Human SPARC-like 1 (SPARCL1), also known as MAST9 or Hevin, is a member of the SPARC protein family. It is a secreted acidic calcium-binding protein of 664 amino acids that shows 62% identity with SPARC. SPARCL1 is a secreted protein, found in the extracellular matrix. It is expressed at high levels in high endothelial venules (HEV) in lymphoid tissues. SPARCL1 inactivation is a common event in tumors of epithelial origin and levels are down-regulated in a variety of tumors. It may have tumor suppressor activity.