Immunohistochemical study of ER, PR and HER2 expression in obese and non-obese menopausal women with breast cancer

ABSTRACT

Objective: Analyze the estrogen receptor (ER), progesterone receptor (PR) and HER2 in obese and non-obese postmenopausal patients with breast cancer. Materials and Methods: A retrospective cross-sectional study was carried out in 163 postmenopausal patients with breast cancer at the mastology clinic of the Regional Hospital of Maringá State University and a private mastology clinic from January 2002 to December 2006. A bivariate analysis was used with the non-parametric tests Chi-square and Fisher’s exact. For obesity calculation, the body mass index (BMI) was used based on the Latin American Obesity Consensus (1999) and on the World Health Organization (1998). Immunohistochemical techniques were performed for ER and PR detection and FISH and CISH methods for HER2 detection. Results: Positive ER in 84 percent of the patients (59 percent in non-obese and 25 percent in obese). A negative result was found in 16 percent of the total of patients (11 percent in non-obese and 5 percent in obese). PR was positive in 76 percent of the total (53 percent in non-obese and 23 percent in obese), and negative in 24 percent (17 percent in non-obese and 7 percent in obese).The overexpression of HER2 was positive in 18 percent (14 percent in non-obese and 4 percent in obese), and negative in 82 percent (56 percent in non- obese and 26 percent in obese).The body mass index cross-comparison with the variables ER, PR and HER2 showed all p-values greater than 0.05 (95 percent CI). Therefore, they are not statistically significant. Conclusions: No significant difference was found between ER and PR among the obese and non-obese patients (p>0.05). No relevant difference was found in HER2 hyperexpression among obese women (p>0.05).