SAA2 and neoplasm: Murine SAA is encoded by a family of three inducible genes, Saa1, Saa2, and Saa3, and a constitutively expressed Saa4. Although the inducible isoforms of SAA are synthesized mainly in the liver, they are also produced extrahepatically by a variety of tissues and cells, including macrophages, adipocytes, synovial cells, and tumor cells [17–21].