External quality assessment for the molecular detection of microsatellite instability in China, 2021-2022

ABSTRACTBackground Microsatellite instability (MSI) analysis of tumors informs Lynch syndrome testing, therapeutic choice, and prognosis. The status of MSI is mainly detected by polymerase chain reaction coupled with capillary electrophoresis. However, there are various assays with different detection loci and the obtained results may vary. The objective of this study was to evaluate the concordance among different assays and the performance among different laboratories.Methods External quality assessment (EQA) for the detection of MSI was performed in 2021 and 2022. Each sample panel consisted of five samples, including microsatellite-stable and MSI tumor tissues. The sample panels were coded at random, and the returned results were compared and scored.Results The fully validated sample panels showed appropriate applicability with commercially available assays. There were eight false-negative results in 2021 and five false results (two false-positives and three false-negatives) in 2022. Among the participating laboratories, in 2021, 20 (74.07%) provided completely correct results; in 2022, 38 (92.68%) obtained an optimal score.Conclusion The molecular detection of MSI in China exhibited an improvement in a 2-year EQA study. Participation in EQA program is an efficient way of assessing the performance of laboratories and improving their ability.KEYWORDS: Colorectal cancermicrosatellite instabilitydeficient mismatch repairmolecular detectionexternal quality assessment Declaration of interestsThe authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.Reviewer disclosuresPeer reviewers on this manuscript have no relevant financial or other relationships to disclose.Author contributionsAll authors have accepted responsibility for the entire content of this manuscript and approved its submission. Xiaoyu Fan designed the study and wrote the manuscript; Qianming Bai performed sample preparation, histopathological diagnosis and data analysis; Chunli Shi performed the experiments; Yanqun Xiao and Xueliang Wang supervised the project, designed the study, and approved the final article.AcknowledgmentsThe authors would like to thank Natural Science Foundation of Shanghai, Shanghai Municipal Health Commission, and Shanghai Center for Clinical Laboratory for financial supports of this study.Data availability statementThe data used to support the findings of this study are available from the corresponding authors upon reasonable request.Ethical approvalWritten informed consent was obtained from all patients prior to sample collection. Research involving human subjects complied with all relevant national regulations, institutional policies and is in accordance with the tenets of the Helsinki Declaration (as revised in 2013). The study was approved by the Ethics Committee of Shanghai Center for Clinical Laboratory (NO.202301).Supplemental dataSupplemental data for this article can be accessed online at https://doi.org/10.1080/14737159.2023.2257133.Additional informationFundingThis work was sponsored by Natural Science Foundation of Shanghai [NO:21ZR1455900, NO:22ZR1454400]; Shanghai Municipal Health Commission [NO:201940264, NO:202140388, NO:Youth Medical Talents–Clinical Laboratory Practitioner Program of Shanghai “Rising Stars of Medical Talents” Youth Development Program]; and Shanghai Center for Clinical Laboratory [NO:2021ZXKT-01].