准确确定微卫星不稳定性 (MSI) 状态对于癌症患者的最佳治疗至关重要。传统的 MSI 标记有时会显示难以解释的微妙变化，尤其是在非结直肠病例中。我们评估了实验性的八个标记物组，包括用于检测 MSI 的长单核苷酸重复 (LMR) 标记物。这八个标记物组由五个常规标记物（BAT-25、BAT-26、NR-21、NR-24 和NR-27）和三个 LMR 标记（BAT-52、BAT-59 和 BAT-62）。通过 PCR 和毛细管电泳长度分析对 300 份结直肠癌、胃癌和子宫内膜癌样本进行 MSI 检测。使用 8 个标记物组进行的 MSI 检测显示与 IHC 分析的一致性为 99.3% (295/297)，排除 3 个 MMR 病灶缺陷案例。 BAT-59和BAT-62在胃癌和子宫内膜癌中的敏感性高于或相当于常规标志物。与胃癌和子宫内膜癌的传统标记相比，LMR 标记的平均位移大小更大。八个标记组的 MSI 测试显示出与 IHC 分析相当的性能。 LMR 标记物，特别是 BAT-59 和 BAT-62，表现出高灵敏度和大变化，这有助于提高 MSI 分类的可信度，特别是在胃癌和子宫内膜癌中。需要对大量样本进行进一步研究来验证这些 LMR 标记。© 2023。作者。

Accurate determination of microsatellite instability (MSI) status is critical for optimal treatment in cancer patients. Conventional MSI markers can sometimes display subtle shifts that are difficult to interpret, especially in non-colorectal cases. We evaluated an experimental eight marker-panel including long mononucleotide repeat (LMR) markers for detection of MSI.The eight marker-panel was comprised of five conventional markers (BAT-25, BAT-26, NR-21, NR-24, and NR-27) and three LMR markers (BAT-52, BAT-59 and BAT-62). MSI testing was performed against 300 specimens of colorectal, gastric, and endometrial cancers through PCR followed by capillary electrophoresis length analysis.The MSI testing with eight marker-panel showed 99.3% (295/297) concordance with IHC analysis excluding 3 MMR-focal deficient cases. The sensitivity of BAT-59 and BAT-62 was higher than or comparable to that of conventional markers in gastric and endometrial cancer. The mean shift size was larger in LMR markers compared to conventional markers for gastric and endometrial cancers.The MSI testing with eight maker-panel showed comparable performance with IHC analysis. The LMR markers, especially BAT-59 and BAT-62, showed high sensitivity and large shifts which can contribute to increased confidence in MSI classification, especially in gastric and endometrial cancers. Further study is needed with large number of samples for the validation of these LMR markers.© 2023. The Author(s).