Multicenter Evaluation of the Idylla NRAS-BRAF Mutation Test in Metastatic Colorectal Cancer

Treatment of colorectal cancer (CRC) with monoclonal antibodies against epidermal growth factor receptor requires the assessment of the mutationalstatus of exons 2, 3, and 4 of the NRAS and KRAS oncogenes. Moreover, the mutationalstatus of exon 15 of the BRAF oncogene is a marker of poor prognosis in CRC. The Idylla NRAS-BRAF Mutation Testis a reliable, simple ( NRAS (18 mutations) and BRAF (5 mutations). A multicenter study was conducted in 14 centers using the Idylla NRAS-BRAF Mutation Testto assess the NRAS and BRAF mutationalstatus of 418 formalin-fixed, paraffin-embedded tissue samples from CRC patients. Results were compared with those obtained earlier by routine reference methods, including next-generation sequencing, pyrosequencing, mass spectrometry–based assays, PCR-based assays, and Sanger sequencing. In case of discordance, additional tests were performed by digital droplet PCR. Overall, after testing confirmation and excluding invalids/errors by design, concordances between the Idylla NRAS-BRAF Mutation Testand the reference test results were found in almost perfect agreement. In conclusion, the Idylla NRAS-BRAF Mutation Testenables the routine detection of all NRAS and BRAF mutationsdeemed clinically relevant according to the latest clinical guidelines, without necessitating molecular expertise or infrastructure.