Sandwich ELISA quantitative detection kit for Mouse Soluble FAS in cell culture supernates, serum and plasma (heparin, EDTA, citrate).Fas, also known as APO-1, CD95 and TNFRSF6, is a member of the nerve growth factor (NGF)/tumour necrosis factor (TNF) receptor superfamily and mediates apoptosis.1 The nucleotide sequence of the cDNAs reveales that the molecule coding for the Fas antigen determinant is a 319 amino acid polypeptide with a single transmembrane domain. The extracellular domain is rich in cysteine residue, and shows a similarity to that of human tumor necrosis factor receptors, human nerve growth factor receptor, and human B cell antigen CD40.2 The APO-1 antigen as defined by the mouse monoclonal antibody anti-APO-1 is previously found to be expressed on the cell surface of activated human T and B lymphocytes and a variety of malignant human lymphoid cell lines. The APO-1 antigen is found to be a membrane glycoprotein of 48kD.3 Fas antigen is expressed and functional on papillary thyroid cancer cells and this may have potential therapeutic significance.4 Fas can play a role as an inducer of both neurite growth in vitro and accelerates recovery after nerve injury in vivo.5