免疫组织化学法与Sanger测序法对IDH1基因突变检测的比较分析

目的:采用免疫组织化学法(immunohistochemistry,IHC)、Sanger测序法分别对中枢神经系统肿瘤患者异柠檬酸脱氢酶1(isocitrate dehydrogenase 1,IDH1)基因进行突变检测,并对结果的一致性进行分析,为临床IDH1基因突变检测方法的选择提供指导依据。方法:运用IHC和Sanger测序法检测657例人脑胶质瘤及其他中枢神经系统肿瘤中IDH1基因突变。结果:IHC检测结果:657例样本中,230例发生IDH1基因突变,49例组织为少量阳、弱阳等可疑阳性;Sanger测序法检测发现255例存在IDH1基因突变,11例因DNA质量不佳无法获得可评估结果。IHC与Sanger测序法检测IDH1基因突变具有较好的一致性(Kappa=0.88),差异无统计学意义(P=0.49);IDH1基因突变主要发生在WHOⅡ~Ⅲ级的星形细胞瘤、少突胶质细胞瘤、间变星形细胞瘤、间变少突胶质细胞瘤以及WHOⅣ级的继发性胶质母细胞瘤中。结论:IHC检测IDH1基因突变的结果与Sanger测序法检测结果具有较好的一致性,IHC敏感性低于Sanger测序法,但特异性较高,且操作相对简单,适于临床普遍开展和推广;Sanger测序法敏感性高,可检测未知突变位点,IHC检测突变阴性及不确定的病例应进一步使用Sanger测序法验证。

Comparative Analysis of Immunohistochemistry and Sanger Sequencing for Detection of IDH1 Gene Mutations

Objective:To analyze sensitivity and consistency of immunohistochemistry(IHC)and Sanger sequencing for detecting mutations in IDH1 gene in patients with central nervous system tumors,and the consistency of the results,providing guidance for clinicians and pathologists to choose suitable methods for IDH1 mutation detection.Methods:IHC and Sanger sequencing were separately performed to detect IDH1 mutations in 657 cases of human gliomas and other central nervous system tumors.Results:IHC results showed that 230 out of 657 cases presented a definite positive staining pattern,while 49 cases presented an suspected positive staining pattern.Sanger sequencing results showed that IDH1 mutations was identified in 255 cases,and that 11 samples could not be evaluated due to poor DNA quality.IHC was consistent with Sanger sequencing in IDH1 mutation detection,and the difference is not significant(Kappa=0.88,P=0.49);IDH1 mutations mainly occurred in World Health OrganiZation(WHO)II-Ⅲgliomas such as astrocytoma,oligodendroglioma,anaplastic astrocytoma,anaplastic oligodendroglioma and WHO IV secondary glioblastoma.Conclusion:IHC is consistent with Sanger sequencing in IDH1 mutation detection.The former is less sensitive than the latter,but it is relatively easy to operate in most hospitals and laboratories.Sanger sequencing is able to detect unknown types of mutation,so it is suggested to further validate IDH1 mutations when IHC results are uncertain.