Quantitative profiling of genes associated with cancer pathways in brain tumors.

Background: Brain tumors are a heterogeneous group of malignancies characterized by inter- and intratumoral heterogeneity. Among them, the most aggressive and, despite advances in medicine, still incurable remains glioblastoma. One of the reasons is the high recurrence rate of the disease and resistance to temozolomide, a golden standard in chemotherapy of brain tumors. Therefore, mapping the pathways responsible for tumorigenesis at the transcriptional level may help to determine the causes and aggressive behavior among different glial tumors.

Patients and methods: Biopsies from patients with astrocytoma (N = 6), glioblastoma (N = 22), and meningioma (N = 14) were included in the sample set. A control group consisted of RNA isolated from healthy human brain (N = 3). The reverse-transcribed cDNAs were analyzed using the Human Cancer PathwayFinder™ real-time PCR Array in a 96-well format. The expression of 84 genes belonging to 9 signaling pathways (angiogenesis, apoptosis, cell cycle and senescence, DNA damage and repair, epithelial-to-mesenchymal transition, hypoxia, overall metabolism, and telomere dynamics) was determined for each sample.

Results: By determining the relative expression of selected genes, we characterized the transcriptomic profile of individual brain malignancies in the context of signaling pathways involved in tumorigenesis. We observed deregulation in 50, 52.4 and 53.6% % of the genes in glioblastomas, meningiomas and astrocytomas, respectively. The most pronounced changes with statistical significance compared to control were observed in the genes associated with epithelial-to-mesenchymal transition (CDH2, FOXC2, GSC, SNAI2, and SOX10), cellular senescence (BMI1, ETS2, MAP2K1, and SOD1), DNA repair (DDB2, ERCC3, GADD45G, and LIG4), and dynamic of telomeres (TEP1, TERF2IP, TNKS, and TNKS2).

Conclusion: Based on the obtained data, we can conclude that individual diagnoses differ in transcriptomic profile. An individual molecular approach is therefore necessary in order to provide comprehensive and targeted therapy on multiple metabolic pathways in the diagnosis of brain tumors.