sentence: Considering that the frequently mutated tumor suppressor and oncogenic pathways in cancers commonly lead to the increased accumulation of ROS ( Szatrowski and Nathan , 1991 ; Lee et al ., 1999 ; Vafa et al ., 2002 ; Nogueira et al ., 2008 ) , the efficient detoxification of ROS is a requisite for cell proliferation.Nrf2 directly activates the essential genes for the glutathione synthesis .