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

• Published in: Breast cancer research and treatment 2007-11, Vol.106 (1), p.127-133
• Main Authors: VAN MIEGHEM, T, LEUNEN, K, WILDIERS, H, PARIDAENS, R, SMEETS, A, HENDRICKX, W, VAN LIMBERGEN, E, CHRISTIAENS, M. R, VERGOTE, I, NEVEN, P, POCHET, N, DE MOOR, B, DE SMET, F, AMANT, F, BERTELOOT, P, TIMMERMAN, D, VANDEN BEMPT, I, DRIJKONINGEN, R
• Format: Article
• Language: English
• Subjects: Age Factors; Aged; Aged, 80 and over; Biological and medical sciences; Body fat; Body Mass Index; Breast cancer; Breast Neoplasms - chemistry; Breast Neoplasms - genetics; Breast Neoplasms - physiopathology; Breast Neoplasms - surgery; Cancer research; Cancer therapies; Estrogens; Female; Gene expression; Gene Expression Regulation, Neoplastic; Gynecology. Andrology. Obstetrics; Humans; Immunohistochemistry; In Situ Hybridization, Fluorescence; Logistic Models; Mammary gland diseases; Medical sciences; Metabolic diseases; Middle Aged; Obesity; Odds Ratio; Older people; Oncology; Postmenopause; Prospective Studies; Receptor, ErbB-2 - analysis; Receptor, ErbB-2 - genetics; Receptors, Estrogen - analysis; Receptors, Progesterone - analysis; Risk Assessment; Tumors; Up-Regulation; Waist-Hip Ratio; Weight
• ISSN: 0167-6806; 1573-7217
• DOI: 10.1007/s10549-006-9474-7

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. 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. 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. 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.