PSMB7 is a catalytic component of the 20S proteasome core complex exhibiting trypsin-like endopeptidase activity. As part of the 26S proteasome, it mediates ATP-dependent degradation of ubiquitinated proteins essential for protein homeostasis 1. PSMB7 also participates in ubiquitin-independent proteolysis when associated with regulatory particles PA200 or PA28, contributing to processes including antigen presentation via MHC class I peptide generation 1. Clinically, elevated PSMB7 expression associates with poor prognosis across multiple malignancies. In lung adenocarcinoma, high PSMB7 expression correlates with advanced pathological stages, reduced overall and disease-specific survival, and decreased immune cell infiltration 1. Similarly, in breast cancer, PSMB7 overexpression indicates anthracycline resistance and unfavorable survival outcomes; silencing PSMB7 in doxorubicin-resistant cells significantly reduced survival after chemotherapy 2. Conversely, in thyroid cancer, lower PSMB7 expression associates with better prognosis and higher immunotherapy response 3. PSMB7 also functions in oncogenic pathways—mutant LACTB proteins enhance its catalytic activity to reduce wild-type p53 in osteosarcoma 4. These findings position PSMB7 as a promising biomarker for cancer prognosis and potential therapeutic target, though its role varies by cancer type and may involve distinct proteasome-dependent and -independent mechanisms.