Usefulness of Peptide Nucleic Acid (PNA)-Clamp Smart Amplification Process Version 2 (SmartAmp2) for Clinical Diagnosis of KRAS Codon 12 Mutations in Lung Adenocarcinoma Comparison of PNA-Clamp SmartAmp2 and PCR-Related Methods

KRAS is an oncogene that can be activated by Mutations. Patients with non-small cell lung cancer who have KRAS mutations do not respond to tyrosine kinase inhibitors; therefore, accurate detection of KRAS mutations is important for deciding therapeutic strategies. Although sequencing-related techniques have been frequently used, they are usually too complex, have low sensitivity, and are time-consuming for routine screening in clinical situations. We evaluated peptide nucleic acid (PNA)-clamp smart amplification process version 2 (SmartAmp2) as a detection method for KRAS codon 12 mutations in patient specimens compared with traditional sequencing and polymerase chain reaction-related methods. Among 172 lung adenocarcinoma samples, direct sequencing, enzyme-enriched sequencing, and PNA-enriched sequencing showed that 16 (9.3%), 26 (15.7%), and 28 (16.3%) tumors, respectively, contained KRAS Mutations in codon 12. Using PNA-clamp SmartAmp2, we could identify 31 (18.0%) tumors that had KRAS mutations in codon 12 within 60 minutes, three of which were undetected by polymerase chain reaction-related methods. On the other hand, we examined 30 nonmalignant peripheral lung tissue specimens and found no mutations in any of the samples using PNA-clamp SmartAmp2 In this study, we confirmed that PNA-clamp SmartAmp2 has high sensitivity and accuracy and is suitable for the clinical diagnosis of KRAS codon 12 Mutations. (J Mol Diagn 2010, 12:118-124; DOI: 10.2353/jmoldx.2010.090081)