title: Methyl-binding domain protein-based DNA isolation from human blood serum combines DNA analyses and serum-autoantibody testing.
abstract: BACKGROUND
  Circulating cell free DNA in serum as well as serum-autoantibodies and the serum proteome have great potential to contribute to early cancer diagnostics via non invasive blood tests. However, most DNA preparation protocols destroy the protein fraction and therefore do not allow subsequent protein analyses. In this study a novel approach based on methyl binding domain protein (MBD) is described to overcome the technical difficulties of combining DNA and protein analysis out of one single serum sample.
  
  
  METHODS
  Serum or plasma samples from 98 control individuals and 54 breast cancer patients were evaluated upon silica membrane- or MBD affinity-based DNA isolation via qPCR targeting potential DNA methylation markers as well as by protein-microarrays for tumor-autoantibody testing.
  
  
  RESULTS
  In control individuals, an average DNA level of 22.8 ± 25.7 ng/ml was detected applying the silica membrane based protocol and 8.5 ± 7.5 ng/ml using the MBD-approach, both values strongly dependent on the serum sample preparation methods used. In contrast to malignant and benign tumor serum samples, cell free DNA concentrations were significantly elevated in sera of metastasizing breast cancer patients. Technical evaluation revealed that serum upon MBD-based DNA isolation is suitable for protein-array analyses when data are consistent to untreated serum samples.
  
  
  CONCLUSIONS
  MBD affinity purification allows DNA isolations under native conditions retaining the protein function, thus for example enabling combined analyses of DNA methylation and autoantigene-profiles from the same serum sample and thereby improving minimal invasive diagnostics.
authors: Molecular Medicine, Austrian Institute of Technology, Muthgasse 11, 1190 Vienna, Austria. Andreas.Weinhaeusel@ait.ac.at.
authors: Matthias
authors: M
authors: Wielscher
authors: Walter
authors: W
authors: Pulverer
authors: Johannes
authors: J
authors: Peham
authors: Manuela
authors: M
authors: Hofner
authors: Christine F
authors: CF
authors: Rappaport
authors: Christian
authors: C
authors: Singer
authors: Christof
authors: C
authors: Jungbauer
authors: Christa
authors: C
authors: Nöhammer
authors: Andreas
authors: A
authors: Weinhäusel