Abstract
We have developed a sensitive and specific method for research studies, using Shifted Termination Assay (STA) to detect 12 possible KRAS mutations in codons 12 and 13. In this study, we analyzed 118 samples collected from formalin-fixed and paraffin-embedded (FFPE) metastatic colorectal cancer tumors.
The detection method includes carrying out a primer extension reaction in the presence of a wild-type DNA sequence. The primer extension reaction is stopped when encountered by a mutated base. If no mutation is detected the reaction terminates at the next nucleotide resulting in a large wild-type fragment. This creates a shift in the amount of labeled nucleotides incorporated on the primer extended product, and is then differentiated by fragment analysis using Applied Biosystems capillary electrophoresis systems.
Among the 118 samples tested, 32 were found to carry a mutation with 9 different variants. The most common mutations found in codon 12 were GGT>TGT (G12C, 9/32) and GGT>GTT (G12V, 8/32). Two rare variants in codon 12, GGT>GCT (G12A, 1/32) and GGT>CGT (G12A, 1/32), were also observed. For codon 13, the most common mutation found in the samples was GGC >GAC (G13D). In this study, we found 4 variants with 3 different types - 2 samples of GGC>AGC (G13S), 1 sample of GGC>GAC (G13D) and 1 sample of GGC>CGC (G13R). In summary, our data suggest that more KRAS mutations were observed in codon 13 relative to codon 12 in research samples, and the STA assay is an easy to use, robust method to detect possible KRAS mutations in codons 12 & 13. STA is currently for research use only, not for use in diagnostic procedures.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-222.
- ©2010 American Association for Cancer Research
Volume 70, Issue 8 Supplement
