Abstract B50: Leptin and leptin receptor expression in breast cancer

Abstract

Abstract Background: Leptin is a multifunctional hormone produced by the adipose tissue and involved in the regulation of food intake and energy balance. The aims of this study is to evaluate leptin and leptin receptor (Ob-R) expression in human breast cancer and determine whether it influence the prognosis of the patients with breast cancers. Methods: We examined the correlation for leptin and Ob-R expression and breast cancer-related pathobiological markers by immunohistochemistry in five hundred and seventeen patients with breast cancer. We analyzed leptin and leptin receptor (Ob-R) expression for overall survival (OS) and relapse-free survival (RFS). Results: Positive cytoplasmic immunoreactivity was found in 39% for leptin and 79% for Ob-R. The expression of leptin in breast cancer correlated with high Ki-67 labeling index (p=0.019). The leptin expression showed significant correlation with triple negative (TN) type (p=0.022) and epidermal growth factor receptor (EGFR) reactivity (p=0.05). The frequency of Ob-R expression was higher in non-TN breast cancers (p=0.045) and the breast cancers with high Ki-67 labeling index (p=0.06). In univariate survival analysis, clinicopathologic variables with prognostic value included histologic grade, T stage, N stage, HER2 status, Bcl-2, p53, and Ki-67 expression (p<0.05). The patients with leptin-positive breast cancers showed longer OS in negative hormone receptor status. In multivariate survival analysis with Cox proportional hazards model, leptin expression was independent prognostic marker (Hazard ratio=0.22, 95% CI 0.06 and 0.79, p=0.02) in hormone receptor negative breast cancers. Conclusion: We conclude that leptin leptin expression in breast cancers is significantly associated with Ki-67 labeling index, suggesting association with proliferation activity. In addition, leptin expression is a indicator of favorable tumor features and better survival of hormone receptor negative breast cancer patients. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B50.