Serum ribonuclease activity in cancer patients

Abstract

A study was made of the levels of RNase in human serum, using 2 independently collected banks of samples from Scripps Clinic and Research Foundation [La Jolla, California, USA] and the Mayo Clinic [Rochester, Minnesota, USA], each bank representing more than 100 individuals. These serum samples originated from a cross-section of normal individuals, smokers, patients with benign tumors and patients with a variety of neoplasms. Elevated levels of serum RNase occurred in 68% of the samples from individuals with malignant disease. Elevated levels also occurred in 24% of the samples from individuals with benign tumors and 38% of the smoker controls from the Mayo Clinic serum bank. Using ion-exchange chromatography, pooled sera from normal individuals and cancer patients were fractionated by differential salt elution. Each pool showed 2 distinct peaks of RNase activity, and both peaks were elevated to the same degree in the cancer serum pools. Similar results were obtained after thin-layer gel-isoelectric focusing of normal and cancer sera. No new species of RNase could be detected in the sera of patients with malignant diseases. The results suggested a generalized nonspecific increase in serum RNase in these patients which could be used as a diagnostic test.