ELK1 and cancer: Figure 2b shows the inferred activity distribution of three TFs identified from our analysis: FOXO1 (Forkhead box O), NFE2L2 and ELK1. FOXO1, a key regulator of cell-cycle progression and apoptosis, was identified as a significant regulator for more than 10% of tumours in BLCA, BRCA and UCEC; its activity showed high variation among tumours for these particular cancers (Fig. 2b, top panel).