microsatellite stable
Describes tumors with intact DNA mismatch repair mechanisms, typically associated with lower response to immunotherapy.
Full Definition
Microsatellite stable (MSS) tumors have functioning DNA mismatch repair systems and do not exhibit the high mutation burden characteristic of microsatellite instability-high (MSI-H) tumors. MSS represents the majority of colorectal cancers and many other solid tumors. These tumors typically have lower tumor mutation burden, reduced neoantigen presentation, and consequently lower response rates to immune checkpoint inhibitors compared to MSI-H tumors. MSS status influences treatment selection, particularly regarding immunotherapy eligibility and the choice of chemotherapy regimens.
Usage
Usage note: Use 'MSS' as the preferred abbreviation in clinical documentation.
In Context
- "The colorectal adenocarcinoma was microsatellite stable by PCR analysis." — Molecular pathology report
- "MSS status indicated that immunotherapy was unlikely to be beneficial." — Treatment recommendation