Urinary cytology and competitive reverse transcriptase-polymerase chain reaction analysis of a specific CD44 variant to detect and monitor bladder cancer.

Abstract

Recently a novel molecular approach, CD44 variant exon (v)8-10/CD44 v10 competitive reverse transcription-polymerase chain reaction (RT-PCR), was developed. CD44 competitive RT-PCR can detect a sparse population of cancer cells over expressing CD44 v8-10 among a much larger population of nonneoplastic cells in body fluids, that is pleural effusion and urine, by the measurement of transcriptional CD44 v8-10 relative to CD44 v10. The use of the CD44 competitive RT-PCR assay to diagnose and monitor bladder cancer was compared to urinary cytology. Spontaneously voided urine samples from 71 patients with bladder cancer and 50 with benign urological diseases were analyzed by CD44 competitive RT-PCR and conventional urinary cytology. Urine samples from 24 patients with completely resected bladder tumors also were analyzed. The CD44 competitive RT-PCR assay and urinary cytology revealed a sensitivity of 77 and 58%, and a specificity of 100 and 98%, respectively. Furthermore, combining the results of the 2 methods increased sensitivity to 90%. Urine samples from patients with bladder cancer following curative surgery were correctly diagnosed in 96% with the CD44 competitive RT-PCR assay compared to 83% with urinary cytology. The CD44 competitive RT-PCR assay is a useful, noninvasive method to diagnose and monitor bladder cancer. The assay could be an important adjunct to urinary cytology to detect exfoliated bladder cancer cells in urine.