PLEURAL FLUID PSEUDOURIDINE IN MALIGNANT AND BENIGN PLEURAL EFFUSIONS

Pseudouridine in urine and plasma has been proved to be a useful tumou r marker in many malignant conditions. We studied its usefulness in pl eural fluid for distinguishing malignant from non-malignant pleural ef fusions. Pleural fluid pseudouridine concentrations in different group s of patients with pleural effusion (31 malignant, 29 benign, 16 unkno wn, 1 double pathology) was measured and compared. Its usefulness in d istinguishing malignant from non-malignant pleural effusions was analy sed by receiver-operating characteristic (ROC) curve analysis. Pseudou ridine concentrations in the malignant group were significantly higher than the non-malignant group (P<0.017, Bonferroni adjustment) with va lues overlapping extensively at the lower end. The area-under-the curv e (AUG) value in the ROC curve analysis was 0.675 (P<0.05). We conclud e that the pleural fluid pseudouridine is of limited clinical value in distinguishing malignant from non-malignant pleural effusion due to i ts extensive overlap. However, it is useful when the concentration is higher than 65 mu mol/L, which indicates malignancy.