ABSTRACT
Obesity, defined as Body Mass Index (BMI) ss30, constitutes a known risk factor for the development o f different neoplasms, including such common diseases as postmenopausal breast cancer and colorectal cancer.1 According to the N ational Cancer Institute sig nificant excess o f body weight increases the risk o f postmenopausal breast cancer by 30-50%, while the risk o f colorectal cancer is elevated by 50-100% in man and 20-50% in women. The exact mechanism o f the obesity-cancer link is no t clear, but ongoing research points to the im portant role o f different biologically active substances produced by the adipose tissue. Among them, mitogenic growth factors, steroid hormones, fatty acids and interleukins stand out as chief culprits.1'10 The impact o f mitogens such as insulin-like growth factor (IGF-1), or steroids, such as estrogens, in epithelial oncogenesis has been well docum ented.1,10·14 However, the function o f leptin, the principal cytokine produced by fat cells and directly associated w ith adiposity and BMI,4,15 is still quite obscure.8
