TESC (tescalcin) is an EF-hand calcium-binding protein that functions as a multifaceted regulator of cellular processes with significant oncogenic properties. The protein serves as an integral cofactor in cell pH regulation by controlling Na+/H+ exchange activity and promotes hematopoietic stem cell differentiation toward megakaryocytic and granulocytic lineages through ERK-dependent mechanisms. In cancer contexts, TESC demonstrates oncogenic functions across multiple malignancies. It is overexpressed in colorectal cancer where it activates Akt-dependent NF-κB signaling pathways to promote cell survival 1. In thyroid cancers, TESC promotes malignant progression by activating ERK signaling, reducing NIS expression, and weakening radioiodine uptake, contributing to treatment resistance 2. The protein also facilitates epithelial-mesenchymal transition (EMT) in papillary thyroid microcarcinoma through FOS/ERK signaling 3 and in esophageal squamous carcinoma via AKT pathway activation 4. TESC expression is epigenetically regulated through promoter methylation, with hypermethylation leading to decreased expression in gastric cancer cells 5. Additionally, a genetic variant (rs7294919) regulating TESC affects hippocampal structure in major depressive disorder 6, suggesting neurobiological functions beyond its established roles in cell differentiation and oncogenesis.