STANDARDIZATION OF ASSAY FOR CYTOKERATIN RELATED TUMOR-MARKER CYFRA21.1 IN URINE SAMPLES

The determination of tumor markers in urine samples has been proposed as an effective diagnostic tool in bladder cancer. The aim of the pres ent investigation was to validate in urine samples the assay of the CY FRA21.1 cytokeratin-related marker, the serum concentrations of which showed promising diagnostic utility in patients with bladder cancer. F irst-voided urine samples were collected from patients with different malignancies. CYFRA21.1 was assayed with a commercially available enzy me immunoassay (Boehringer Mannheim). Different centrifugation pattern s, the use of different buffers and nonionic detergents, and pH variat ions were evaluated. We demonstrated that: (a) cells and cell debris c ontain a large amount of CYFRA21.1 and must be eliminated by centrifug ation; (b) storage at -20 degrees C causes amorphous precipitate, whic h may aspecifically bind CYFRA21.1; (c) the latter behavior may be pre vented by diluting fresh urine samples with phosphate buffer with noni onic detergent added; (d) pH variations within the range 4.9-8.2 do no t significantly affect CYFRA21.1 assay results, Provided that samples are diluted with buffer containing nonionic detergent, the CYFRA21.1 a ssay showed good precision and accuracy characteristic in urine sample s. We therefore propose a standard protocol for the collection of urin e samples for CYFRA21.1 assay. In a preliminary clinical evaluation, C YFRA21.11 concentrations in 16 patients with primary bladder cancer we re higher than in healthy subjects, In the urine collected in the foll ow-up of patients treated for bladder cancer, CYFRA21.1 tended to be h igher in relapsed patients than in those without evidence of disease. These preliminary data induced us to extend the clinical trial to esta blish the actual role of this assay in routine use.