Abstract: Stanniocalcin (STC) was first found as a calcium- and phosphate-regulating hormone produced in bony fish by the corpuscles of Stannius. In mammals, the homolog STC-1 displays a relative high amino acid sequence identity (nearly 50%) with fish STC, and STC-2 has a lower identity (nearly 35%) with STC-1 and fish STC. Both STC-1 and STC-2 are expressed in a variety of tissues. The functions of STC have not been understood. But some findings have been reported on their cellular localization, gene structure, and expression in different physiological and pathological conditions, which will be clues in elucidating the functions of STC in mammals. Moreover, STC-1 and STC-2 are expressed in many tumor cell lines, suggesting other biological functions of STC in mammals other than
mineral metabolism.

Key words: Stanniocalcin, Tumor, Cell proliferation, Tumor microenvironmemt