POU5F1 and cancer: Binding of IGF1 or IGFII, peptide hormones secreted by many cancer cells and cancer-associated fibroblasts in a autocrine or paracrine manner to extracellular IGF1R domains, enhances expression of biomarkers involved in stemness, such as Nanog, Sox2, and Oct3/4 via cytoplasmic IGF1Rβ activation and IGF1Rβ downstream signaling activation pathways, including PI3K/AKT pathways [34,48,49].