MSI检测需聚焦主流与权威——5个位点检测Panel才是主流权威

时间:2022-01-06  来源:  作者: 我要纠错


由于微卫星不稳定(MSI)在泛癌种中具有明确且重要的临床检测意义,现已被国内外众多临床指南共识强烈推荐常规检测。临床对于MSI的检测需求越来越明确,是否检测MSI现已不再是问题,如何选择检测位点给患者带来最准确的检测结果才更加需要注意。

人类基因组中已知的微卫星位点数目已有1900万个[1],而如何在众多位点中选择最具有代表性的微卫星位点,国内外指南共识其实早有定论。纵观国内外指南,明确推荐用于MSI检测的Panel都是由五个位点组成,即美国癌症研究中心(NCI)提出的由两个单核苷酸位点和三个双核苷酸位点组成的2B3D NCI Panel(BAT-26、BAT-25、D5S346、D2S123、D17S250)和由5个单核苷酸位点组成的Promega Panel并且,5个位点的判定标准也是一致的:5个位点中,2个及以上的位点不稳定为MSI-H;5个位点中1个位点不稳定为MSI-L,5个位点均稳定为MSS[2]。目前没有任何指南推荐6个及6个以上的单核苷酸位点。

 

图 1 NCCN指南明确推荐5个位点组成的两套Panel以及判定标准

指南共识所推荐的两套位点中,2B3D NCI Panel从被提出以来一直被指南共识所推荐,其推荐地位从未被动摇。而5个单核苷酸位点Panel还是经过了较为复杂的演进过程,最初是法国人类多态性研究中心基于高加索人群数据提出的Pentaplex Panel(BAT25、BAT26、NR-21、NR-22、NR-24)[3],该Panel被Revised Bethesda指南推荐[4]。后来,美国Promega公司在Pentaplex Panel上做了进一步改进,将NR-22替换为Mono-27推出了Promega Panel(BAT-25、BAT-26、NR-21、NR-24、MONO-27)。基于此,NCCN指南推荐2B3D NCI Panel和以Promega Panel为主的5个单核苷酸位点Panel用于MSI检测,而没有任何指南推荐6个单核苷酸位点

 

表 1 不同检测Panel指南推荐与临床研究应用情况

同时,国内外各种PD-1/L1免疫检查点抑制剂的大型临床研究入组MSI-H患者的筛选位点都遵循了指南推荐,选择的2B3D NCI Panel或Promega Panel由5个位点组成的检测Panel,比如帕博利珠单抗的临床研究中以上两种Panel都使用过;纳武利尤单抗、阿维鲁单抗、德瓦鲁单抗的临床研究则更多使用的是2B3D NCI Panel。而目前公开的数据和研究中,没有任何临床研究是用的是5个位点以上的MSI检测Panel。因此,6个位点的检测Panel并没有免疫治疗伴随诊断的数据支持

 

图 2 大型临床研究采用5个位点的2B3D NCI Panel或单核苷酸位点

近日,市面上有些声音将某个由6个单核苷酸位点组成的Panel与指南共识推荐和临床研究中使用的Pentaplex Panel或Promega Panel混同,企图混淆视听。可以详细比较一下Pentaplex Panel、Promega Panel 和6个单核苷酸的Panel。

 

表 2 单核苷酸Panel位点信息

可以看出,6个单核苷酸位点与Pentaplex相比,少了NR-22位点,且多了NR-27和MONO-27位点,同时也比Promega Panel多一个NR-27位点。而基于国内人群不同检测Panel的MSI-H检出率的META分析结果显示,6个单核苷酸位点Panel的MSI-H整体检出率远低于5个单核苷酸的Promega Panel,所有组合中,检出率最高的还是2B3D NCI Panel[9]。

 

表 3 中国人群不同MSI检测Panel检出率汇总

那么同样是单核苷酸Panel,为什么6个单核苷酸比Promega的检出率低呢?我们发现,6个单核苷酸位点相比Promega位点多出了NR-27位点,这个位点是从哪里来的呢?我们在这一篇发表于Disease Markers(影响因子=3.434)杂志的文献中,发现了NR-27的选择原因。

 

图 3 由于NR22位点无法兼容,NR27位点引入Pentaplex Panel

在20年前,我们进行MSI检测时,大多是进行的单重PCR,操作是较为复杂的,于是研究者们希望能够开发多重PCR在一个单管中完成多个微卫星位点的检测进而简化流程。但是,在将Pentaplex Panel与多重PCR技术结合时,研究团队发现NR-22位点无法与其余四个位点在同一个单管中兼容,因此将NR-27位点引入,替代了Pentaplex的NR-22位点[24]。但是原文中,并没有阐述为什么会选择NR-27,也并没有对NR-27在人群中的敏感性。

这个NR-27位点在中国人群中并没有公开的研究数据或文献报道来证实其检测性能。而基于国外人群数据显示,NR-27位点的检测敏感性仅6%左右[25],6个位点组合加入NR-27位点很有可能会降低检测Panel的整体敏感性。并且6个单核苷酸位点的判读标准是不明确的,因为指南中根本没有推荐过任何大于5个位点的检测Panel。这些因素有可能就是6个单核苷酸位点MSI-H检出率相较5个位点的组合更低,更容易造成漏检的原因。

 

图 4 数据提示NR-27位点灵敏度不高

综上,无论是经典2B3D还是单核苷酸位点组合,指南推荐和有数据验证的主流位点都是5个位点组成的Panel,6个位点的检测panel没有任何指南推荐,且无任何伴随诊断的用药的数据基础。

1.Bai, W., et al., Screening of MSI detection loci and their heterogeneity in East Asian colorectal cancer patients. Cancer Med, 2019. 8(5): p. 2157-2166.

