The textbook "Downregulation of endogenous TRAIL and its effect on cancer cells" by Sara Brittingham provides a comprehensive examination of the role of endogenous TRAIL (Tumor Necrosis Factor-Associated Apoptosis-Inducing Ligand) in cancer biology. It is demonstrated that increased expression of TRAIL is associated with a decreased disease-specific survival rate in cancers that are resistant to TRAIL-induced apoptosis. The author specifically analyzes the neuroblastoma cell line KELLY, which exhibits intrinsic resistance to TRAIL. By investigating the knockdown of endogenous TRAIL, it is shown that this leads to a significant reduction in cell growth and induction of cell death, indicating the function of TRAIL as an intrinsic growth factor. These findings open new perspectives for therapeutic approaches in cancer treatment by identifying endogenous TRAIL as a potential target.