Malignant brain tumours associated with adenylate kinase in cerebrospinal fluid.

Adenylate-kinase activity was measured in cerebrospinal fluid (C.S.F.) from 35 healthy control subjects and 11 patients with brain tumours, of which 9 were malignant and 2 benign. No adenylate kinase could be detected in C.S.F. from the controls or from the patients with benign brain tumours. The enzyme was consistently found in C.S.F. from patients with malignant brain tumours.