ATF4 and glioblastoma: Under stress conditions, solid tumors like glioblastoma may escape cell death by inducing autophagy in secondary tumor cells through PERK and the activating transcription factor 4 (ATF4), inducing the expression of autophagic genes like ATG5, ATG7, and ULK, along with hemoxygenase-1, an antioxidant enzyme, to prevent anoikis and favor the survival and migration of tumor cells [151].