Alfa Internexin Expression in a Series of 137 Gliomas and its Correlation with Oligodentroglial Morphology IDH1, P53 SYN and EGFR Expression

Abstract

Background: Distinguishing glial subtypesbased on nuclear and cellular morphology alone is subjective,with significant interobserver variability, even among highlyexperienced neuropathologists. Geneticsubtyping of a given histological phenotype and robust biomarkershas improved the diagnostic and prognostic assessment. Recently, IDH1 (more rarely IDH2) mutations have been found in nearly 40% of gliomas and strongly predict lower grade in histology and better outcomes. Aim: To evaluate if expression of alpha-internexin (INA) can be used a reliable diagnostic, prognostic and cost-effectivemarker, a proneural gene-coding neurofilament interacting protein significantly correlated with oligodendroglial phenotype, 1p/19q codeletion as well as higher chemosensitivity and better prognosis to our study population. Matherial: We studied INA expression in 137gliomasand correlated it with pure oligodentroglialhistology, IDH1, p53, EGFR and SYN expression by immunohystochemestry.Results: INA was expressed in 72.2% of grade II oligodendrogliomas (n = 22), 62.5% of grade III oligodendrogliomas (n = 16), 57.2% of grade II oligoastrocytomas (n = 7), 66.7% of grade III oligoastrocytomas (n = 6), 66.7% of glioblastomas with oligodendroglial component (n = 12), 0% of grade I astrocytomas (n = 13), 0% of grade II astrocytomas (n = 4), 0% of grade III astrocytomas (n = 12) and 2.5% of glioblastomas and gliosarcomas (n = 40).INA was expressed by 27(71.1%) of pure oligodentrogliomas(n=38) versus 17(17.2%) of non pureoligodentrogliomas(n=99),Chi square was p < 10-4; Cramer’s V was 0.517; p <10-4, which show a very strong relationship.INA was expressed by 32(45.1%) of gliomas with IDH1 mutation (n=71) versus 12(18.2%) of gliomas without IDH1 mutation (n=66), Chi square was p < 0.001; Cramer’s V was 0.288; p < 0.001, which show a very strong relationship. INA was expressed by 26(27.4%) of gliomas with P53 mutation (n=95) versus 18(42.9%) of gliomas without P53 mutation (n=42), Chi square wasp=0.05 which show they were negatively correlated. INA was expressed by 30(50.0%) of gliomas with SYN expression (n=60) versus 14(18.2%) of gliomas without SYN expression (n=77), Chi square was p < 10-4; Cramer’s V was 0.338; p < 10-4, which show a very strong relationship. INA was expressed by 12(27.3%) of gliomas with EGFR expression (n = 44) versus 32(34.%) of gliomas without EGFR expression (n=44), Chi square was p=0.05 which show they were negatively correlated. Conclusion: INA expression is a fast, cheap and reliable diagnostic and prognostic marker, which helpsindentify patients of different prognostic groups in diffuse gliomas and should be used routinely in the pathologic diagnosis of glial tumours. Keywords: Glial tumuors, Alpha-internexin, IDH1, P53, Synaptophysine, EGFR protein.