MSI-H (microsatellite instability-high) CRC is the primary biomarker for first-line pembr...
Deterministic view of the source YAML entity. Clinical authority remains with the cited source IDs and reviewer sign-off state.
| ID | BMA-MSI-STATUS-CRC |
|---|---|
| Type | Actionability |
| Status | reviewed 2026-05-07 | actionability review required |
| Diseases | DIS-CRC |
| Sources | SRC-ESMO-CRC-2024 SRC-KEYNOTE-177-ANDRE-2020 SRC-NCCN-COLON-2025 |
Actionability Facts
| Biomarker | BIO-MSI-STATUS |
|---|---|
| Variant | MSI-H |
| Disease | DIS-CRC |
| ESCAT tier | IA |
| Recommended combinations | pembrolizumab monotherapy (MSI-H 1L mCRC per SRC-KEYNOTE-177-ANDRE-2020, SRC-NCCN-COLON-2025), pembrolizumab monotherapy (tumor-agnostic MSI-H per SRC-ESMO-CRC-2024) |
| Evidence summary | MSI-H (microsatellite instability-high) CRC is the primary biomarker for first-line pembrolizumab monotherapy (KEYNOTE-177; mPFS 16.5 vs 8.2 mo, HR 0.60; FDA-approved 2020 for 1L mCRC MSI-H). Pembrolizumab is also FDA-approved tumor-agnostically for MSI-H/dMMR solid tumors (KEYNOTE-158, 2017). MSS/pMMR CRC does not benefit from ICI monotherapy. MSI-H (~5% of metastatic CRC) is typically detected by PCR-based fragment analysis or NGS; result correlates closely with IHC-based dMMR testing (MLH1/MSH2/MSH6/PMS2 loss). Threshold selection (MSI-H positive/negative) enforced by algorithm layer; this BMA entry surfaces ESCAT tier context only. For Lynch syndrome germline implications see BMA entries for BIO-MLH1 / BIO-MSH2 / BIO-MSH6 / BIO-PMS2. |
Notes
Variant_qualifier: "MSI-H" — only matches positive MSI-H values; MSS/pMMR falls through to a different pathway. Gene-stem matching ("MSI") does not intersect with BIO-DMMR-IHC BMA entries (stem "DMMR") — these are complementary, not overlapping. KEYNOTE-158 source stub not yet ingested separately; ESMO CRC 2024 covers the tumor-agnostic context.
Used By
No reverse references found in the YAML corpus.