Expression of myelin basic protein and glial fibrillary acidic protein genes in human glial tumors

Abstract

Analysis of the expression of genes encoding myelin basic protein (MBP) and glial fibrillary acidic protein (GFAP) genes in human glial tumors was carried out for determination of the expression specificity of these genes according to tumor types and their malignancy. Low levels of MBP mRNA in astrocytoma specimens of malignancy grades II-IV and significantly higher levels in perifocal zone adjacent to them have been determined by Northern hybridization. Diffuse astrocytomas and anaplastic astrocytomas are characterized mostly by low level of MBP gene expression and high level of GFAP gene expression, but distinct subtypes of diffuse and anaplastic astrocytomas with high level of MBP gene and low level of GFAP gene expression can be also detected that may be the reflection of different oncogenic pathways. Very low levels or even absence of MBP mRNA were revealed in oligodendroglioma and all oligoastrocytomas. Thus, Northern hybridization data are correlated with Serial Analysis of Gene Expression (SAGE). Obtained results show that MBP is nonspecific marker for tumors of oligodendroglial origin, but determination of relative levels of MBP and GFAP mRNAs may be useful for glial tumors recognition. By such a way, these two genes together with previously found by us YKL-40 and TSC-22 can be included into the gene panel for the determination of so called "gene signatures" of brain tumors. However, severe requirements in relation to a clinical value of these "gene signatures" can not be formulated without their verification on plenty of clinical samples of tumors and valid control.