K-ras mutation detection in colorectal cancer using the Pyrosequencing technique.

Abstract

The identification of gene mutations is a critical goal for the assessment of diagnosis and prognosis in cancer disease, particularly by direct sequencing. Pyrosequencing is a straightforward, non-electrophoretic DNA sequencing method using the luciferase-luciferin light release as a signal for nucleotide incorporation into a PCR template DNA. In this study, we aimed to investigate mutations in the K-ras gene using Pyrosequencing technology, because its reliable chemistry and robust detection mechanism allow for rapid, real-time detection of sequencing events. For the simultaneous detection of the predominant K-ras codons 12 and 13 mutations, we established a sequencing protocol based on the design of a single PCR primer pair and a single sequencing primer. The assay has been validated with DNA from 65 colorectal carcinomas. Furthermore, analysis of the rare K-ras codon 61 mutation was included. In 29% (19/65) of the patients, the K-ras gene was found to be mutated, whereas codons 12 and 13 were most frequently affected (18/65, 27.7%). Mutations with the highest frequency were G-->A transitions (12/19, 63%), followed by G-->T transversions (5/19, 26%). Overall survival was significantly shorter in patients with a tumor containing K-ras codon 12 mutations than in those without K-ras codon 12 mutations (p=0.024). In conclusion, we found Pyrosequencing to be a suitable technology for fast detection of hot-spot mutations in the K-ras oncogene. We demonstrated an important relationship between K-ras codon 12 mutations and overall survival in colorectal cancer patients.

• Authors: Angela Poehlmann, Doerthe Kuester, Frank Meyer, Hans Lippert, Albert Roessner, Regine Schneider-Stock
• Journal: Pathology, research and practice (Pathol Res Pract) Vol. 203 Issue 7 Pg. 489-97 ( 2007) ISSN: 0344-0338 [Print] Germany
• PMID: 17629419 (Publication Type: Journal Article)

Chemical References

• DNA Primers
• DNA, Neoplasm

Topics

• Adenocarcinoma (genetics, mortality)
• Base Sequence
• Colorectal Neoplasms (genetics, mortality)
• Cytogenetic Analysis (methods)
• DNA Mutational Analysis (methods)
• DNA Primers
• DNA, Neoplasm (genetics)
• Genes, ras
• Humans
• Kaplan-Meier Estimate
• Molecular Sequence Data
• Mutation
• Reverse Transcriptase Polymerase Chain Reaction
• Sensitivity and Specificity