Table 3:
Summary of MMR immunohistochemistry, MSI polymerase chain reaction, tumor mutational burden and MSI Score/Sensor in Lynch Syndrome cohort
| Case | MMR Status (IHC) |
Second Hit in MMR genes (MSK-IMPACT) |
MSI Status (PCR) |
Signature Category by Exposure_SigMA |
TMB Score (mut/Mb) |
MSI Score |
MSI Sensor |
|---|---|---|---|---|---|---|---|
| 1 | Retained | No | MSS | Aging | 5.3 | 1.07 | Stable (Liver Metastasis) |
| 2 | Retained | No | MSS | HRD | 3.5 | 0.05 | Stable |
| 3 | Retained | Yes (LOH) | MSS | N/A | 2.6 | 0.58 | Stable |
| 4 | Loss of MLH1 and PMS2, partial loss of MSH6 | Yes (LOH) | MSI | MSI | 16.7 | 7.24 | Indeterminate |
| 5 | Retained | No | MSS | APOBEC | 3.5 | 0 | N/A |
| 6 | Loss of MSH6 | Yes (Somatic) | Indeterminate | MSI | 20.2 | 3.56 | Indeterminate |
| 7 | N/A | N/A | MSS | Sig 17 | 3.5 | 0.25 | Stable |
| 8 | Retained | No | MSS | Aging | 3.5 | 0.12 | Stable |
| 9 | Retained | N/A | N/A | N/A | N/A | N/A | N/A |
| 10 | Loss of MSH2 and MSH6 | No | MSI | MSI | 24.84 | 11.5 | High |
| 11 | Loss of MSH2 and MSH6 | N/A | N/A | N/A | N/A | N/A | N/A |
| 12 | Retained | No | MSS | N/A | 1.05 | 0.57 | Stable |
| 13 | Loss of MLH1 and PMS2 | Yes (LOH) | MSI | MSI | 8.39 | 7.68 | Indeterminate |
Abbreviations: MMR, mismatch repair protein; IHC, immunohistochemistry; MSI, microsatellite instability; PCR, polymerase chain reaction; TMB, tumor mutational burden (somatic mutations per Megabase (mut/Mb); MSS, Microsatellite stable; LOH, loss of heterozygosity; HRD; Homologous repair deficiency; N/A, not available.