MSI Procedures

In 1998, the NCI published recommendations for a panel of 5 microsatellites to evaluate for the possibility of Lynch syndrome (Cancer Res 1998;58(22):5248-57). Two of the markers (BAT25 and BAT26) are mononucleotide repeats and 3 of the markers (D2S123, D5S346 and D17S250) are dinucleotide repeats.

Generally, microsatellite instability in mononucleotide repeats is more typical in Lynch syndrome-related tumors. If microsatellite instability is only detected in dinucleotide repeats, testing of additional mononucleotide markers may be helpful (JNCI 2004;96(4):261-8).