In addition, the mitogen-activated protein kinase (MAPK) insulin pathway is the basis of many obesity-related malignancies that control cell growth and mitosis (36), whereas insulin can directly promote cell proliferation and survival via the phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt) and Ras/MAPK pathways (37). Here, INS is linked to obesity due to melanocortin 4 receptor deficiency.