title: A comparison of four methods for detectingKRASmutations in formalin-fixed specimens from metastatic colorectal cancer patients.
abstract: There is currently no standard method for the detection of Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation status in colorectal tumors. In the present study, we compared theKRASmutation detection ability of four methods: direct sequencing, Scorpion-ARMS assaying, pyrosequencing and multi-analyte profiling (Luminex xMAP). We evaluated 73 cases of metastatic colorectal cancer (mCRC) resistant to irinotecan, oxaliplatin and fluoropyrimidine that were enrolled in an all-case study of cetuximab. TheKRASmutation detection capacity of the four analytical methods was compared using DNA samples extracted from tumor tissue, and the detection success rate and concordance of the detection results were evaluated.KRASmutations were detected by direct sequencing, Scorpion-ARMS assays, pyrosequencing and Luminex xMAP at success rates of 93.2%, 97.3%, 95.9% and 94.5%, respectively. The concordance rates of the detection results by Scorpion-ARMS, pyrosequencing and Luminex xMAP with those of direct sequencing were 0.897, 0.923 and 0.900 (κ statistics), respectively. The direct sequencing method could not determineKRASmutation status in five DNA samples. Of these, Scorpion-ARMS, pyrosequencing and Luminex xMAP successfully detected three, two and oneKRASmutation statuses, respectively. Three cases demonstrated inconsistent results, whereby Luminex xMAP detected mutatedKRASin two samples while wild-typeKRASwas detected by the other methods. In the remaining case, direct sequencing detected wild-typeKRAS, which was identified as mutatedKRASby the other methods. In conclusion, we confirmed that Scorpion-ARMS, pyrosequencing and Luminex xMAP were equally reliable in detectingKRASmutation status in mCRC. However, in rare cases, theKRASstatus was differentially diagnosed using these methods.
authors.affiliation: Multidisciplinary Treatment Cancer Center, Kurume University Hospital, Kurume, Fukuoka 830-0011, Japan.
authors.forename: Mototsugu
authors.initials: M
authors.lastname: Matsunaga
authors.affiliation: Division of Medical Oncology, Department of Internal Medicine, Showa University Hospital, Hatanodai, Shinagawa, Tokyo 142-8666, Japan.
authors.forename: Toshikado
authors.initials: T
authors.lastname: Kaneta
authors.affiliation: Multidisciplinary Treatment Cancer Center, Kurume University Hospital, Kurume, Fukuoka 830-0011, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Miwa
authors.affiliation: Division of Medical Oncology, Department of Internal Medicine, Showa University Hospital, Hatanodai, Shinagawa, Tokyo 142-8666, Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Ichikawa
authors.affiliation: Division of Medical Oncology, Department of Internal Medicine, Showa University Hospital, Hatanodai, Shinagawa, Tokyo 142-8666, Japan.
authors.forename: Ken-Ichi
authors.initials: KI
authors.lastname: Fujita
authors.affiliation: Department of Medical Oncology, Kyorin University School of Medicine, Hinkawa, Mitaka, Tokyo 181-8611, Japan.
authors.forename: Fumio
authors.initials: F
authors.lastname: Nagashima
authors.affiliation: Department of Medical Oncology, Kyorin University School of Medicine, Hinkawa, Mitaka, Tokyo 181-8611, Japan.
authors.forename: Junji
authors.initials: J
authors.lastname: Furuse
authors.affiliation: Department of Diagnostic Pathology, Kurume University Hospital, Kurume, Fukuoka 830-0011, Japan.
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Kage
authors.affiliation: Department of Surgery, Kurume University Hospital, Kurume, Fukuoka 830-0011, Japan.
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Akagi
authors.affiliation: Division of Medical Oncology, Department of Internal Medicine, Showa University Hospital, Hatanodai, Shinagawa, Tokyo 142-8666, Japan.
authors.forename: Yasutsuna
authors.initials: Y
authors.lastname: Sasaki
keywords: KRAS mutation; Luminex xMAP; Scorpion-ARMS; colorectal cancer; direct sequencing; pyrosequencing