Apoptosis is essential for removing abnormal cells and maintaining tissue homeostasis, but tumor cells often escape this fate through diverse mechanisms, including downregulation of tumor suppressors (e.g., p53, PTEN) and overexpression of anti-apoptotic factors (e.g., Bcl-2, Bcl-XL, IAPs) [34]. The gene discussed is TP53; the disease is neoplasm.