2.Network, N.C.C., NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®) Gastric Cancer Version 1.2021 2021.

3.Suraweera, N., et al., Evaluation of tumor microsatellite instability using five quasimonomorphic mononucleotide repeats and pentaplex PCR. Gastroenterology, 2002. 123(6): p. 1804-11.

4.Umar, A., et al., Revised Bethesda Guidelines for hereditary nonpolyposis colorectal cancer (Lynch syndrome) and microsatellite instability. J Natl Cancer Inst, 2004. 96(4): p. 261-268.

5.Marabelle, A., et al., Efficacy of Pembrolizumab in Patients With Noncolorectal High Microsatellite Instability/Mismatch Repair-Deficient Cancer: Results From the Phase II KEYNOTE-158 Study. J Clin Oncol, 2020. 38(1): p. 1-10.

6.Overman, M.J., et al., Durable Clinical Benefit With Nivolumab Plus Ipilimumab in DNA Mismatch Repair-Deficient/Microsatellite Instability-High Metastatic Colorectal Cancer. J Clin Oncol, 2018. 36(8): p. 773-779.

7.Kim, J.H., et al., A Phase II Study of Avelumab Monotherapy in Patients with Mismatch Repair-Deficient/Microsatellite Instability-High or POLE-Mutated Metastatic or Unresectable Colorectal Cancer. Cancer Res Treat, 2020. 52(4): p. 1135-1144.

8.Clinicaltrials-NCT03435107

9.Zhang, C., et al., Incidence and detection of high microsatellite instability in colorectal cancer in a Chinese population: a meta-analysis. 2020, 2020.

10.LI X, LIU QH. Study on Microsatellite Instability in Colorectal Cancer Patients with Familial Predisposition. J China Med Univ 2006;37:410-408.

11.Jin HY, Lai RS, Ding YJ, Xie L, Yang BL, Liu F, Ding SQ, Ge YS. Detection of microsatellite instability in colorectal cancer by fluorescence multiplex polymerase chain reaction and its clinical value. Zhonghua Wei Chang Wai Ke Za Zhi. 2007 May;10(3):217-20.

12.Yang BL, Gu YF. Microsatellite instability in sporadic colorectal cancer and its relationship with clinicopathological features. World Chinese Journal of Digestology 2007;15:1160-1164.

13.Jin P, Meng XM, Sheng JQ, et al. Clinicopathological Features of Non-familial Colorectal Cancer with High-frequency Microsatellite Instability. Chin Med Sci J 2010;25:228-232.

14.Meng WJ, Wang L, Yu YY, et al. Significance of microsatellite instability in sporadic stage II and III rectal cancer. Chongqing Med J 2010;39:2420-2426.

15.Peng JL, Tang T, Ye ZL, et al. The relationship of microsatellite instability state with loss of mismatch repair proteins and clinical pathological characteristics in sporadic colorectal cancers. Chin J Cancer Biother 2015;22:479-483.

16.Zhou LY, Wan MZ, Liu YP, et al. Assessment of Microsatallite Instability in Colorectal Carcinoma: A Comparison Between Immunohistochemistry and PCR Method. Cancer Res Prev Treat 2015;42:1231-1234.

17.Yan WY, Hu J, Xie L, et al. Prediction of biological behavior and prognosis of colorectal cancer patients by tumor MSI/MMR in the Chinese population. Onco Targets Ther 2016;9:7415-7424.

18.Zheng JM, Huang BX, Nie X, et al. The clinicopathological features and prognosis of tumor MSI in East Asian colorectal cancer patients using NCI panel. Future Oncol 2018;14:1355-1364.

19.Jiang N. Relationship between microsatellite instability and clinicopathological features and prognosis in sporadic colorectal cancer. Acta Universitatis Medicinalis Anhui 2019;54:139-142.

20.Huang YQ, Yuan Y, Ge WT, et al. Comparative features of colorectal and gastric cancers with microsatellite instability in Chinese patients. J Zhejiang Univ-SC B 2010;11:647-653.

21.Li WQ, Li HN, Liu RQ, et al. Comprehensive Analysis of the Relationship Between RAS and RAF Mutations and MSI Status of Colorectal Cancer in Northeastern China. Cell Physiol Biochem 2018;50:1496-1509.

22.Wang Z, Tang XL, Wu XQ, et al. Mismatch Repair status between primary colorectal tumor and metastatic tumor, a retrospective consistent study. Biosci Rep 2019;39:BSR20190730.

23.Song YL, Wang LL, Ran WW, et al. Effect of Tumor Location on Clinicopathological and Molecular Markers in Colorectal Cancer in Eastern China Patients: An Analysis of 2,356 Cases. Front Genet 2020;11:96.

24.Buhard, O., et al., Quasimonomorphic mononucleotide repeats for high-level microsatellite instability analysis. Dis Markers, 2004. 20(4-5): p. 251-7.

25.Nouri Nojadeh, J., et al., Evaluation of microsatellite instability in tumor and tumor marginal samples of sporadic colorectal cancer using mononucleotide markers. EXCLI J, 2018. 17: p. 945-951.

  • 上一篇:患了脂肪肝,缩胃手术来帮你!
  • 下一篇:返回列表
  • 无相关信息
    健康知识

    健康图文信息
    推荐信息

    相关文章

    无相关信息

    栏目更新