PSMD7 (proteasome 26S subunit, non-ATPase 7) is a core component of the 26S proteasome that functions as a deubiquitinating enzyme, regulating protein stability through the ubiquitin-proteasome system 12. As part of the proteasome regulatory particle lid subcomplex, PSMD7 removes ubiquitin modifications from target proteins, thereby preventing their degradation and stabilizing key cellular proteins 13. The enzyme demonstrates metal-dependent deubiquitinase activity and binds to H3K4me3-marked promoters to regulate gene expression 4. PSMD7 plays critical roles in cell cycle progression, apoptosis regulation, and DNA damage repair by stabilizing proteins such as RAD23B in gastric cancer and RAB1A in bladder cancer 13. Disease relevance is significant, as PSMD7 is consistently overexpressed across multiple cancer types including gastric, breast, bladder, and head and neck squamous cell carcinomas, where high expression correlates with poor prognosis, increased tumor progression, and chemotherapy resistance 1235. Clinically, PSMD7 serves as an independent prognostic indicator and potential therapeutic target, with knockdown studies demonstrating reduced tumor growth and enhanced sensitivity to conventional therapies 123.