Microarray analysis of Aza-treated U937 cells reveals multiple differentially regulated genes. (A) SAM of a paired analysis between Aza-exposed or nonexposed U937 cells to identify genes that are induced by Aza treatment. The scatter plot indicates the expected as well as the observed variability. Induced and repressed genes are indicated in red and green, respectively. (B) The scatter plot depicts the induced expression of genes (2-fold) by 6 days of Aza treatment of U937 cells. Red dots indicate 274 genes that were significantly induced after 6 days of Aza treatment. (C) Pathway analysis by PANTHER Classification System indicates biochemical pathways to be regulated by Aza treatment of U937 cells for all differentially expressed genes or for genes that were 2-fold induced (n = 274). (D) Relative levels of mRNA expression of transcripts identified from microarray analysis. Real-time RT-PCR was performed using mRNA from U937 cells treated with Aza for the indicated time. Expression levels for each gene were normalized to GAPDH levels.