From Genome Guardian to Immune Modulator: The Expanding Roles of Tumor Suppressor p53

p53 is a key tumor suppressor, and mutations in the p53 gene occur in more than half of all human cancers. p53, which is under tight and complex regulation in cells, functions primarily as a transcription factor regulating genes involved in many cellular processes, including cell cycle arrest, apoptosis, senescence, ferroptosis, and metabolism, thereby maintaining genomic integrity and preventing tumorigenesis. While the cell-intrinsic functions of p53, which contribute to its tumor-suppressive activity, have been extensively studied, it is now clear that p53 also plays an important role in immune regulation, a connection first observed when p53 was identified as a cellular protein interacting with viral antigens. Growing evidence shows that p53 modulates both innate and adaptive immunity by regulating cytokine production, antigen presentation, and the functions of immune cells, thereby contributing to host defense against infections, inflammatory responses, and antitumor immunity. In this review, we summarize and discuss the multifaceted roles of p53 and its signaling in regulating immune functions and their implications in human diseases, particularly cancer. A better understanding of the immune-related functions of p53 is crucial for advancing cancer treatment and broadening insights into immunity and disease.