The study subjects are composed of postmenopausal women with hormone receptor-positive breast cancer who have received exemestane, anastrozole or letrozole followed by testing of safety variables such as low-density lipoprotein- cholesterol (LDL-C), triglyceride(TC), total cholesterol, high-density lipoprotein cholesterol(HDL), blood calcium, transaminase and fasting plasma glucose at different time intervals in two years.