Figure 7

Decreased Nrf2 expression in certain tumors is associated with poor survival. (A) The analysis of 2548 tumors versus 304 normal tissues revealed that Nrf2 (NFE2L2) expression is significantly down-regulated in breast, prostate, and kidney (KIRC) tumors (P values in blue), and significantly up-regulated in colon cancer (P value in red) when compared with normal tissue. However, there are not significant changes in the expression of NFE2L2 when normal tissue is compared with tumors such as bladder, ovarian, lung adenocarcinoma (LUAD), lung squamous cell carcinoma (LUSC), lymphoma and melanoma. Data are presented as log-transformed, and normalized by subtracting the mean across all arrays. The type of tumor and the number of samples analyzed (N) are indicated on the X-axis. These data are taken from TCGA database (https://genome-cancer.ucsc.edu). (B) Low NFE2L2 expression correlated with poorer survival in patients with melanoma (SKCM, P = 0.0341, N = 172), kidney (KIRC, P = 0.0203, N = 481) and prostate (PRAD-GSE21034, P = 0.00279, N = 150) cancers. The Kaplan-Meir survival curves for KIRC, survival in days; PRAD-GSE21034, biochemical recurrence in weeks; and SKCM, survival in days are shown. Samples were categorized as below (lower, black line) or above (higher, red line) median NFE2L2 expression, and the P values were calculated from the log rank (Mantel Cox) test. The hazard ratio for lower NFE2L2 expression were KIRC: 1.46 (1.06-2.02, 95% conf. lim.), SKCM: 1.62 (1.03-2.57, 95% conf. lim.), PRAD-GSE21034: 2.74 (1.375-5.34, 95% conf. lim.). (C) In the same expression datasets we find that NFE2L2 expression is significantly positively correlated with GCLC and GCLM in KIRC, with GCLC, GCLM and NQO1 in PRAD-GSE21034, but with none of these genes in SKCM (as determined using Spearmans rank correlation). The P values are shown for those genes showing a significant correlation.