Crosstalk of Cancer Genomic Test and Cancer Immune Therapy

Based on the"neoantigen theory", the measurement of microsatellite instability(MSI)and tumor mutation burden(TMB) is one of the essential test items during cancer precision medicine, especially for the administration of immune checkpoint inhibitor. The conventional MSI test is consist of direct PCR method to amplify the microsatellite region using DNA derived from tumor specimen as a companion diagnostic(CDx)for pembrolizumab, while the recent comprehensive genomic profiling test such as FoundationOne CDx also evaluate the MSI status. TMB is counted and reported as the number of the mutation per 1 Mb(mut/Mb), and the over 10 mut/Mb is the universal cut off for pembrolizumab CDx.