Validation of the microarray results by qPCR. (A) Scatter plot of the differential gene expression in response to imatinib (blue) and omacetaxine (red). Both axes show log-transformed differential gene expression. Results are for all five genes that were assayed by microarray and qPCR. Since qPCR used HPRT1 as the normalizer gene, the microarray based results are shown after correction for HPRT1 expression. (B) Mean differential gene expression for the five selected genes by qPCR (left panel) and microarray (right panel) in response to imatinib (blue bars) and omacetaxine (red bars) treatment. The bars represent log-transformed differential gene expression values.