BRAF mutation in sporadic colorectal cancer and Lynch syndrome
BRAF mutation in sporadic colorectal cancer and Lynch syndrome
复制标题
DOI：
10.1007/s00428-013-1470-9
复制
发表时间：
2013-11-01
期刊：
影响因子：
3.5
通讯作者：
Ristimaki, Ari
中科院分区：
文献类型：
--
作者：
Thiel, Alexandra;Heinonen, Mira;Ristimaki, Ari
本研究的目的是检测结直肠癌中BRAF癌基因的突变，并利用这些信息来识别Lynch综合征患者。采用免疫组织化学（IHC）分析了连续性原发性结直肠癌病例（n = 137）的MLH 1蛋白表达。使用特异性单克隆抗体（VE 1）通过IHC和qPCR检测BRAF V600 E突变。所有MLH 1蛋白阴性病例均进行微卫星不稳定性分析和MLH 1启动子甲基化检测。MLH 1蛋白表达缺陷和高微卫星不稳定性（MSI-H）在137例连续结直肠癌标本中检测到18例（13.1%）。与qPCR相比，通过IHC检测BRAF V600 E突变的灵敏度和特异性为100%，并且该突变经常存在于MSI-H组中（77.8%; 14/18），而在微卫星稳定组中的频率较低（7.6%; 9/118）。MSI-H组的所有BRAF V600 E突变病例均存在MLH 1启动子甲基化（14/14），如通过甲基化特异性多重连接依赖性探针扩增检测到的。当MSI-H组中BRAF为野生型时，仅检测到一个MLH 1启动子甲基化（1/4），在其余三个没有MLH 1甲基化的病例中，两个被鉴定为具有与Lynch综合征一致的MLH 1突变。最后，对11例先前确诊的林奇综合征病例进行了BRAF V600 E突变分析，所有病例均为野生型。总之，通过IHC检测结直肠癌标本中的BRAF V600 E是敏感和特异的，可能有助于识别Lynch综合征患者。
The aim of the study was to detect mutations of BRAF oncogene in colorectal cancer and to use this information to identify Lynch syndrome patients. Consecutive cases of primary colorectal cancer (n = 137) were analyzed for MLH1 protein expression using immunohistochemistry (IHC). BRAF V600E mutation was detected by IHC using a specific monoclonal antibody (VE1) and by qPCR. All MLH1 protein-negative cases were subjected to microsatellite instability analysis and MLH1 promoter methylation assay. MLH1 protein expression deficiency and high microsatellite instability (MSI-H) were detected in 18 of the 137 (13.1 %) consecutive colorectal cancer specimens. Detection of the BRAF V600E mutation by IHC was 100 % sensitive and specific as compared to qPCR, and this mutation was frequently present in the MSI-H group (77.8 %; 14/18) and less frequently in the microsatellite-stable group (7.6 %; 9/118). All BRAF V600E mutated cases of the MSI-H group presented with a MLH1 promoter methylation (14/14) as detected by methylation-specific multiplex ligation-dependent probe amplification. When BRAF was wild type in the MSI-H group, only one MLH1 promoter methylation was detected (1/4), and of the remaining three cases without MLH1 methylation, two were identified to harbor an MLH1 mutation consistent with Lynch syndrome. Finally, 11 previously confirmed Lynch syndrome cases were analyzed for BRAF V600E mutation, and all of them were wild type. In conclusion, detection of BRAF V600E in colorectal cancer specimens by IHC is sensitive and specific and may help to identify Lynch syndrome patients.