Sensitivity and specificity of serum ribonuclease in the diagnosis of pancreatic cancer.

The serum levels of a poly-[C]-specific acid ribonuclease (RNase) found in the pancreas was measured in 40 normal persons and 137 patients with pancreatic cancer, other cancers, obstructive jaundice, acute pancreatitis or chronic pancreatitis. Serum RNase increased by as much as 800 percent above normal in 69 percent of patients with pancreatic cancer. Analysis of the serum isoenzymes of RNase by isoelectric focusing did not reveal any unique RNases produced by the tumours. In contrast, serum RNase rose in only 8 percent of patients with other cancers, 11 percent of other patients with obstructive jaundice and in no patients with chronic pancreatitis. These data suggest that the finding of increased serum RNase is of adjunctive value inthe diagnosis of pancreatic carcinoma and may be particularly helpful in distinguishing it from other causes of biliary obstruction and from chronic pancreatitis.