IAPP (amylin) is a peptide hormone secreted by pancreatic B-cells in concert with insulin. It is functionally involved in reducing insulin demand and also safeguarding against post-prandial spikes in blood glucose levels through glycemic regulation. Aggregations of IAPP propeptide (proIAPP) are associated with loss of islet B-cells and impairment of the pancreas in Type 2 diabetes. In immunohistochemistry, IAPP antibodies can be used as a positive marker for identifying insulinomas of the pancreas. In normal tissue, amylin stains the cytoplasm of beta cells and roughly 50% of islet and insulin cells in the pancreas. References: Diabet Med. 2004. 21 (11): 1204–12, PMID: 15498087; Diabetes. 2005. 54 (7): 2117–25, PMID 15983213; Islets 2011;3:344, PMID: 21983096