title: Body mass index and HER-2 overexpression in breast cancer patients over 50 years of age.
abstract: OBJECTIVE
  In breast cancer, in vitro as well as in vivo experiments have shown an inverse relationship between HER-2 and steroid hormone receptors. It is unknown whether circulating estrogens affect HER-2 expression. We hypothesize that the postmenopausal body mass index (BMI) as a surrogate marker for bio-available estrogens, is inversely associated with HER-2 over-expression.
  
  
  METHODS
  A total of 535 women over age 50 or with known postmenopausal status, with a unilateral, not previously treated, operable breast cancer were evaluated the evening prior to surgery for body weight, height, abdominal and hip circumference over a 3 years period. Waist-to-hip ratio (WHR) and BMI were calculated. HER-2, estrogen receptor and progesterone receptor staining was done by immunohistochemistry. All tumours with DAKO 2+ staining were submitted for HER-2 detection by FISH analysis. HER-2 was defined as positive if DAKO 3+ or FISH positive. We assessed the frequency of HER-2 positivity in each of 6 quantiles for all parameters of body composition and tested for a trend in HER-2 expression across the 6 quantiles. Furthermore, we investigated whether BMI contributed, together with other known predictors for HER-2, in a standard multivariate logistic regression model that predicts HER-2 over-expression.
  
  
  RESULTS
  There is a decrease in HER-2 over-expression per increasing quantile of BMI. In a multivariate model-including both steroid receptors-BMI remains an independent predictor for HER-2 over-expression.
  
  
  CONCLUSIONS
  In women over age 50 or with known postmenopausal status with an operable breast cancer, there is an inverse association between BMI and HER-2 over-expression.
authors.affiliation: Department of Obstetrics and Gynaecology, University Hospitals Leuven, Herestraat 49, 3000, Leuven, Belgium.
authors.forename: T
authors.initials: T
authors.lastname: Van Mieghem
authors.forename: K
authors.initials: K
authors.lastname: Leunen
authors.forename: N
authors.initials: N
authors.lastname: Pochet
authors.forename: B
authors.initials: B
authors.lastname: De Moor
authors.forename: F
authors.initials: F
authors.lastname: De Smet
authors.forename: F
authors.initials: F
authors.lastname: Amant
authors.forename: P
authors.initials: P
authors.lastname: Berteloot
authors.forename: D
authors.initials: D
authors.lastname: Timmerman
authors.forename: I
authors.initials: I
authors.lastname: Vanden Bempt
authors.forename: R
authors.initials: R
authors.lastname: Drijkoningen
authors.forename: H
authors.initials: H
authors.lastname: Wildiers
authors.forename: R
authors.initials: R
authors.lastname: Paridaens
authors.forename: A
authors.initials: A
authors.lastname: Smeets
authors.forename: W
authors.initials: W
authors.lastname: Hendrickx
authors.forename: E
authors.initials: E
authors.lastname: Van Limbergen
authors.forename: M R
authors.initials: MR
authors.lastname: Christiaens
authors.forename: I
authors.initials: I
authors.lastname: Vergote
authors.forename: P
authors.initials: P
authors.lastname: Neven
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000737:chemistry* / Q000235:genetics / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D016015:Logistic Models; D008875:Middle Aged; D016017:Odds Ratio; D017698:Postmenopause; D011446:Prospective Studies; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis* / Q000235:genetics; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis; D018570:Risk Assessment; D015854:Up-Regulation; D049629:Waist-Hip Ratio
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human