摘要目的 探讨异柠檬酸盐脱氢酶1基因(isocitrate dehydrogenase 1 gene,IDH1)突变的表达产物IDH1R132H在人中枢神经系统胶质瘤中的表达及其在鉴别诊断中的意义.方法 应用免疫组织化学EnVision法检测不同级别胶质瘤75例(包括WHOⅡ级33例,Ⅲ级20例和Ⅳ级22例)与各种原因造成的胶质增生性脑组织中IDH1R132H的表达情况,并与p53的表达情况进行比较分析.结果 IDH1R132H在WHOⅡ级、Ⅲ级和Ⅳ级胶质瘤的表达阳性率分别为57.6%(19/33)、40.0%(8/20)和27.3%(6/22),差异有统计学意义(P=0.024).IDH1R132H的具体表达部位在胶质瘤细胞的胞质、突起以及部分细胞核.除肿瘤主体部分密集增生的肿瘤细胞呈阳性表达以外,包括皮质和白质在内的肿瘤周边区域单个或散在的肿瘤细胞也呈强阳性表达.IDH1R132H阳性病例有额叶受累为主的倾向.胶质增生组织、毛细胞型星形细胞瘤均为阴性表达.另外,p53在WHOⅡ级、Ⅲ级和Ⅳ级胶质瘤的表达阳性率分别为42.4%(14/33)、65.0%(13/20)和77.3%(17/22).IDH1R132H的表达与p53的表达之间没有明确的相关性(P=0.766).结论 IDH1R132H在各级别胶质瘤中均有表达,且随着肿瘤级别的增高呈表达下降趋势.IDH1R132H可以作为鉴别低级别胶质瘤和胶质增生性病变的一个有用的分子标志物.

abstractsObjective To investigate the immunohistochemical expression of isocitrate dehydrogenase 1 gene ( IDH1 ) R132H in glioma and its diagnostic utility. Methods Immunohistochemical study of IDH1R132H expression was performed on formalin-fixed paraffin-embedded tissue samples of 75 gliomas, including 33 cases of grade Ⅱ , 20 cases of grade Ⅲ and 22 cases of grade Ⅳ tumors. Six cases of pilocytic astrocytoma and 12 cases of gliosis were used as controls. Results Nineteen in 33 cases of grade Ⅱ (57.6%), 8 in 20 cases of grade Ⅲ (40. 0% ), 6 in 22 cases of grade Ⅳ (27. 3% ) showed positive cytoplasmic staining of IDH1R132H. Scattered invasive glioma cells at the tumor periphery also expressed IDH1R132H. Gliomas involving the frontal lobe showed more strong IDH1R132H staining. In contrast, none of the pilocytic astrocytomas and gliosis showed IDH1R132H staining. Moreover, the rate of p53 immunopositivities were 42. 4% ( 14/33 ) in grade Ⅱ , 65.0% (13/20) in grade Ⅲ and 77.3% (17/22) in grade Ⅳ gliomas. There were no statistic correlations between expression of IDH1R132H and p53.Conclusion IDH1R132H tends to express preferentially in low-grade gliomas, and it thus may serve as a valuable marker in distinguishing low grade gliomas from gliosis.