There are a number of ELISA Kits available for the measurement of GREG, another term for the human protein, bone marrow stromal cell antigen 2. Other synonyms may include: bone marrow stromal antigen 2, BST-2, HM1.24 antigen, NPC-A-7, and BST-2. It is encoded by the BST2 gene to yield a protein 180 amino acids in length and 19.8 kDa in size. However, there are up to 2 reported isoforms. The protein is categorized into the Tetherin family. Versions of GREG are present in other organisms, including: Mouse, Rat.