Interphase fluorescence in-situ hybridization in the diagnosis of bladder cancer

Interphase FISH is a technique that uses fluorescent molecules to detect chromosomes or specific regions of DNA. It is a rapid and powerful technique for detection of cytogenetic abnormalities in malignant cells independent of their cell cycle status. Using variety of pericentromeric and locus-specific probes, numerical chromosomal changes (aneusomy) as well as loss or gain/amplification of specific genetic regions can be detected in clinical samples. Numerous studies have identified genetic alterations at the DNA level, occurring in the pathogenesis of variety of human neoplasms including bladder cancer, some of which can be used for detection, prognosis, and as intermediate endpoints for evaluating the response to therapy. Recently, sensitivity and specificity of a multicolor FISH assay consisting of four probes (3, 7, 17 and 9p21) was analyzed in several prospective and retrospective studies. The data suggest that this method applicable to voided urine specimens may allow safe extension of the interval between cystoscopies in routine surveillance of patients with transitional cell carcinoma of the bladder. FISH analysis of cells isolated from bladder washings or voided urine is also holding promise for monitoring of treatment outcome and predicting recurrence and progression of the disease. Therefore, this technique can be an important aid in the efforts to reduce mortality from transitional cell carcinoma of the bladder, since it increases our ability to prevent progression to incurable muscle invasive disease.