In time-dependent experiments, Gills et al. demonstrated phosphorylation of eukaryotic initiation factor 2α (eIF2α), a downstream effector of PERK, and enhanced expression of ER stress-related proteins such as transcription factor 3 (ATF3) and CCAAT enhancer-binding protein homologous protein (CHOP) in nelfinavir-treated lung, breast, and prostate cancer cells [19]. This evidence concerns the gene DDIT3 and prostate carcinoma.