LEP and breast cancer: While circulating levels of classic pro-inflammatory adipokines and cytokines, such as leptin, resistin, TNF-α, and IL-6, are regularly increased in breast cancer patients, the insulin-sensitizing adiponectin, which exerts anti-proliferative, anti-migratory, and anti-apoptotic effects on tumor cells independent of their HR status, is considered protective against breast carcinogenesis, especially in postmenopausal women [154].