Feasibility and robustness of amplification refractory mutation system (ARMS)-based KRAS testing using clinically available formalin-fixed, paraffin-embedded samples of colorectal cancers

Jpn J Clin Oncol. 2011 Jan;41(1):52-6. doi: 10.1093/jjco/hyq151. Epub 2010 Aug 9.

Abstract

Background: KRAS mutation testing is recommended for the discernment of metastatic colorectal cancer patients who are unlikely to benefit from anti-epidermal growth factor receptor antibodies. A recently developed amplification refractory mutation-Scorpion system is becoming a standard method for KRAS mutant detection. The feasibility and robustness of this system using DNA samples from clinically available formalin-fixed, paraffin-embedded specimens were evaluated.

Methods: Genomic DNA from macro-dissected 110 specimens was applied for the KRAS mutant detection using a commercial amplification refractory mutation-Scorpion system kit. Success rate and mutant detection rate of the test were evaluated.

Results: Small intra- and inter-lot deviations of the testing kit and a good concordance among different real-time polymerase chain reaction systems suggested the reliability of the amplification refractory mutation-Scorpion system. Though one-third of the 110 samples that were tested did not contain a sufficient amount of DNA to detect a 1% concentration of mutant alleles, the mutant detection rate was not impaired using tumor DNA concentrated by macro-dissection. Using a higher amount of template DNA, which supposedly contained abundant interfering substances, prevented the detection of the exogenous control amplicons, resulting in a reduced success rate. Adjusting the template amount according to the total DNA concentration might reduce the failure rate.

Conclusion: The amplification refractory mutation-Scorpion system with formalin-fixed, paraffin-embedded specimen-derived DNA samples exhibited an acceptable feasibility and robustness suitable for routine clinical practice.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Colorectal Neoplasms / genetics*
  • Feasibility Studies
  • Fixatives
  • Formaldehyde
  • Gene Amplification
  • Humans
  • Mutation*
  • Paraffin Embedding
  • Polymerase Chain Reaction
  • Predictive Value of Tests
  • Proto-Oncogene Proteins / genetics*
  • Proto-Oncogene Proteins p21(ras)
  • ras Proteins / genetics*

Substances

  • Fixatives
  • KRAS protein, human
  • Proto-Oncogene Proteins
  • Formaldehyde
  • Proto-Oncogene Proteins p21(ras)
  • ras Proteins