TEST:

OncoMate™ MSI

PCR analysis using the Promega OncoMate® MSI Dx Analysis System with an investigational data interpretation software correlates with evaluation of MMR expression by IHC in 94% of cases, among the tumor types evaluated. MSI-high results reliably (100% in this sample) predict loss of MMR protein IHC staining, but occasional cases yield MSS results while having MMR loss by IHC.

Concordance between MMR IHC and the Oncomate MSI PCR assay was 100% for CRC but for other cancers may be lower. The MSI PCR test has low sensitivity in cases with isolated MSH6 loss, supporting the recommendation that MMR IHC may be favored over PCR in cancers such as those of endometrium.

This new NGS-based MSI detection method outperforms previously published methods (i.e. Idylla, OncoMate MSI Dx, and Foundation One® CDx). Although highly efficient, Octaplex CaBio-MSID requires validation in a larger independent series of different tumor types.

Our testing with the OncoMate MSI Dx Analysis System (Promega) matched for all the expected results. This MSI analysis protocol has been deemed acceptable based on our validation studies and will be used in clinical testing.

The Idylla MSI Test is a clinically valid method for dMMR screening in CRC patients, and results of this testing can be used to guide further evaluation of individuals for Lynch syndrome. All percentage agreement point estimates used to determine the success of the study exceeded the 90% benchmark established a priori.

The Promega OncoMate MSI Dx analysis system shows excellent concordance with the previous Promega MSI analysis system v1.2 and MMR IHC in CRC tumor samples, and has clinical utility in screening for LS in CRC patients.

IHC testing in our study incorrectly defined MSI status in 5%, which can be considered as a high error rate. We suggest parallel testing as an alternative approach for MSI/MMRD detection in malignant tumors to achieve correct identification of patients with Lynch syndrome and to detect the ones who qualify for immunotherapy.

"Otherwise, HRM approaches and microcapillary electrophoresis platform failed to detect MSI-ECs showing minimal microsatellite shifts. In conclusion, whereas in colorectal site several technologies are eligible for MSI test, in ECs MSI test should be based on fluorescent capillary electrophoresis as it identifies a higher proportion of cases that could be misdiagnosed with other strategies."

Learn about the clinical performance of the new OncoMate™ MSI Dx Analysis System, the industry’s first FDA-cleared, PCR-based diagnostic kit for MSI status. The system uses an improved format of the most globally relied upon gold standard loci, which are recommended by NCCN Clinical Practice Guidelines In Oncology (NCCN Guidelines®) and other leading cancer organization guidelines.

– Jeff Bacher, Sr Research Scientist 2, Promega Clinical Utility of MSI testing for Lynch syndrome and anti-PD1 immunotherapy: The Pathologists Perspective. – Dr Anca Oniscu, Consultant Pathologist and Clinical Lead for Molecular Pathology, Laboratory Medicine, Edinburgh Royal Infirmary.