Obesity increases systemic levels as well as cellular secretion of many cytokines and adipokines including leptin, IL6, TNFα, IGF1, fatty acid binding protein 4 (FABP4), and resistin, which are all involved in regulating the pathways associated with the development of CSCs in breast cancer tissue [202]. Here, FABP4 is linked to obesity due to melanocortin 4 receptor deficiency.