Comparison of a PNA Clamp PCR and an ARMS/Scorpion PCR Assay for the Detection of K-ras MutationsNordgård, Oddmund PhD*,†; Oltedal, Satu Msc†; Janssen, Emiel A. M. PhD‡; Gilje, Bjørnar MD*; Kørner, Hartwig MD, PhD§,∥; Tjensvoll, Kjersti PhD*,†; Smaaland, Rune MD, PhD*,†,¶Author Information Departments of *Hematology and Oncology †Laboratory for Molecular Biology ‡Pathology §Surgery, Stavanger University Hospital, Stavanger ∥Department of Surgical Sciences ¶Institute of Medicine, University of Bergen, Bergen, Norway Supported by the Western Norway Regional Health Authorities, the Norwegian Cancer Society, the Folke Hermansen Fund, and Stavanger University Hospital. Reprints: Oddmund Nordgård, PhD, Laboratory for Molecular Biology, Stavanger University Hospital, P.O. Box 8100, 4068 Stavanger, Norway (e-mail: firstname.lastname@example.org). Diagnostic Molecular Pathology: March 2012 - Volume 21 - Issue 1 - p 9–13 doi: 10.1097/PDM.0b013e31821e59dc Buy Metrics Abstract Point mutations in the K-ras gene have been shown to confer resistance against epidermal growth factor receptor-directed therapy of metastatic colorectal cancer. Accordingly, K-ras mutation testing has become mandatory in hospitals offering such treatment. We compared the performance and reagent costs of 2 sensitive methods for detection of K-ras mutations: a peptide nucleic acid (PNA) clamp polymerase chain reaction (PCR) assay and a commercially available amplification refractory mutation system/Scorpion (ARMS/S) PCR assay. Both methods were applied in parallel to 101 formalin-fixed, paraffin-embedded tumor and metastasis samples from patients with colon cancer. The PNA clamp PCR assay detected K-ras mutations in 35% (35 of 101) of the samples, whereas the ARMS/S PCR assay detected mutations in 27% (27 of 101) of them. There was 92% (93 of 101) concordance between the 2 methods and the κ coefficient for the comparison was 0.82. The 8 discordant cases were exclusively positive by PNA clamp PCR. Finally, the reagent costs of the PNA clamp PCR assay were estimated to be at least 20 times lower than the ARMS/S assay. We concluded that the high performance and low costs associated with the PNA clamp PCR assay encourage its use in the administration of personalized epidermal growth factor receptor-directed therapy. © 2012 Lippincott Williams & Wilkins, Inc.