Increased angiogenin expression in obstructive chronic pancreatitis surrounding pancreatic cancer but not in pure chronic pancreatitis.

We previously demonstrated the increased expression of angiogenin (ANG) in pancreatic cancer and its relation to cancer aggressiveness; however, the expression patterns and the roles of angiogenin in chronic pancreatitis are still unknown. We investigated the expression of ANG both in the tissues and in the sera of chronic pancreatitis patients (pure chronic pancreatitis) by using in situ hybridization, Western blot analysis, and enzyme-linked immunosorbent assay. In situ hybridization revealed no detectable ANG messenger RNA (mRNA) signals in all tissues of pure chronic pancreatitis and normal pancreas. Only a small amount of protein band expression was obtained in all of the protein lysates of pure chronic pancreatitis and normal pancreas. Accordingly, there was no significant difference between the mean serum ANG concentration of chronic pancreatitis patients (352.1+/-72.5 ng/ml) and that of healthy volunteers (357.6+/-45.2 ng/ml). By contrast, acinar cells and interstitial fibroblasts in the tissues surrounding pancreatic cancer showed increased ANG mRNA expression. Strong protein band expression was obtained in the protein lysates of pancreatic cancer surrounding tissue, and mean serum ANG concentration was increased in pancreatic cancer patients. These findings suggest that ANG expression is increased in pancreatic cancer surrounding tissue but is not increased in pure chronic pancreatitis, and that ANG is potentially involved in the pancreatic cancer microenvironment rather than the establishment of pure chronic pancreatitis.