Conserved expression of hepatocyte growth factor activator inhibitor type-2/placental bikunin in human colorectal carcinomas

Hepatocyte growth factor activator inhibitor type 2 (HAI-2) was recently id entified as a potent inhibitor of hepatocyte growth factor activator. It wa s also independently reported as placental bikunin (PB) and as a protein ov er-expressed in pancreatic cancer. The expression of HAI-2/PB was analyzed in human normal colon mucosa, adenomas, and carcinomas. HAI-2/PB mRNA was c onsistently expressed in the colorectal mucosa. The expression was conserve d in the neoplastic colorectal mucosa, and no relationship was found betwee n HAI-2/PB mRNA levels and tumor stages. Moreover, 13 out of 14 colorectal carcinoma cell lines expressed HAI-2/PB mRNA. Immunohistochemically, HAI-2/ PB proteins were predominantly stained beneath the apical surface of normal enterocytes. In tumor tissues, rather disarranged intracytoplasmic granula r staining was observed. The HAI-2/PB immunoreactivity was well conserved i n the colonic adenoma-carcinoma sequence, and this protein may have importa nt unknown function in the intestinal mucosa. (C) 2000 Elsevier Science Ire land Ltd. All rights reserved.