Urinary excretion of pseudouridine in patients with brain tumours.

Elevated urinary levels of modified nucleosides, especially pseudouridine (psi), have been observed in patients with a variety of malignant neoplasms. In this report, the urinary psi levels were estimated by high performance liquid chromatography in 93 patients with brain tumours and in 40 age and sex matched controls. The psi levels were found to be excreted in equal amounts in the control and the tumour groups. There was no significant difference in psi when patients with malignant diseases were compared with those with benign tumours. Following therapy, the psi levels remained unchanged when compared to the controls and their preoperative values. It is concluded that urinary psi concentration is not a useful marker for brain tumours.