Copy number aberrations using multicolour fluorescence in situ hybridization (FISH) for prognostication in non-muscle-invasive bladder cancer (NIMBC).

ABSTRACT

OBJECTIVE: To investigate if detection of copy number aberrations of chromosomes 3, 7, 9p21, and 17 using multicolour fluorescence in situ hybridization (FISH) predicts patient outcome in non-muscle-invasive bladder cancer (NMIBC). PATIENTS AND METHODS: In all, 118 bladder wash samples were prospectively collected from patients who underwent transurethral resection of bladder tumour (median age 50.5 years, male/female 91/27, tumour grade 1/2/3 18/52/42, stage pTis/Ta/T1 8/62/42) from 2007 to 2010. The 118 samples were analysed using the UroVysion® kit to detect the copy numbers of chromosomes 3, 7, 9p21, and 17. The variant fraction (VF; the sum of the non-modal copy number fraction of each chromosome) was defined as abnormal when the percentage was ≥16%. The percentage deletion of 9p21 (fraction of null or one copy number of the 9p21 locus) was defined as abnormal when the percentage was ≥12%. Maffezzini risk criteria were also analysed in our cohorts. RESULTS: There was recurrence in 57 (48.3%) patients and disease progression in 12 (10.1%), with a median follow-up of 35.7 months. Multivariate analysis showed that the percentage 9p21 loss (>12%) was an independent prognostic factor for recurrence (P < 0.001, odds ratio [OR] 3.24, 95% confidence interval [CI] 1.85-5.62). For disease progression, tumour grade, positive urine cytology, concurrent carcinoma in situ, and a mean VF of >16% were significant prognostic factors in univariate analysis. In multivariate analysis, a mean VF of >16% was a prognostic factor for disease progression (P = 0.048, OR 6.07, 95% CI 1.02-57.45). CONCLUSIONS: Multicolour-FISH analysis using a commercially available kit could be a powerful tool not only for diagnosis, but also for prognostication in patients with NMIBC.