Real-time semiquantitative RT-PCR validation of microarray data. Microarray data were validated by RT-PCR for 5 up-regulated (TdT, Sdf1, Spp-1, Lef1, and Ezh2) and 4 down-regulated (c-fos, Slfn1, CD52, and Mmp9) transcripts. The ratios, expressed as fold change for both methods, were generated by comparing expression levels in BM of treated animals (D1, D2, D3, or wt injected) to the basal levels in those of wt animals. Microarrays ratios (n = 4) were plotted against those calculated with real time RT-PCR (n = 3), and Pearson correlation was determined.