Calcium-binding protein S100P and cancer: mechanisms and clinical relevance.

S100P is a 95-amino-acid protein and a member of the S100 family. It was first purified from placenta. The promoter area of S100P has binding sites for SMAD, STAT/CREB and SP/KLF, key regulatory elements participating in transcriptional activation of the S100P gene. Increased levels of S100P have been observed in multiple tumor cell lines and breast, pancreas, lung and ovary carcinomas. S100P has been shown to mediate tumor growth, metastasis and invasion through the binding of Ca(2+) ions, receptor for advanced glycation end products, cytoskeletal protein ezrin, calcyclin-binding protein/Siah-1-interacting protein and cathepsin D. S100P could potentially serve as diagnostic marker, prognostic/predictive indicator and therapy target for different carcinomas.