cycle sequencing. Seven of eight patients demonstrated different mutations in the secondary tumor compared with the primary tumor. For three patients, p53 mutations were identified in the BOTs that were absent from the carcinomas, suggesting a nonclonal origin for the carcinomas. These findings are consistent with the hypothesis that advanced-stage serous BOTs represent a distinct pathological entity compared with grade 1 serous epithelial ovarian carcinoma.
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PMID:Second primary or recurrence? Comparative patterns of p53 and K-ras mutations suggest that serous borderline ovarian tumors and subsequent serous carcinomas are unrelated tumors. 1158 64