Regenerating islet-derived protein 3-alpha, also known as Regenerating islet-derived protein III-alpha, REG-3-alpha, REG3A, and HIP, is secreted protein which contains one C-type lectin domain. REG3A is constitutively expressed in intestine, and is a pancreatic secretory protein that may be involved in cell proliferation or differentiation. It is overexpressed during the acute phase of pancreatitis and in some patients with chronic pancreatitis. REG3A and REG1A proteins are both involved in liver and pancreatic regeneration and proliferation. REG3A is also a stress protein involved in the control of bacterial proliferation. REG3A is down-regulated in most primary human gastric cancer cells, and might be useful in the diagnosis of gastric cancer. Additionally, REG3A is a target of beta-catenin signaling in Huh7 hepatoma cells. The REG1A and REG3A are downstream targets of the Wnt pathway during liver tumorigenesis.