title: The multiplex bead array approach to identifying serum biomarkers associated with breast cancer.
abstract: BACKGROUND
  Breast cancer is the most common type of cancer seen in women in western countries. Thus, diagnostic modalities sensitive to early-stage breast cancer are needed. Antibody-based array platforms of a data-driven type, which are expected to facilitate more rapid and sensitive detection of novel biomarkers, have emerged as a direct, rapid means for profiling cancer-specific signatures using small samples. In line with this concept, our group constructed an antibody bead array panel for 35 analytes that were selected during the discovery step. This study was aimed at testing the performance of this 35-plex array panel in profiling signatures specific for primary non-metastatic breast cancer and validating its diagnostic utility in this independent population.
  
  
  METHODS
  Thirty-five analytes were selected from more than 50 markers through screening steps using a serum bank consisting of 4,500 samples from various types of cancer. An antibody-bead array of 35 markers was constructed using the Luminex bead array platform. A study population consisting of 98 breast cancer patients and 96 normal subjects was analysed using this panel. Multivariate classification algorithms were used to find discriminating biomarkers and validated with another independent population of 90 breast cancer and 79 healthy controls.
  
  
  RESULTS
  Serum concentrations of epidermal growth factor, soluble CD40-ligand and proapolipoprotein A1 were increased in breast cancer patients. High-molecular-weight-kininogen, apolipoprotein A1, soluble vascular cell adhesion molecule-1, plasminogen activator inhibitor-1, vitamin-D binding protein and vitronectin were decreased in the cancer group. Multivariate classification algorithms distinguished breast cancer patients from the normal population with high accuracy (91.8% with random forest, 91.5% with support vector machine, 87.6% with linear discriminant analysis). Combinatorial markers also detected breast cancer at an early stage with greater sensitivity.
  
  
  CONCLUSIONS
  The current study demonstrated the usefulness of the antibody-bead array approach in finding signatures specific for primary non-metastatic breast cancer and illustrated the potential for early, high sensitivity detection of breast cancer. Further validation is required before array-based technology is used routinely for early detection of breast cancer.
authors.affiliation: Department of Laboratory Medicine and Pathology, The Armed Forces Capital Hospital, Bundnag-Gu, Sungnam City, Gyeonggi-Do, Korea. bkkim3@snu.ac.kr
authors.forename: Byoung Kwon
authors.initials: BK
authors.lastname: Kim
authors.forename: Jong Won
authors.initials: JW
authors.lastname: Lee
authors.forename: Pil Je
authors.initials: PJ
authors.lastname: Park
authors.forename: Yong Sung
authors.initials: YS
authors.lastname: Shin
authors.forename: Won Young
authors.initials: WY
authors.lastname: Lee
authors.forename: Kyung Ae
authors.initials: KA
authors.lastname: Lee
authors.forename: Sena
authors.initials: S
authors.lastname: Ye
authors.forename: Heesun
authors.initials: H
authors.lastname: Hyun
authors.forename: Kyung Nam
authors.initials: KN
authors.lastname: Kang
authors.forename: Donghwa
authors.initials: D
authors.lastname: Yeo
authors.forename: Youngdai
authors.initials: Y
authors.lastname: Kim
authors.forename: Sung Yup
authors.initials: SY
authors.lastname: Ohn
authors.forename: Dong Young
authors.initials: DY
authors.lastname: Noh
authors.forename: Chul Woo
authors.initials: CW
authors.lastname: Kim
mesh_terms: D000465:Algorithms; D014408:Biomarkers, Tumor / Q000097:blood*; D001943:Breast Neoplasms / Q000097:blood* / Q000175:diagnosis*; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D009367:Neoplasm Staging; D011379:Prognosis; D040901:Proteomics
chemical_list: D014408:Biomarkers, Tumor