Experimental Study Of IDH1mutations In Human Gliomas

Part I: The expression and significance of IDH1 mutations in 97 cases of human gliomaObjective: To investigate the expression and significance of isocitrate dehydrogenase (IDH) 1 mutation in human glioma of different sub-types.Methods: DNA direct sequence was used to detect 97 case of glioma and 9 case of other CNS tumor plus 10case of normal brain tissue.Results: IDH1 mutation was heterozygous and wild type arginine in position 132 was replaced by histidine (R132H). The expression in glioma of different sub-type was 0/5 in pilocytic astrocytoma (gradeⅠ), 15/22 in diffuse astrocytoma (gradeⅡ), 11/19in anaplastic astrocytoma(gradeⅢ), 1/6 in primary glioblastoma(gradeⅣ), 8/10 in econdary glioblastoma (gradeⅣ), 6/9 in oligodendroglioma (gradeⅡ), 4/7 in anaplastic oligodendroglioma (gradeⅢ), 4/6 in oligoastrocytoma (gradeⅡ), 3/4 in anaplastic oligoastrocytoma (gradeⅢ), 0/4 in ependymoma (gradeⅡ), 0/3 in anaplastic ependymoa (gradeⅢ), 0/2 in medulloblastoma (gradeⅣ), 0/9 in some other central CNS tumors, 0/10 in normal brain tissues.Conclusion:IDH1 mutation was somatic mutation and only find in glioma of some sub-types. It can used as a molecular critical of glioma sub-types. It can be used to distinguish pGB and sGB; With TP53 mutation and LOH 1p/19q, it can be used as a critical of some glioma; it can be used to distinguish PAI and AⅡcombining BRAF. PartⅡ: The Significance of detecting IDH1 mutations in glioma with IDH1^R132H anti-bodyObjective: To investigate the significance of IDH1^R132H Anti-body (IMab-1) in detecting IDH1 mutations in human gliomas.Methods: Immunohistochemistry and Western-blot analysis were used in detecting IDH1 mutations in human gliomas with IDH1^R132H Anti-body; compare the difference of IDH1 mutations detected by IDH1^R132H Anti-body between by DNA direct sequence.Results: Positive results of IDH1 mutations in difference subtype gliomas detected by immunohistochemistry, Western-blot analysis and DNA direct sequence are 0/0/0 in Pilocytic astrocytoma (gradeⅠ), 12/14/15 in diffuse astrocytoma (gradeⅡ), 10/11/11 in anaplastic astrocytoma(gradeⅢ), 1/1/1 in Primary glioblastoma(gradeⅣ), 7,7,8 in Secondary glioblastoma (gradeⅣ), 6/6/6 in oligodendroglioma (gradeⅡ), 3/3/4 in Anaplastic oligodendroglioma (gradeⅢ), 4/4/4 in OAⅡ, 3/3/3 in Anaplastic oligoastrocytoma (gradeⅢ), and no positive results were detected in other tumors. There is no statistically difference in detecting IDH1 mutations by three methods.Conclusion:Although detecting IDH1 mutations in glioma by immunohistochemistry and Western-blot with IDH1^R132H antibody has false negative, the superiority of this method are high accuracy and convenient operation . It's a good method to detect IDH1 mutations with IDH1^R132H antibody.