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Updated: Apr 29, 2026
Single Droplet Digital Polymerase Chain Reaction for Comprehensive and Simultaneous Detection of Mutations in Hotspot Regions
Published on: September 25, 2018
Detection of KRAS codon 12 and 13 mutations by mutant-enriched PCR assay
Ya-Sian Chang1, Tze-Kiong Er2, Hsiu-Chin Lu3
1Epigenome Research Center, China Medical University Hospital, Taichung, Taiwan; Department of Laboratory Medicine, China Medical University Hospital, Taichung, Taiwan.
Background:
The identification of KRAS mutations before the administration of anti-epidermal growth factor receptor (EGFR) therapy of metastatic colorectal cancer (mCRC) has become important. The aim of the present study was to develop a novel technology that can increase detection sensitivity for KRAS mutations.
Methods:
DNAs were extracted from colorectal cancer tissues and formalin-fixed, paraffin-embedded (FFPE) colorectal cancer samples. Mutant-enriched PCR assay utilizes the exceptionally thermostable endonucleases, PspGI for codon 12 and PhoI for codon 13, for specific amplifying KRAS mutations from mixed samples. The amplified PCR products were subjected to single-base primer extension or sequencing. Digital PCR was used to evaluate some of the results.
Results:
We compared the results with that from direct sequencing. In the FFPE samples, thirteen discordant samples were found. We showed that the mutant-enriched PCR assay can identify the codons 12 and 13 mutation in a mixed population of mutant and wild type DNA sequences at 1:1000 and 1:400, respectively. The sensitivity of this method is lower than the digital PCR.
Conclusions:
We developed a rapid and highly sensitive method to detect codons 12 and 13 mutations of the KRAS gene. This method is a powerful tool for finding low-abundance variations in genomic DNA.
