Role of adipokines and cytokines in obesity-associated breast cancer: Therapeutic targets

Obesity is the cause of a large proportion of breast cancer incidences and mortality in post-menopausal women. In obese people, elevated levels of various growth factors such as insulin and insulin-like growth factors (IGFs) are found. Elevated insulin level leads to increased secretion of estrogen by binding to the circulating sex hormone binding globulin (SHBG). The increased estrogen-mediated downstream signaling favors breast carcinogenesis. Obesity leads to altered expression profiles of various adipokines and cytokines including leptin, adiponectin, IL-6, TNF-α and IL-1β. The increased levels of leptin and decreased adiponectin secretion are directly associated with breast cancer development. Increased levels of pro-inflammatory cytokines within the tumor microenvironment promote tumor development. Efficacy of available breast cancer drugs against obesity-associated breast cancer is yet to be confirmed. In this review, we will discuss different adipokine- and cytokine-mediated molecular signaling pathways involved in obesity-associated breast cancer, available therapeutic strategies and potential therapeutic targets for obesity-associated breast cancer.