结直肠癌错配修复蛋白和微卫星不稳定检测的对比分析  

Testing mismatch repair proteins versus microsatellite instability in colorectal carcinoma

作　　者：陈琼荣[1] 王满香[1] 郭芳[1] 况晶[1] 方娜[1] 王明伟[1] 金苏[1] 吴德[1] 邓云特[1] 魏少忠[2] Chen Qiongrong;Wang Manxiang;Guo Fang;Kuang Jing;Fang Na;Wang Mingwei;Jin Su;Wu De;Deng Yunte;Wei Shaozhong(Department of Pathology Hubei Cancer Hospital, Wuhan 430079, China;2Department of Gastrointestinal Surgical Oncology,Hubei Cancer Hospital, Wuhan 430079, China)

机构地区：[1]湖北省肿瘤医院病理科,430079 [2]湖北省肿瘤医院胃肠肿瘤外科

出　　处：《中华结直肠疾病电子杂志》2016年第5期398-404,共7页Chinese Journal of Colorectal Diseases(Electronic Edition)

基　　金：湖北省卫生厅重点资助项目(No.JX6A06);湖北省自然科学基金重点资助项目(No.2013CFA078);湖北省自然科学基金资助项目(No.2013CFC022)

摘　　要：目的目前最常用的筛查结直肠癌DNA错配修复基因缺失的方法是免疫组化检测错配修复(MMR)基因相关蛋白的表达,以及基于PCR检测多个微卫星位点判断有否微卫星不稳定(MSI)这2种方法,本研究主要目的是比较这二种检测之间的一致性,并对分子病理室作室内质量控制。方法收集2014年8月至2015年10月湖北省肿瘤医院结直肠癌368例手术切除标本,免疫组化常规检测癌组织MLH1,PMS2,MSH2及MSH6这4种蛋白的表达。免疫组化显示任一蛋白完全缺失,判读为MMR蛋白缺失(d MMR);如癌细胞4个MMR有多少不等的核着色,判读为MMR无缺失(p MMR)。选取其中的65例行PCR-毛细管电泳法检测MSI,其中28例为p MMR,37例为d MMR。然后对这65例组织用PCR毛细管电泳法检测Bethesda推荐的5个微卫星位点。比对这65例患者上述二种检测结果之间的一致性,并分析、整理其临床病理特征。结果 368例结直肠癌中有37例免疫组化结果为d MMR中,其余331例为p MMR。37例中剔除2例后对其中35例行毛细管PCR法检测,显示高频MSI者32例,微卫星稳定(MSS)者3例。选取331例中的28例行PCR检测,显示MSS者27例,MSI-H者1例。免疫组化法检测的敏感度和特异性分别为97.0%和90.0%,PCR检测结果的敏感度和特异性分别为91.4%和96.4%;二者总的一致性为93.7%。伴MSI的结直肠癌原发灶以右半结肠最多见(占48.6%),病理形态以低分化腺癌伴淋巴细胞浸润和粘液分泌最常见,病理TNM分期以Ⅱ期和Ⅲ期为主。结论免疫组化检测MMR蛋白和基于PCR的毛细管电泳法检测MSI二者的一致性高,其中免疫组化法可以作为临床初筛结直肠癌微卫星不稳定性的一种经济而便捷的方法,值得推广。Objective Immunohistochemical(IHC) staining for mismatch repair (MMR) proteinsand PCR-based detection for microsatellite status are routinely performed on colorectal carcinoma (CRC)surgical samples. However, the concordance of the two detections, which is related to the quality control ofour molecular pathology laboratory, is unknown so far. So the main aim of this study is to compare thedifferences between the two analyses and to improve our work. Methods IHC analyzed the expression ofMLH1, PMS2, MSH2 and MSH6 which was performed on 368 cases of formalin-fixed paraffin-embedded(FFPE) CRC tissues. If any one protein is negative in all of cancer cells but positive in normal colorectalmucosa, the IHC staining was reported as mismatch repair defective (dMMR). If the four MMR proteins are expressed in the nucleus of one or more cancer cells, the IHC result was interpreted as mismatch repairproficient (pMMR). All of the 37 cases of dMMR and selected 28 cases of pMMR were tested by PCR-basedMSI analysis. Paired normal and cancer DNA samples isolated from the FFPE tissues were tested for MSIusing Bethesda recommended 5 markers (BAT25, BAT26, D2S123, D5S346, D17S250). At last the results ofIHC and PCR were compared and their concordance were analyzed. Results IHC analyses were performedon 368 cases of CRC, among which 37 cases were dMMR and 331 cases were pMMR. After excluding 2 casesfrom the 37 samples, the remained 35 samples were tested for MSI, among which 32 samples were high-levelmicrosatellite instability (MSI-H) and 3 samples were microsatellite stable (MSS). In addition, 28 cases ofpMMR samples were selected to be tested by PCR for MSI, among which 27 cases were MSS but one casewas MSI-H. The sensitivity and specificity of immunohistochemistry was 97.0% and 90.0%, separately, thesensitivity and specificity of PCR was 91.4% and 96.4%, separately, and the total concordance of the twodetections achieved 93.7%. The most common original site of dMMR CRC was right hemicolon (occupying48.6%), and the most common pathol

关 键 词：结直肠肿瘤 免疫组织化学 微卫星不稳定 错配修复蛋白 

分 类 号：R735.34[医药卫生—肿瘤]