title: Identification of potential serum biomarkers for breast cancer using a functional proteomics technology.
abstract: BACKGROUND
  Cancer is a genetic disease; its development and metastasis depend on the function of many proteins. Human serum contains thousands of proteins; it is a window for the homeostasis of individual's health. Many of the proteins found in the human serum could be potential biomarkers for cancer early detection and drug efficacy evaluation.
  
  
  METHODS
  In this study, a functional proteomics technology was used to systematically monitor metabolic enzyme and protease activities from resolved serum proteins produced by a modified 2-D gel separation and subsequent Protein Elution Plate, a method collectively called PEP. All the experiments were repeated at least twice to ensure the validity of the findings.
  
  
  RESULTS
  For the first time, significant differences were found between breast cancer patient serum and normal serum in two families of enzymes known to be involved in cancer development and metastasis: metabolic enzymes and proteases. Multiple enzyme species were identified in the serum assayed directly or after enrichment. Both qualitative and quantitative differences in the metabolic enzyme and protease activity were detected between breast cancer patient and control group, providing excellent biomarker candidates for breast cancer diagnosis and drug development.
  
  
  CONCLUSIONS
  This study identified several potential functional protein biomarkers from breast cancer patient serum. It also demonstrated that the functional proteomics technology, PEP, can be applied to the analysis of any functional proteins in human serum which contains thousands of proteins. The study indicated that the functional domain of the human serum could be unlocked with the PEP technology, pointing to a novel alternative for the development of diagnosis biomarkers for breast cancer and other diseases.
authors.affiliation: Department of Biology, Vanderbilt University, Nashville, TN USA.
authors.forename: David L
authors.initials: DL
authors.lastname: Wang
authors.affiliation: Zibo Central Hospital, Zibo, China.
authors.forename: Chuanguang
authors.initials: C
authors.lastname: Xiao
authors.affiliation: Array Bridge Inc., 4320 Forest Park Ave, Suite 303, St. Louis, MO 63108 USA.
authors.forename: Guofeng
authors.initials: G
authors.lastname: Fu
authors.affiliation: Array Bridge Inc., 4320 Forest Park Ave, Suite 303, St. Louis, MO 63108 USA.
authors.forename: Xing
authors.identifier: 0000-0003-3720-4237
authors.initials: X
authors.lastname: Wang
authors.affiliation: Zibo Central Hospital, Zibo, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Li
keywords: Biomarkers; Breast cancer; Diagnostic kits; Enzyme activity; Functional proteomics; Hexokinases; Proteases; Protein Elution Plate