A well-defined subtype of colorectal cancer (CRC) is characterized by deficiencies in the mismatch repair (MMR) pathway. MMR status may impact prognosis and benefit of adjuvant chemotherapy. MLH1, MSH2, MSH6, and PMS2 protein expression (as assessed by IHC) and microsatellite instability analysis (MSI) assessed by PCR are well-established tools to screen for Lynch syndrome (LS), and such testing is recommended for all new colorectal cancer diagnoses. MMR IHC and molecular MSI testing also serve as companion diagnostic tests in a wide range of solid tumors for selection of certain immuno-oncology therapies.
Mismatch Repair (MMR) IHC Panel
- Immunohistochemistry (IHC)
- Epic Aura Integration
Specimen Requirements
A formalin-fixed, paraffin-embedded (FFPE) tissue block is preferred specimen type or one (1) unbaked, unstained slide for H&E staining (required) and two to three (2-3) positively charged unstained slides (all cut at 4-5 microns) for each test/antibody ordered.
Block and slide identifiers should be clearly written and match exactly with the specimen ID and specimen labeling as noted on the requisition.
Storage and Transportation
Use cold pack for transport, making sure cold pack is not in direct contact with specimen. NYS clients please provide date and time of Collection.
CPT Code(s)*
88342 x1, 88341 x 3 or 88360 x 4 or 88361 x 4
Turnaround time
1-2 Days
Global: 2 Days
Image Analysis (Tech-Only): 2 Days
Tech-Only (stain only): 24 Hours
Level of Service
- Global
- Tech Only
Integrations
- Epic Aura
New York Approved: Yes
*The CPT codes provided with our test descriptions are based on AMA guidelines and are for informational purposes only. Correct CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed.
Biomarkers
Immunohistochemistry (IHC)
| Expression | |||||
|---|---|---|---|---|---|
| MLH1 | MSH2 | MSH6 | PMS2 | ||
Last Updated: March 10, 2026