In the process of cancer development, Nrf2 expression can be increased by activating oncogenes (such as KRAS) or environmental signals (such as hypoxia) [90, 91], the loss of the negative regulator Kelch-like ECH-associated protein 1 (Keap1) directly activates Nrf2 [89], and elevated levels of ROS prevent the proteasome-mediated degradation of Nrf2. Here, KEAP1 is linked to cancer.