title: Biomarkers associated with breast cancer are associated with obesity.
abstract: BACKGROUND
  Obesity is linked to the development of postmenopausal breast cancer, and some studies indicate obesity predicts a worse prognosis for premenopausal women who develop the disease. It was our hypothesis that proteins associated with breast cancer would be associated with body mass index (BMI).
  
  
  METHODS
  We searched our database of women enrolled in breast health translational research trials for information on BMI and markers predictive of breast cancer (basic fibroblast growth factor (bFGF), prostate-specific antigen (PSA), human kallikrein (hK)2, and urinary plasminogen activator (uPA). Information on BMI and one or more nipple aspirate fluid (NAF) or serum biomarkers was available from 382 women.
  
  
  RESULTS
  In this data set, NAF and serum levels of PSA (nPSA and sPSA), and NAF levels hK2, bFGF and uPA were each associated with pre- and/or postmenopausal breast cancer. sPSA was inversely associated with BMI in both pre- (r=-.56, p=.001) and postmenopausal women (r=-.62, p=.0035) without breast cancer. This association was lost when controlling for plasma volume. In women without breast cancer, NAF bFGF (p=.07, premenopausal subjects) and NAF hK2 (p=.09, postmenopausal subjects) were borderline associated with BMI. In women with breast cancer, nPSA was inversely (r=-.53, p=.049) associated with BMI in premenopausal women and directly associated with BMI in postmenopausal women (r=.37, p=.017). nPSA trended higher in hormone sensitive cancers, especially those that expressed progesterone receptor (p=.059).
  
  
  CONCLUSIONS
  sPSA was inversely associated with BMI in all pre- and postmenopausal women and specifically in pre- and postmenopausal women without breast cancer. NAF PSA was associated with BMI in pre- and postmenopausal women with breast cancer. Evaluating the change in PSA with changes in weight may provide clues regarding a subject's breast cancer risk.
authors.affiliation: Department of Surgery, University of Missouri, One Hospital Drive, Columbia, MO 65212, USA. sautere@health.missouri.edu
authors.forename: Edward R
authors.initials: ER
authors.lastname: Sauter
authors.forename: Stephen
authors.initials: S
authors.lastname: Scott
authors.forename: John
authors.initials: J
authors.lastname: Hewett
authors.forename: Beth
authors.initials: B
authors.lastname: Kliethermes
authors.forename: Rachel L
authors.initials: RL
authors.lastname: Ruhlen
authors.forename: Krishnamohan
authors.initials: K
authors.lastname: Basarakodu
authors.forename: Roger
authors.initials: R
authors.lastname: de la Torre
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D001826:Body Fluids / Q000737:chemistry; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000150:complications* / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D016222:Fibroblast Growth Factor 2 / Q000032:analysis; D018734:Genes, erbB-2; D006801:Humans; D008875:Middle Aged; D009558:Nipples; D009765:Obesity / Q000150:complications* / Q000378:metabolism*; D017698:Postmenopause; D017697:Premenopause; D011379:Prognosis; D017430:Prostate-Specific Antigen / Q000032:analysis; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D020840:Tissue Kallikreins / Q000032:analysis; D014568:Urokinase-Type Plasminogen Activator / Q000032:analysis
chemical_list: D014408:Biomarkers, Tumor; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D016222:Fibroblast Growth Factor 2; D020840:Tissue Kallikreins; D014568:Urokinase-Type Plasminogen Activator; D017430:Prostate-Specific Antigen