A more comprehensive microarray analysis based on The Cancer Genome Atlas (TCGA) database that included 8 of the 10 most common human malignancies showed that Nrf2 expression was significantly down-regulated in breast (P = 0.015), prostate (P = 0.00065) and kidney (P = 4.2E-19) tumors, with only colon cancer showing up-regulated Nrf2 expression (P = 0.02) when compared to normal tissue (Figure 7A). This evidence concerns the gene NFE2L2 and colonic neoplasm.