PTTG2 (pituitary tumor-transforming 2) is a homolog of the securin gene PTTG1 with distinct cellular functions. Unlike PTTG1, PTTG2 lacks securin activity and cannot bind to separase, indicating it does not regulate sister chr4 separation 1. Instead, PTTG2 functions in cell adhesion and epithelial-to-mesenchymal transition (EMT) regulation. Knockdown of PTTG2 reduces cell viability and migration while promoting apoptosis through p53- and p21-dependent pathways 2. PTTG2 modulates EMT by suppressing E-cadherin and promoting vimentin expression 3. Clinically, PTTG2 is significantly overexpressed in multiple cancers including psoriatic epidermis, glioblastoma, hepatocellular carcinoma, esophageal squamous cell carcinoma, and lung adenocarcinoma 4567. In glioblastoma, PTTG2 overexpression promotes proliferation and invasion while inhibiting caspase-3-dependent apoptosis 4. In hepatocellular carcinoma, elevated PTTG2 expression correlates with increased cancer recurrence 5. PTTG2 demonstrates low endogenous expression in normal tissues 2, making it a potential diagnostic and prognostic biomarker. Emerging therapeutic approaches suggest targeting PTTG2 through compounds like Calcitriol 7.