Microsatellite Instability
Use
Identify tumors with microsatellite instability. High-frequency microsatellite instability (MSI‑H) is associated with Lynch syndrome, but it is also found in 15% to 20% of sporadic colorectal and endometrial cancers. MSI‑High status may enhance the likelihood of tumor responsiveness to immune checkpoint inhibitor therapy. MSI‑H is a marker of underlying DNA mismatch repair defect but does not define specific gene mutations responsible for cancers.
Special Instructions
This assay needs both (1) DNA prepared from FFPE (formalin‑fixed and paraffin‑embedded) tumor tissue and (2) matched normal tissue (FFPE or blood). Please provide a copy of the pathology report. This test will be delayed if the pathology report is not received.
Limitations
This assay can detect 8% to 12% of mutant in a background of wild‑type genomic DNA. If direct testing for gene mutations responsible for Lynch syndrome is desired, please contact customer service. Developed by Labcorp, not FDA cleared or approved.
Methodology
PCR-based (PCR)
Biomarkers
Result Turnaround Time
10-14 days
Related Documents
For more information, please review the documents below
Specimen
Tissue (FFPE)
Volume
Eight unstained slides at 5 μM and one matching H&E slide or FFPE tissue block or 3‑5 mL whole blood
Minimum Volume
Samples with ≥4 mm² tumor and normal tissue surface area and ≥50% tumor content are preferred; 3 mL whole blood
Container
FFPE tissue block or slides, lavender‑top (EDTA) tube or green‑top (sodium heparin) tube, tan‑top (K2‑EDTA) tube or pink‑top (K2‑EDTA) tube
Storage Instructions
Blocks and slides at room temperature; whole blood at 2°C to 8°C
Causes for Rejection
Tumor block containing insufficient tumor tissue or no tumor; broken or stained slides. Whole blood: contaminated specimen; frozen whole blood received; leaking tube; clotted blood; hemolysis; specimen containing suspicious foreign material; quantity not sufficient for analysis