KRAS and cancer: Mechanisms by which the Nrf2 signaling pathway is constitutively activated in several types of cancer include (i) somatic mutations of Keap1 disrupting the binding capacity to Nrf2, (ii) epigenetic silencing of Keap1 and (iii) transcriptional induction of Nrf2 by oncogenes such as K-ras, B-raf or c-myc [46] (Fig. 3).