Abstract
1. Serial determinations of the serum and urine ribonuclease (RNase) activity were made in 157 patients with various diseases including cancer of the digestive organs, benign gastric or duodenal ulcer and calculous biliary disases.
2. In patients with benign gastric or biliary diseases, serum RNase levels were usually within normal limits, and profound surgery of these organs demonstrated little alteration in the concentration of serum ribonuclease.
3. RNase values were often elevated in cancer patients, and the enzyme activity was extremely high in all the cases of those with cancer of the bile duct or gall bladder. Elevations were seen in 36.2 and 27.3 per cent of sera samples from those with carcinoma of the stomach and esophagus, respectively, whereas the incidence and degree of abnormal levels were less marked in those with carcinoma of the pancreas, colon and rectum.
4. RNase activity in patients with neoplastic diseases was usually decreased after :radical operation in comparison with preoperative values.
5. A follow-up investigation was conducted for months into the enzyme level changes among those with advanced malignancies, who were treated conservatively, showing the fluctuation or increased activity of the enzyme during this period in many instances. A rapid and marked increase of RNase activity was frequently noted when, the disease was entering the rapid progressive phase.
