title: Changes in glycoprotein expression between primary breast tumour and synchronous lymph node metastases or asynchronous distant metastases.
abstract: BACKGROUND
  Breast cancer is a very heterogeneous disease and some patients are cured by the surgical removal of the primary tumour whilst other patients suffer from metastasis and spreading of the disease, despite adjuvant therapy. A number of prognostic and treatment predictive factors have been identified such as tumour size, oestrogen (ER) and progesterone (PgR) receptor status, human epidermal growth factor receptor type 2 (HER2) status, histological grade, Ki67 and age. Lymph node involvement is also assessed during surgery to determine if the tumour has spread which requires dissection of the axilla and adjuvant treatment. The prognostic and treatment predictive factors assessing the nature of the tumour are all routinely based on the status of the primary tumour.
  
  
  RESULTS
  We have analysed a unique tumour set of fourteen primary breast cancer tumours with matched synchronous axillary lymph node metastases and a set of nine primary tumours with, later developed, matched distant metastases from different sites in the body. We used a pairwise tumour analysis (from the same individual) since the difference between the same tumour-type in different patients was greater. Glycopeptide capture was used in this study to selectively isolate and quantify N-linked glycopeptides from tumours mixtures and the captured glycopeptides were subjected to label-free quantitative tandem mass spectrometry analysis. Differentially expressed proteins between primary tumours and matched lymph node metastasis and distant metastasis were identified. Two of the top hits, ATPIF1 and tubulin β-chain were validated by immunohistochemistry to be differentially regulated.
  
  
  CONCLUSIONS
  We show that the expression of a large number of glycosylated proteins change between primary tumours and matched lymph node metastases and distant metastases, confirming that cancer cells undergo a molecular transformation during the spread to a secondary site. The proteins are part of important pathways such as cell adhesion, migration pathways and immune response giving insight into molecular changes needed for the tumour to spread. The large difference between primary tumours and lymph node and distant metastases also suggest that treatment should be based on the phenotype of the lymph node and distant metastases.
authors.affiliation: Department of Immunotechnology, House 406, Medicon Village, SE-223 81 Lund, Sweden.
authors.forename: Emila
authors.initials: E
authors.lastname: Kurbasic
authors.affiliation: Division of Oncology and Pathology, Department of Clinical Sciences Lund, Lund University, Medicon Village, SE-223 81 Lund, Sweden.
authors.forename: Martin
authors.initials: M
authors.lastname: Sjöström
authors.affiliation: Amber Biosciences AB, Skrivarevägen 9, SE-22657 Lund, Sweden.
authors.forename: Morten
authors.initials: M
authors.lastname: Krogh
authors.affiliation: Division of Oncology and Pathology, Department of Clinical Sciences Lund, Lund University, Medicon Village, SE-223 81 Lund, Sweden.
authors.forename: Elin
authors.initials: E
authors.lastname: Folkesson
authors.affiliation: Division of Oncology and Pathology, Department of Clinical Sciences Lund, Lund University, Medicon Village, SE-223 81 Lund, Sweden ; Department of Pathology, Skåne University Hospital, SE-22185 Lund, Sweden.
authors.forename: Dorthe
authors.initials: D
authors.lastname: Grabau
authors.affiliation: Department of Immunotechnology, House 406, Medicon Village, SE-223 81 Lund, Sweden.
authors.forename: Karin
authors.initials: K
authors.lastname: Hansson
authors.affiliation: Department of Surgery, Clinical sciences, Lund University, SE-22185 Lund, Sweden ; Department of Surgery, Skåne University Hospital, SE-22185 Lund, Sweden.
authors.forename: Lisa
authors.initials: L
authors.lastname: Rydén
authors.affiliation: Department of Immunotechnology, House 406, Medicon Village, SE-223 81 Lund, Sweden.
authors.forename: Sofia
authors.initials: S
authors.lastname: Waldemarson
authors.affiliation: Department of Immunotechnology, House 406, Medicon Village, SE-223 81 Lund, Sweden.
authors.forename: Peter
authors.initials: P
authors.lastname: James
authors.affiliation: Division of Oncology and Pathology, Department of Clinical Sciences Lund, Lund University, Medicon Village, SE-223 81 Lund, Sweden ; Department of Surgery, Skåne University Hospital, SE-22185 Lund, Sweden.
authors.forename: Emma
authors.initials: E
authors.lastname: Niméus
keywords: Biomarkers; Breast cancer; Distant metastases; Glycopeptide capture; Lymph node metastases; Mass spectrometry; Membrane proteins; Secreted proteins