Tell me about the MSI-H biomarker

MSI-H Biomarker in Marlo's Case

I've reviewed the available documents in your [ID removed] and I want to be direct with you: I don't see specific mention of MSI-H (Microsatellite Instability-High) testing results in the documents that were successfully extracted and made available to me.

Here's what I did find regarding molecular testing:

What Testing Was Done

From the pathology reports and molecular profiling documents, Marlo's tumor has undergone:

• OncoKids panel - Negative for clinically significant variants
• CMA (Chromosomal Microarray) - Negative
• RNA-Seq Gene Fusions - Negative for clinically significant fusions
• Exome Sequencing (WES) - Performed as part of comprehensive analysis
• Whole Genome Sequencing (WGS) - Completed for structural variant detection
• Immunohistochemistry (IHC) - Multiple stains performed at CHLA

Why MSI-H Matters for Spindle Cell Sarcoma

For context, MSI-H status is important because:

• It indicates defective DNA mismatch repair
• Can predict response to immunotherapy (checkpoint inhibitors like anti-PD-1)
• Helps guide treatment decisions across many cancer types

What You Should Ask Your Team

Since MSI-H testing may not be clearly documented in the available records, here are specific questions for your oncology team:

1. "Has Marlo's tumor been tested for MSI-H (microsatellite instability) status?"
2. "If not, is MSI-H testing recommended as part of the comprehensive molecular workup?"
3. "How would MSI-H status, if present, change our treatment approach?"
4. "Are there other DNA repair gene mutations (like BRCA1/2, MLH1, MSH2, MSH6, PMS2) that have been tested?"

Next Steps

The "Optimal Tissue Testing Plan" document mentions comprehensive molecular profiling through multiple vendors (BostonGene, CD Genomics, Archer Sequencing). MSI-H testing may be included in these panels, but I'd recommend confirming directly with your care team.

This information is for educational purposes only. Always consult your healthcare team for personalized medical advice and decisions.