PPP1R14B (protein phosphatase 1 regulatory inhibitor subunit 14B) is a phosphorylation-dependent inhibitor of protein phosphatase 1 (PP1) 1 with potent regulatory activity when phosphorylated [UniProt]. Under physiological conditions, PPP1R14B maintains cellular homeostasis through selective PP1 regulation 1; however, its pathological upregulation promotes oncogenic signaling across multiple cancer types 1. Mechanistically, PPP1R14B stabilizes oncoproteins through PP1-dependent dephosphorylation. In triple-negative breast cancer, PPP1R14B maintains STMN1 phosphorylation and stability, promoting paclitaxel resistance and metastasis 2. In prostate cancer, PPP1R14B activates the JAK2/STAT3/AR pathway, reducing enzalutamide sensitivity 3. In hepatocellular carcinoma, PPP1R14B stabilizes RPS6KA1 protein, activating AKT/NF-κB signaling 4. In cervical and endometrial cancers, PPP1R14B promotes proliferation through Akt pathway activation 5. Clinically, PPP1R14B is consistently upregulated across multiple cancer types and independently predicts poor prognosis and reduced survival 6 7. High expression correlates with reduced CD8+ T cell infiltration, suggesting immunosuppressive functions 8. PPP1R14B represents a pan-cancer biomarker and promising therapeutic target for precision oncology approaches 1.