SREBF1 and neoplasm: Mechanistically, EFV administration was shown to affect the tumor cholesterol homeostasis by regulating the activity of the two important transcription factors–liver X receptors (LXRs), for which 24HC is a ligand (Janowski et al., 1996), and sterol regulatory element-binding protein 1 (SREBP1), a sensor of cellular cholesterol and oxysterol levels (Goldstein et al., 2006).