title: Proteomic risk markers for coronary heart disease and stroke: validation and mediation of randomized trial hormone therapy effects on these diseases.
abstract: BACKGROUND
  We previously reported mass spectrometry-based proteomic discovery research to identify novel plasma proteins related to the risk of coronary heart disease (CHD) and stroke, and to identify proteins with concentrations affected by the use of postmenopausal hormone therapy. Here we report CHD and stroke risk validation studies for highly ranked proteins, and consider the extent to which protein concentration changes relate to disease risk or provide an explanation for hormone therapy effects on these outcomes.
  
  
  METHODS
  Five proteins potentially associated with CHD (beta-2 microglobulin (B2M), alpha-1-acid glycoprotein 1 (ORM1), thrombospondin-1(THBS1), complement factor D pre-protein (CFD), and insulin-like growth factor binding protein 1 (IGFBP1)) and five potentially associated with stroke (B2M, IGFBP2, IGFBP4, IGFBP6, and hemopexin (HPX)) had high discovery phase significance level ranking and an available ELISA assay, and were included in case-control validation studies within the Women's Health Initiative (WHI) hormone therapy trials. Protein concentrations, at baseline and 1 year following randomization, were assessed for 358 CHD cases and 362 stroke cases, along with corresponding disease-free controls. Disease association, and mediation of estrogen-alone and estrogen plus progestin effects on CHD and stroke risk, were assessed using logistic regression.
  
  
  RESULTS
  B2M, THBS1, and CFD were confirmed (P <0.05) as novel CHD risk markers, and B2M, IGFBP2, and IGFBP4 were confirmed as novel stroke disease risk markers, while the assay for HPX proved to be unreliable. The change from baseline to 1 year in B2M was associated (P <0.05) with subsequent stroke risk, and trended similarly with subsequent CHD risk. Change from baseline to 1 year in IGFBP1 was also associated with CHD risk, and this change provided evidence of hormone therapy effect mediation.
  
  
  CONCLUSIONS
  Plasma B2M is confirmed to be an informative risk marker for both CHD and stroke. The B2M increase experienced by women during the first year of hormone therapy trial participation conveys cardiovascular disease risk. The increase in IGFBP1 similarly conveys CHD risk, and the magnitude of the IGFBP1 increase following hormone therapy may be a mediator of hormone therapy effects. Plasma THBS1 and CFD are confirmed as CHD risk markers, and plasma IGFBP4 and IGFBP2 are confirmed as stroke risk markers.
  
  
  BACKGROUND
  ClinicalTrials.gov identifier: NCT00000611.
authors.affiliation: Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, P.O. Box 19024, Seattle, WA 98109, USA.
authors.forename: Ross L
authors.initials: RL
authors.lastname: Prentice
authors.affiliation: Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, P.O. Box 19024, Seattle, WA 98109, USA.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Zhao
authors.affiliation: Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, P.O. Box 19024, Seattle, WA 98109, USA.
authors.forename: Melissa
authors.initials: M
authors.lastname: Johnson
authors.affiliation: Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, P.O. Box 19024, Seattle, WA 98109, USA.
authors.forename: Aaron
authors.initials: A
authors.lastname: Aragaki
authors.affiliation: Research and Development, AstraZeneca LP, 1971 Rockland Road, Wilmington, DE 19803, USA.
authors.forename: Judith
authors.initials: J
authors.lastname: Hsia
authors.affiliation: Division of Endocrinology, The Ohio State University, 376 West Tenth Avenue, Suite 205, Columbus, OH 43210, USA.
authors.forename: Rebecca D
authors.initials: RD
authors.lastname: Jackson
authors.affiliation: WHI Project Office, National Heart, Lung, and Blood Institute, National Institutes of Health, 6701 Rockledge Drive, Bethesda, MD 20892, USA.
authors.forename: Jacques E
authors.initials: JE
authors.lastname: Rossouw
authors.affiliation: Division of Preventive Medicine, Brigham and Women's Hospital, Harvard Medical School, 900 Commonwealth Avenue, Boston, MA 02215, USA.
authors.forename: JoAnn E
authors.initials: JE
authors.lastname: Manson
authors.affiliation: Department of Clinical Cancer Prevention, Red and Charline McCombs Institute for the Early Detection and Treatment of Cancer, The University of Texas MD Anderson Cancer Center, 6767 Bertner Street, Houston, TX 77030, USA.
authors.forename: Samir M
authors.initials: SM
authors.lastname: Hanash