FAS (also known as surface antigen APO1 or CD95) is a member of the tumour-necrosis receptor factor family of death receptors, can induce apoptosis or, conversely, can deliver growth stimulatory signals. It acts as an inducer of both neurite growth in vitro and accelerated recovery after nerve injury in vivo. Fas antigen is expressed and functional on papillary thyroid cancer cells and this may have potential therapeutic significance. The FAS antigen shows structural homology with a number of cell surface receptors, including tumor necrosis factor (TNF) receptors and the low-affinity nerve growth factor receptor (NGFR) and is mapped to 10q24.1. And the FAS and FASL system plays a key role in regulating apoptotic cell death and corruption of this signalling pathway has been shown to participate in immune escape and tumorigenesis.Synonyms: APT1, Apo-1 antigen, FAS1, FASLG receptor, TNFRSF6, Tumor necrosis factor receptor superfamily member 6