FISH Assay for THE Detection of Bladder Cancer

Abstract

We evaluated the sensitivity and specificity of fluorescence in situ hybridization (FISH) performed on the urine specimens of patients under follow-up for superficial bladder cancer. Thirty-seven patients were enrolled and underwent cystoscopy, urinary cytology or biopsy and FISH examination. Urinary cytology and FISH were evaluated in exfoliated urothelial cells from bladder washings. A mixture of fluorescent labeled probes to the centromere of chromosomes 3, 7 and 17, and locus 9p21 was used to assess urinary cells for chromosomal abnormalities indicative of malignancy. Nine patients (24.3%) showed an abnormal cystoscopy, but only five patients showed transitional cell carcinoma at histology. Eighteen patients (48.6%) showed an abnormal FISH: one patient (2.7%) had a positive cytology, and three patients (8.1%) showed an atypical cytology. Patients with both positive cystoscopy and histological examination had a positive FISH, while only one patient had a positive cytology. Patients with positive cystoscopy and negative histological examination had a negative FISH. Three patients with negative cystoscopy and suspicious cytology had a positive FISH. Ten patients (27%) with both negative cystoscopy and cytology had a positive FISH. The sensitivity of the FISH assay was 100%, 50% for the cytology and 62% for the cystoscopy. The specificity of the FISH assay, cytology and cystoscopy were 66%, 100% and 86%, respectively. The sensitivity of the FISH assay in detecting non-invasive urothelial tumors is worth further studies.