Lymphatic vessel endothelial hyaluronan receptor 1 immunocytochemical staining for pancreatic islets and pancreatic endocrine tumors.

Immunocytochemical staining for lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1) is able to recognize lymphatic vessel endothelium and pancreatic endocrine cells (PETs). Pancreatic endocrine tumors were studied for LYVE-1 immunocytochemical staining compared with normal pancreatic islets to detect possible presence of LYVE-1 in PETs. Twenty-five cases of primary and metastatic PETs were immunocytochemically stained for LYVE-1, including insulinomas, glucagonomas, somatostatinoma, pancreatic polypeptidomas, gastrinomas, and nonfunctioning tumors. With routinely formalin-fixed and paraffin-embedded tissues, LYVE-1 immunostaining was performed with polyclonal goat antihuman LYVE-1. All normal pancreatic islet cells were positive for LYVE-1, whereas 2 cases of 25 PETs, 1 each of gastrinoma and nonfunctioning tumor, were positive for LYVE-1, retaining immunocytochemical reactivity of islet cells. Normal pancreatic islets were positive for LYVE-1, whereas only 2 of 25 PETs were positive, suggesting that most PETs lost LYVE-1 or contained below detectable levels of LYVE-1. The presence of LYVE-1 in pancreatic islets and in some PETs may suggest structure-function relationship of LYVE-1/lymphatic vessel in hormone synthesis and secretion.