Functions of Obesity-related Hormones in Breast Cancer: A Review

ABSTRACT Obesity is a health problem defined as abnormal or excessive fat accumulation in adipose tissue. Adipokines such as adiponectin, visfatin and resistin are bioactive polypeptides with pro- and anti-inflammatory properties that are secreted by the adipose tissue that are involved in the pathogenesis and prognosis of diseases such as type 2 diabetes, metabolic syndrome and cancer. This survey aimed to review the role of these hormones in the pathogenesis and prognosis of breast cancer in obese postmenopausal women. In obese individuals, increased level of leptin leads to tumorigenesis and progression of breast cancer though JAK/STAT3 pathway. These individuals have decreased level of adiponectin, which has a protective effect against carcinogenesis via AMPK pathway. Obese individuals also have increased level of visfatin, which induces the secretion of proinflammatory cytokines such as TNFα and triggers growth of cancer cells. Similarly, elevated resistin levels increases cell proliferation through PI3K and MAPK pathways. Obesity is associated with the dysregulated secretion of adipokines such as leptin, adiponectin, visfatin and resistin, which could be utilized for early diagnosis of breast cancer. Keywords: Obesity, Breast Cancer, Adiponectin, Leptin, Visfatin, Resistin