Comparison of immunohistochemistry, PCR, and NGS for the evaluation of mismatch repair deficiency and microsatellite instability in colorectal cancer: a retrospective study.
Polymerase chain reaction and next-generation sequencing showed near-perfect agreement for detecting microsatellite instability in colorectal cancer.
Comparison of immunohistochemistry, PCR, and NGS for the evaluation of mismatch repair deficiency and microsatellite instability in colorectal cancer: a retrospective study.
Microsatellite instability (microsatellite instability) and mismatch repair (mismatch repair) deficiency serves as a critical predictive biomarker for the efficacy of immune checkpoint inhibitors (immune checkpoint inhibitors) in colorectal cancer (colorectal cancer).
This study aimed to evaluate the concordance of mismatch repair status and microsatellite instability assessment across three commonly used methods and to explore factors underlying discordant cases.
We retrospectively analyzed microsatellite instability status in 534 colorectal cancer immunohistochemistry (immunohistochemistry) for mismatch repair protein expression, and polymerase chain reaction (polymerase chain reaction) and next-generation sequencing (next-generation sequencing) for microsatellite instability status assessment.
Discordant results occurred in five cases (0.9%), primarily attributable to assay-specific limitations, tumor heterogeneity, technical or pre-analytical issues, and biological variability.
Immunohistochemistry, polymerase chain reaction, and next-generation sequencing showed high overall concordance in microsatellite instability and mismatch repair assessment.
The small number of discordant cases highlights the inherent limitations of individual methods.
While single-method testing is generally reliable, multi-platform evaluation may provide additional insights in diagnostically challenging or borderline cases.