Quantitative real-time PCR validation of microarray gene expression data. Comparison of gene expression levels of 5 representative genes located on chromosomes 1 and 17. A. Microarray gene expression data in 49 NBT from MSKCC. Gene expression data were log-transformed and normalized to TBP expression levels; B. Q-PCR gene transcript quantification in 21 NBTs from MSKCC; C. Q-PCR gene transcript quantification in 25 NBTs from Spanish institutions. Results were compared by two-tailed independent-sample t test using SPSS v.14.0 for Windows (SPSS, Chicago, IL). Expression data are shown as box plots (SPSS v.14.0).