TWIST1 and cancer: Another pathway involved in EMT and regulated by ROS is the transcription factor hypoxia inducible factor 1-alpha (HIF-1α) (Jiang et al., 2017), which is induced under hypoxic conditions and can stimulate cancer cell EMT by activating EMT-inducing transcription factors such as Twist, Snail and ZEB1/2 (Joseph et al., 2015; Zhang et al., 2015).