Oligodendrogliomas (OGs) are primary brain tumors, genetically characterized by chromosomal alterations in the 1p, 10q, 19q (LOH). Recent clinical trials have shown that anaplastic oligodendrogliomas (AOGs) possessing those LOH are sensitive to the chemotherapy and well controlled, yet AOGs without those LOH are insensitive and progressive, despite of their similar histological features. There is no information on the specific diagnostic markers or target molecules allowing for the recognition of OG cells in tumor tissues or understanding the sensitivity differences against the chemotherapy in two types of AOGs. To find out the molecular and genetic markers that aid in grading OGs and identifying patients with a better prognosis or response to chemotherapy, proteomic and transcriptomic differential analysis have been carried out between normal brain tissues and AOGs, or AOGs with and without the positive sensitivity against chemotherapy. Proteins and mRNA were extracted from the same brain tissues excised from AOG patients and subjected to the cleavable ICAT, 2D-DIGE, and DNA array analysis. By proteomics analysis, 331 proteins (82; more than 2 times increased, 231;less than 50 % decreased) were identified as tumor specific, and 58 proteins (28; increased, 30;decreased) were identified as specific for tumor with chemotherapy insensitive. In DNA array analysis, 998 transcripts were identified as tumor specific and 149 transcripts (111;increased, 37;decreased) were extracted as specific for tumor with chemotherapy insensitive being only 30% of similarity with the protein expression patterns, increased or decreased, observed in the proteomic analysis. These identified molecules contained not only those reported as tumor specific such as angiogenesis, adhesion, apoptosis, cell cycle related but also novel functional molecules in AOGs. The molecular signal networks of identified proteins were analyzed with KeyMolnet. The meaning of specific proteins in AOGs will be discussed.
