The link between obesity and cancer was reported as an increase in leptin, insulin, IGF-1, and pro-inflammatory cytokines, which leads to an activation of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway and mTOR pathway, resulting in the stimulation of proliferation and survival of cancer cells [80]. Here, INS is linked to obesity due to melanocortin 4 receptor deficiency.