Microsatellite instability testing in colorectal cancer using the QiaXcel advanced platform

Background: Microsatellite instability (MSI) is a major predictive and diagnostic marker in several cancers including colorectal carcinomas. Diagnostic testing for microsatellites is generally performed using capillary sequencers, which requires expensive high-end equipment including expensive chemistry using fluorescent dyes labelling the PCR products of interest. In this study we have modified such a diagnostic protocol and established the microsatellite testing on the QiaXcel Advanced platform. Methods: MSI testing was based on a previously established protocol describing a multiplex PCR followed by fluorescent detection of PCR products in a capillary sequencing device. Ten microsatellites were included in the new protocol: BAT25, BAT26, BAT40, D2s123, D10s197, D13s153, D17s250, D18s58, D5s346, and MycI. In this protocol the PCR was demultiplexed and established on the QiaXcel Advanced system (Qiagen, Hilden, Germany). Results: Making use of a series of FFPE control samples with known MSI status including those with and without MSI a protocol for MSI testing was successfully established on the QiaXcel Advanced platform. Conclusions: MSI testing for human colorectal cancers using the QiaXcel Advanced system could serve as an economic acceptable tool for rapid diagnostics in laboratories that do not have access to a capillary sequencing unit.