Body mass index and HER-2 overexpression in breast cancer patients over 50 years of age

Breast Cancer Res Treat. 2007 Nov;106(1):127-33. doi: 10.1007/s10549-006-9474-7. Epub 2007 Jan 9.


Purpose: 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.

Patients and 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.

Conclusion: 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.

MeSH terms

  • Age Factors
  • Aged
  • Aged, 80 and over
  • Body Mass Index*
  • Breast Neoplasms / chemistry*
  • Breast Neoplasms / genetics
  • Breast Neoplasms / physiopathology*
  • Breast Neoplasms / surgery
  • Female
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Immunohistochemistry
  • In Situ Hybridization, Fluorescence
  • Logistic Models
  • Middle Aged
  • Odds Ratio
  • Postmenopause
  • Prospective Studies
  • Receptor, ErbB-2 / analysis*
  • Receptor, ErbB-2 / genetics
  • Receptors, Estrogen / analysis
  • Receptors, Progesterone / analysis
  • Risk Assessment
  • Up-Regulation
  • Waist-Hip Ratio


  • Receptors, Estrogen
  • Receptors, Progesterone
  • ERBB2 protein, human
  • Receptor, ErbB-2