title: High-performance metabolic marker assessment in breast cancer tissue by mass spectrometry.
abstract: BACKGROUND
  The identification of reliable markers for diagnosis of breast cancer has been thoroughly addressed by metabolic profiling using nuclear magnetic resonance (NMR) spectroscopy or imaging. Several clear diagnostic indicators have emerged using either in vitro analysis of tissue extracts, ex vivo analysis of biopsies or in vivo direct spectral observations. Most of the breast cancer characteristic metabolites could be assayed by mass spectrometry (MS) to exploit the superior sensitivity of this technique and therefore reduce the traumatic impact of current biopsy procedures.
  
  
  METHODS
  Following extraction, aqueous metabolite mixtures were obtained that were submitted to liquid-chromatography, electrospray-ionization, mass spectrometry (LC/ESI-MS) analysis to estimate the content of choline (Cho) and its phosphorylated derivatives, phosphocholine (PCho) and glycerophosphocholine (GPCho). The determinations were performed using 10 samples from breast tissue biopsies, surgical specimens and one single sample of a hepatic metastasis. In addition, some measurements were also repeated using high-resolution ¹H NMR spectroscopy to complement the mass spectrometry results.
  
  
  RESULTS
  The contents of Cho, PCho and GPCho in breast tissue extracts were estimated by LC/ESI-MS based on standard compound calibration curves. Sharply increased ratios of phosphorylated-to-unphosphorylated metabolites, PCho/ Cho and (PCho+GPCho)/Cho, were observed in all tumor samples, although without discrimination between benign and malignant lesions, contrary to samples from healthy individuals and from those with fibrocystic disease.
  
  
  CONCLUSIONS
  The assessment of breast cancer markers by LC/ESI-MS is feasible and diagnostically valuable. In addition to high sensitivity, the approach also shows a resolution advantage for assaying choline derivatives compared to NMR, and could complement the latter.
authors.affiliation: Dipartimento di Scienze e Tecnologie Biomediche, Università di Udine, Udine, Italy.
authors.forename: Maria Chiara
authors.initials: MC
authors.lastname: Mimmi
authors.forename: Paola
authors.initials: P
authors.lastname: Picotti
authors.forename: Alessandra
authors.initials: A
authors.lastname: Corazza
authors.forename: Elena
authors.initials: E
authors.lastname: Betto
authors.forename: Carlo E
authors.initials: CE
authors.lastname: Pucillo
authors.forename: Laura
authors.initials: L
authors.lastname: Cesaratto
authors.forename: Carla
authors.initials: C
authors.lastname: Cedolini
authors.forename: Viviana
authors.initials: V
authors.lastname: Londero
authors.forename: Chiara
authors.initials: C
authors.lastname: Zuiani
authors.forename: Massimo
authors.initials: M
authors.lastname: Bazzocchi
authors.forename: Gennaro
authors.initials: G
authors.lastname: Esposito
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis* / Q000302:isolation & purification; D044963:Biopsy, Fine-Needle; D001943:Breast Neoplasms / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology*; D002853:Chromatography, Liquid; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry / Q000379:methods* / Q000592:standards; D012015:Reference Standards
chemical_list: D014408:Biomarkers, Tumor