Role of HMGB1 in tumors and its targeted therapy.

High-mobility group box 1 (HMGB1), a protein with context-dependent pro- and anti-tumor functions, is expressed in tumor cells, tumor-associated macrophages, tumor-associated neutrophils, cancer-associated fibroblasts, and T cells within the tumor microenvironment. The identity of HMGB1 has undergone a transformation from a nuclear architectural protein to a secreted damage-associated molecular pattern with pivotal roles in inflammation and cancer. The heterogeneity of HMGB1 stems from the diversity of post-translational modifications, proteolytic cleavage and lysis, partial independence of domain functions, differences in source tissues and cells, concentration-dependent effects, spatiotemporal distribution and dynamics, and functional diversity. This review summarizes the roles and molecular mechanisms of nuclear, cytoplasmic, and extracellular HMGB1 derived from different cells in tumor progression, its targeted therapy, and its application value as a biomarker, highlighting the regulation of HMGB1 and the downstream signaling pathways of HMGB1. HMGB1 mainly exerts pro-tumor effects during tumor progression via multiple downstream pathways (MAPK, NF-κB, PI3K/AKT, Wnt, STAT3, etc.), while its subtle induction of cell death and enhancement of the immune response demonstrate moderate anti-tumor effects. HMGB1-mediated immune crosstalk regulates the proliferation, growth, migration, invasion, and chemoresistance of tumors. A comprehensive investigation of the spatiotemporal dynamics of HMGB1 and its underlying molecular regulatory mechanisms using cutting-edge technologies, including single-cell RNA sequencing, spatial transcriptomics, and real-time live-cell imaging, will facilitate the development of precise, mechanism-informed therapeutic interventions. Given the multifaceted challenges posed by tumor heterogeneity, the dual pro- and anti-tumor functions of HMGB1, and the limitations of targeting technologies, HMGB1-targeted strategies hold substantial promise for clinical translation.