title: Chromosomal alterations in exfoliated urothelial cells from bladder cancer cases and healthy men: a prospective screening study.
abstract: BACKGROUND
  Chromosomal instability in exfoliated urothelial cells has been associated with the development of bladder cancer. Here, we analyzed the accumulation of copy number variations (CNVs) using fluorescence in situ hybridization in cancer cases and explored factors associated with the detection of CNVs in tumor-free men.
  
  
  METHODS
  The prospective UroScreen study was designed to investigate the performance of UroVysion™ and other tumor tests for the early detection of bladder cancer in chemical workers from 2003-2010. We analyzed a database compiling CNVs of chromosomes 3, 7, and 17 and at 9p21 that were detected in 191,434 exfoliated urothelial cells from 1,595 men. We assessed the accumulation of CNVs in 1,400 cells isolated from serial samples that were collected from 18 cancer cases up to the time of diagnosis. A generalized estimating equation model was applied to evaluate the influence of age, smoking, and urine status on CNVs in cells from tumor-free men.
  
  
  RESULTS
  Tetrasomy of chromosomes 3, 7 and 17, and DNA loss at 9p21 were the most frequently observed forms of CNV. In bladder cancer cases, we observed an accumulation of CNVs that started approximately three years before diagnosis. During the year prior to diagnosis, cells from men with high-grade bladder cancer accumulated more CNVs than those obtained from cases with low-grade cancer (CNV < 2: 7.5% vs. 1.1%, CNV > 2: 16-17% vs. 9-11%). About 1% of cells from tumor-free men showed polysomy of chromosomes 3, 7, or 17 or DNA loss at 9p21. Men aged ≥50 years had 1.3-fold more cells with CNVs than younger men; however, we observed no further age-related accumulation of CNVs in tumor-free men. Significantly more cells with CNVs were detected in samples with low creatinine concentrations.
  
  
  CONCLUSIONS
  We found an accumulation of CNVs during the development of bladder cancer starting three years before diagnosis, with more altered cells identified in high-grade tumors. Also, a small fraction of cells with CNVs were exfoliated into urine of tumor-free men, mainly exhibiting tetraploidy or DNA loss at 9p21. Whether these cells are preferentially cleared from the urothelium or are artifacts needs further exploration.
authors.forename: Nadine
authors.initials: N
authors.lastname: Bonberg
authors.affiliation: Institute for Prevention and Occupational Medicine of the German Social Accident Insurance, Institute of the Ruhr-Universität Bochum (IPA), Buerkle-de-la-Camp-Platz 1, 44789 Bochum, Germany. pesch@ipa-dguv.de.
authors.forename: Beate
authors.initials: B
authors.lastname: Pesch
authors.forename: Thomas
authors.initials: T
authors.lastname: Behrens
authors.forename: Georg
authors.initials: G
authors.lastname: Johnen
authors.forename: Dirk
authors.initials: D
authors.lastname: Taeger
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Gawrych
authors.forename: Christian
authors.initials: C
authors.lastname: Schwentner
authors.forename: Harald
authors.initials: H
authors.lastname: Wellhäußer
authors.forename: Matthias
authors.initials: M
authors.lastname: Kluckert
authors.forename: Gabriele
authors.initials: G
authors.lastname: Leng
authors.forename: Michael
authors.initials: M
authors.lastname: Nasterlack
authors.forename: Christoph
authors.initials: C
authors.lastname: Oberlinner
authors.forename: Arnulf
authors.initials: A
authors.lastname: Stenzl
authors.forename: Thomas
authors.initials: T
authors.lastname: Brüning
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002869:Chromosome Aberrations; D002877:Chromosomes, Human; D056915:DNA Copy Number Variations; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D058670:Tetrasomy; D001749:Urinary Bladder Neoplasms / Q000235:genetics* / Q000473:pathology; D019459:Urothelium / Q000378:metabolism* / Q000473:pathology