Is my tumor MSI-High or MSS, and how does this affect treatment
Ask Navis about your situation
This answer is general. Get one about your specific case — no signup, answered right here.
For informational purposes only
This answer was generated by AI grounded in NCCN guidelines and published medical literature. It is not medical advice. Always consult your oncologist or care team before making treatment decisions.
Sources & medical oversight
- Grounded in NCCN Guidelines for Patients: Colon Cancer — the same guidelines oncologists use.
- Developed under the medical oversight of OpenCancer’s physician-scientist team (Chris Apfel, MD/PhD/MBA, CMO · Kaumudi Bhawe, PhD, CSO).
- Last updated July 13, 2026. Informational only — not a substitute for your oncology team.
To answer your question, I would need:
- Your pathology report or tumor testing results
- Any molecular testing reports (like immunohistochemistry, PCR, or sequencing results)
- Lab reports that specifically mention "MSI" (microsatellite instability) status
Once you share those documents, I can explain:
- Whether your results show MSI-High or MSS (microsatellite stable)
- What that finding means in plain language
- How it typically influences colorectal cancer treatment decisions
Quick Educational Context (While You Gather Records):
MSI Status Basics: According to CancerPatientLab educational resources, microsatellite instability (MSI) refers to errors in your tumor's DNA that aren't being corrected properly. Think of it like a typewriter without spell-check—mistakes accumulate and aren't fixed.
- MSI-High tumors typically respond well to immunotherapy drugs (like pembrolizumab/Keytruda)
- MSS tumors usually follow different treatment pathways
This distinction is important because it's one of the first "tissue-agnostic" biomarkers approved by the FDA—meaning the treatment recommendation is based on what the tumor is made of, not just where it started in your body.
Please upload your test results, and I'll provide a detailed educational interpretation.
This information is for educational purposes only. Always consult your healthcare team for personalized medical advice and decisions.
Ask Navis about your case
That answer is general. Ask about your specific situation — no signup, answered right here.
Facing this with someone you love?
Keep the whole picture in one private place: records, a plain-language summary of where things stand, questions, and the people helping. Navis keeps it up to date so no one has to re-explain the story. Free, and only the people you invite can ever see it.
Start a care circle →Source Guidelines
NCCN Guidelines for Patients: Colon Cancer (2026)Browse all NCCN Guidelines for Patients →Related Services
Services that may help with treatment for Colorectal Cancer patients
Have your records handy? Upload them for a deeper, personalized analysis →
Related Questions
Use the above evidence to inform your response when relevant. how do they determine results from chemoradiation to...
Good question. Here's what typically happens: The Assessment Process 9/3 labs + 9/8-9 visits Labs on 9/3: - Blood work to check your recovery blood
What questions should I ask my oncologist
I'd be happy to help you prepare for your appointment. To give you the most relevant questions, it would help to know: What's your current situation?