Case report: Microsatellite instability determination is not always black and white in Lynch syndrome diagnosis

Julieta E. Rodriguez, Damien Vasseur, Mohamed Amine Bani, Odile Cabaret, Sophie Cotteret, Martine Muleris, Veronica Golbarg, David Malka, Thomas Pudlarz, Olivier Caron, Cristina Smolenschi

    Research output: Contribution to journalArticlepeer-review

    Abstract

    Introduction: Microsatellite instability (MSI) is a genetic marker that is useful in the detection and treatment of Lynch syndrome (Sd). Although conventional techniques such as immunohistochemistry (IHC) and polymerase chain reaction (PCR) are the standards for MSI detection, the advent of next-generation sequencing (NGS) has offered new possibilities, especially with circulating DNA. Case report: We present the case of a 26-year-old patient with Lynch Sd and a BRAF-mutated metastatic colon cancer. The discordant MSI results between the conventional methods and NGS posed challenges in making treatment decisions. Subsequent NGS analysis revealed a high MSI status, leading to participation in an immunotherapy trial, with remarkable clinical response. Conclusion: This case emphasizes the importance of comprehensive molecular profiling and strong interdisciplinary collaborations, especially in cases with ambiguous MSI results.

    Original languageEnglish
    Article number1396869
    JournalFrontiers in Oncology
    Volume14
    DOIs
    Publication statusPublished - 1 Jan 2024

    Keywords

    • case report
    • circulating DNA
    • colorectal cancer
    • discordant MSI
    • next-generation sequencing

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