Evaluation of the Idylla KRAS and NRAS mutation test in colorectal cancer tissue

Introduction: The currently approved techniques for RAS mutations testing in colorectal cancer (CRC) tissue are labor-intensive and time consuming. The Idylla technology (IT) is a rapid and fully automated diagnostics system. The primary aim of this study is to compare the Idylla performance against that of conventional techniques (CT). Methodology: Archival CRC tumor samples from 2 hospitals were tested for KRAS and NRAS mutations using the IT. Results were compared to those obtained earlier by CT performed in accredited laboratories. Unexplained discordant results were verified locally by next generation sequencing (NGS) to ascertain the accuracy of IT. Results: Forty five samples were processed. All samples underwent dual testing (CT & IT) for KRAS mutations. IT identified mutations in 2 samples that were not detected by CT. Primary concordance rate for KRAS was 93.3% and the accuracy rate improved to 100% after verification and explanation of discordant results. Only 18 samples underwent dual testing for NRAS. Primary concordance and accuracy rates for NRAS were 94.4%. The mean time from dispatching the specimen for RAS testing by CT until receipt of results was 12 (7-28) days compared to few hours when IT was used. Conclusion: IT provides a quick and reliable mean for RAS testing. In addition, it identifies mutations that are not detected by CT and thus may provide better guidance to treatment choices.