Follicular Dendritic Cell Secreted Protein （FDCSP） is a small secreted protein which is found in follicular dendritic cells. The FDCSP protein specifically binds to activated B cells， and serves as a regulator of antibody responses. In addition， FDCSP is assumed to contribute to tumor metastases by promoting cancer cell migration and invasion. FDCSP binds to the surface of B-lymphoma cells， but not T-lymphoma cells， which is consistent with a function as a secreted mediator acting upon B-cells. FDCSP is abundantly expressed in the tonsil， lymph node， and tracheam， having a strong expression in the prostate and a lower expression in the thyroid， stomach and colon.
