MSI-H gDNA Reference Standard for Cancer Test

Product Overview

The MSI-H gDNA Reference Standard for Cancer Test is a meticulously characterized genomic DNA reference material designed to validate microsatellite instability-high (MSI-H) detection assays in oncology diagnostics. Derived from mismatch repair-deficient cell lines, this standard exhibits the hallmark microsatellite instability patterns observed in approximately 15% of colorectal cancers and other tumor types. With a well-defined MSI-H profile across recommended markers, it serves as an essential control for ensuring accurate identification of MSI-H tumors, which have distinct prognostic and therapeutic implications including responsiveness to immune checkpoint inhibitors .

Product Features

Authentic MSI-H Signature

The standard contains gDNA with unstable microsatellites across the 5 consensus markers (BAT25, BAT26, D5S346, D2S123, and D17S250) plus additional markers for expanded panel validation. Each locus exhibits the characteristic length variations that define the MSI-H phenotype, verified by capillary electrophoresis and NGS .

Clinically Relevant Mutation Spectrum

In addition to microsatellite instability, the standard includes common somatic mutations associated with MSI-H tumors, such as mutations in TP53, PTEN, and PIK3CA, enabling simultaneous validation of mutation detection alongside MSI classification .

Quantitative Performance Metrics

The standard’s MSI-H status is quantified using the MSI Score, providing a numerical baseline for assay validation. This allows laboratories to establish objective thresholds for distinguishing MSI-H from MSS and MSI-Low samples .

Usage

Assay Validation Protocol

Incorporate the standard into validation runs to:

• Verify detection sensitivity for unstable microsatellites

• Establish MSI-H calling thresholds

• Monitor assay performance over time

• Compare results across different platforms or reagent lots

Multi-Platform Application

The standard is compatible with all major MSI detection methods:

• Fragment analysis by qPCR

• Targeted NGS panels

• Immunohistochemistry (when paired with FFPE controls)

• Digital PCR-based microsatellite analysis

Recommended Working Concentration

Dilute the standard to 5-20 ng/μL for optimal performance in most assays. Adjust based on specific platform requirements, with lower concentrations (5-10 ng/μL) recommended for NGS applications and higher concentrations (10-20 ng/μL) for qPCR .

FAQ

What defines the MSI-H status in this standard?

The standard meets the Bethesda Guidelines criteria for MSI-H, with instability detected in ≥2 of the 5 consensus microsatellite markers. This classification is confirmed by both molecular testing and MMR protein deficiency assessment .

How is this standard different from cell line-derived controls?

Unlike raw cell line DNA, this standard undergoes extensive characterization and normalization to ensure consistent MSI-H profiles across lots. It includes verified performance data across multiple platforms, saving laboratories time in validation .

Can it be used to validate MSI detection in liquid biopsies?

Yes, when diluted in wild-type plasma cfDNA, the standard can validate MSI detection in liquid biopsy workflows. This enables laboratories to establish limits of detection for MSI markers in circulating tumor DNA .

What storage conditions ensure long-term stability?

For maximum stability, store at -80°C for up to 5 years or at -20°C for 36 months. Avoid more than 5 freeze-thaw cycles to prevent DNA degradation. Aliquoting into single-use volumes is recommended .