Non-specificity of elevated serum ribonuclease as a pancreatic tumour marker.

Differences in heart stability of human pancreatic ribonuclease (cRNase) and serum ribonuclease were abolished by aprotinin, suggesting that the pancreatic enzyme was similar to the serum enzyme, but was being destroyed by proteases. Serum ribonuclease levels in normal subjects correlated with age but were unaffected by meal ingestion. Serum ribonuclease was not found to be useful in the detection of pancreatic cancer and was more frequently abnormal in patients with other solid tumours or renal failure.