title: Identification of a beta-casein-like peptide in breast nipple aspirate fluid that is associated with breast cancer.
abstract: OBJECTIVE
  Nipple aspirate fluid was collected prospectively from women scheduled for diagnostic breast surgery in order to determine protein masses associated with breast cancer, subsets of women with a unique proteomic profile and a breast cancer predictive model.
  
  
  METHODS
  Breast nipple aspirate fluid was collected preoperatively in 163 breasts from 125 women and analyzed for changes in cell morphology and by SELDI-TOF mass spectrometry over approximately a 44 kDa range (1.5-45 kDa) using IMAC30, CM10 and Q10 ProteinChips.
  
  
  RESULTS
  Considering all samples, 16 protein masses were associated with the presence of cancer, the most discriminating being 3592, 6570/6580 and 15870 Da. Excluding women with pathologic nipple discharge or those with a papilloma identified an additional protein of 6383 Da. The best cancer detection models included Breast Imaging Reporting and Data System, age, and either the 4262 (best sensitivity: >87%) or 3592 (best specificity: >94%) peak. MALDI-TOF mass spectrometry demonstrated the 3592 peak, which was most discriminating in many of our cancer prediction models, to be a beta-casein-like peptide.
  
  
  CONCLUSIONS
  Differential nipple aspirate fluid proteomic expression exists between women with/without breast cancer. The most discriminating protein identified is a beta-casein-like peptide not previously described. Combining proteomic and clinical information, which are available before surgery, optimizes the prediction of which women have breast cancer.
authors.affiliation: Department of Surgery, University of North Dakota School of Medicine & Health Sciences, 501 N. Columbia Road, Stop 9037, Grand Forks, ND 58201, USA. esauter@medicine.nodak.edu
authors.forename: Edward R
authors.initials: ER
authors.lastname: Sauter
authors.forename: Wade
authors.initials: W
authors.lastname: Davis
authors.forename: Wenyi
authors.initials: W
authors.lastname: Qin
authors.forename: Sarah
authors.initials: S
authors.lastname: Scanlon
authors.forename: Brian
authors.initials: B
authors.lastname: Mooney
authors.forename: Karen
authors.initials: K
authors.lastname: Bromert
authors.forename: William R
authors.initials: WR
authors.lastname: Folk