title: Interlaboratory comparison of K-ras testing by real-time PCR and RFLP in colorectal cancer samples.
abstract: Activating mutations of K-ras have been described in approximately 40% of patients with colorectal cancer, and are associated with resistance to epidermal growth factor receptor-targeted antibodies, such as cetuximab and panitumumab. Cost-effective and easy methods to determine K-ras mutations are urgently needed. Samples from 31 patients were tested. In laboratory 1, a real-time polymerase chain reaction (PCR)-based technique was used. All samples (n=31) were additionally tested using a restriction fragment length polymorphism (RFLP) analysis in laboratory 2. All results were confirmed by direct sequencing. In the first run, a concordance of real-time PCR and RFLP was observed in 77.4% (24 of 31) of samples. After resampling and reevaluation, a concordance of 93.5% (30 of 31) could be achieved. One of 7 (6.5%) initial discordant cases showed a mutation using real-time PCR and no mutation using RFLP, but the mutation was confirmed by direct sequencing. Real-time PCR and RFLP can be considered as valid K-ras mutation detection techniques. However, in patient probes with lower amounts of tumor cells and wild-type K-ras, reanalysis of further tumor tissue is recommended.
authors.affiliation: Department of Hematology and Oncology, Hospital Franz Tappeiner, Rossinistr, Merano, Italy. andrea.lanthaler@asbmeran-o.it
authors.forename: Andrea Judith
authors.initials: AJ
authors.lastname: Lanthaler
authors.forename: Gilbert
authors.initials: G
authors.lastname: Spizzo
authors.forename: Manfred
authors.initials: M
authors.lastname: Mitterer
authors.forename: Christine
authors.initials: C
authors.lastname: Mian
authors.forename: Guido
authors.initials: G
authors.lastname: Mazzoleni
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D057089:Pathology, Molecular / Q000379:methods*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012150:Polymorphism, Restriction Fragment Length; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016283:Proto-Oncogene Proteins p21(ras); D012680:Sensitivity and Specificity; D018631:ras Proteins / Q000235:genetics*
chemical_list: C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins