NFE2L2 and cancer: In normal healthy cells, Nrf2 assists in the maintenance of cellular redox homeostasis via the elimination of ROS and chemical or physical carcinogens, while in several types of cancer, the overexpression of Nrf2 enables the cancer cells to adapt to a hostile microenvironment, whereby they can become resistant to elevated endogenous ROS levels and to chemotherapeutic agents and radiotherapy [29,36,37,39].