Relative expression of HDAC genes in astrocytomas and normal brain tissue. Class I in purple, class II in orange, and class IV in green. Data obtained by qRT-PCR analysis using Taqman® probes for each gene using the GUS β gene as housekeeping. Standard curves were constructed for each gene by considering at least 3 points in triplicate of 10-fold serial dilution of cDNA in water, starting from 1:10 of a volume of undiluted cDNA transcribed from 1.0 μg of total RNA. The slopes of standard curves ranged from -3.17 to -3.87. Blank and standard controls (calibrators) were run in parallel to verify amplification efficiency within each experiment. To obtain the Ct (cycle) values, we established a threshold of 0.1. *AI, AII and AIII mean astrocytoma grade I, II and III respectively. GBM means glioblastoma.