TABLE 2.
Concordance/Discordance of NGS-MSI and IHC-MMR After CPR for CRC, GE, SB, and EC Tumors
| Subgroup | No. of Samples with IHC and MSI Data | No. of MMRp/MSI-H Samples Undergoing Pathology Review | MMRp After Pathology Review | % Discrepant Cases Resolved | Percent Discordant Postreview |
|---|---|---|---|---|---|
| CRC MMRp/MSI-H | 30,835 | 49 | 46 | 6 | 0.15 |
| GE MMRp/MSI-H | 10,743 | 9 | 4 | 56 | 0.04 |
| SB MMRp/MSI-H | 1,528 | 4 | 3 | 25 | 0.20 |
| EC MMRp/MSI-H | 15,150 | 42 | 30 | 29 | 0.20 |
| Combined MMRp/MSI-H | 58,256 | 104 | 83 | 20 | 0.14 |
| Subgroup | No. of Samples With IHC and MSI Data | No. of MMRd/MSS Samples Undergoing Pathology Review | MMRd After Pathology Review | % Discrepant Cases Resolved | Percent Discordant Postreview |
|---|---|---|---|---|---|
| CRC MMRd/MSS | 30,835 | 25 | 24 | 4 | 0.08 |
| GE MMRd/MSS | 10,743 | 22 | 21 | 5 | 0.20 |
| SB MMRd/MSS | 1,528 | 3 | 3 | 0 | 0.20 |
| EC MMRd/MSS | 15,150 | 48 | 46 | 4 | 0.30 |
| Combined MMRd/MSS | 58,256 | 98 | 94 | 4 | 0.16 |
Abbreviations: CPR, central pathology review; CRC, colorectal carcinoma; EC, endometrial carcinoma; GE, gastroesophageal; IHC, immunohistochemistry; MMRd, mismatch repair deficient; MMRp, mismatch repair proficient; MSI-H, microsatellite instability high; MSS, microsatellite stable; NGS-MSI, next-generation sequencing assessment of microsatellite instability; SB, small bowel.