title: Serum DNA hypermethylation in patients with bladder cancer: results of a prospective multicenter study.
abstract: BACKGROUND
  Cell-free serum DNA levels are increased in patients with cancer, and at least partially, these DNA fragments are derived from cancer cells. A few reports indicated that methylated serum DNA in patients with bladder cancer (BCA) is a useful non-invasive biomarker. The purpose of this prospective multicenter study was to validate earlier studies.
  
  
  METHODS
  In total, 227 consecutive participants (non-muscle invasive BCA, n=75; muscle-invasive BCA, n=20; transurethral bladder resection (TURB) without BCA, n=48; benign disease, n=31; healthy individuals, n=53), were recruited for this study. Cell-free serum DNA was isolated and digested with methylation-sensitive restriction-enzymes (Bsh1236I, HpaII and HinP1I) to quantify the amount of methylated (TIMP3, APC, RARB, TIG1, GSTP1, p14, p16, PTGS2 and RASSF1A) DNA fragments.
  
  
  RESULTS
  The amount of methylated DNA was usually small (<10%), and the methylation frequencies varied for different genes (e.g. frequent: TIMP3; moderate: APC, RARB, TIG1; infrequent: p16, PTGS2, p14, RASSF1A, GSTP1). Methylation levels at each gene site and the number of methylated genes were increased in BCA compared to healthy individuals, but were similar in BCA and patients with non-malignant disease. The number of methylated genes allowed for discrimination (62% sensitivity, 89% specificity) of BCA patients from healthy individuals. DNA hypermethylation was not correlated with advanced stage or grade in patients with BCA.
  
  
  CONCLUSIONS
  The detection of hypermethylated DNA in serum allows for discrimination of patients with BCA and healthy individuals, but there is no difference between patients with BCA and those with non-malignant disease, thereby limiting its value as a non-invasive biomarker.
authors.affiliation: Klinik und Poliklinik für Urologie und Kinderurologie, Universitätsklinikum Bonn, Sigmund-Freud-Strasse 25, 53105 Bonn, Germany. stefan.hauser@ukb.uni-bonn.de
authors.forename: Stefan
authors.initials: S
authors.lastname: Hauser
authors.forename: Monika
authors.initials: M
authors.lastname: Kogej
authors.forename: Guido
authors.initials: G
authors.lastname: Fechner
authors.forename: Jochen
authors.initials: J
authors.lastname: VON Pezold
authors.forename: Roland
authors.initials: R
authors.lastname: Vorreuther
authors.forename: Gerd
authors.initials: G
authors.lastname: Lümmen
authors.forename: Stefan C
authors.initials: SC
authors.lastname: Müller
authors.forename: Jörg
authors.initials: J
authors.lastname: Ellinger
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004247:DNA / Q000097:blood*; D019175:DNA Methylation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D001749:Urinary Bladder Neoplasms / Q000097:blood / Q000235:genetics* / Q000473:pathology
chemical_list: D004247:DNA