In addition, IL-6 treatment induced IGF-1 secretion and IGF-1R expression in NANOG/OCT4-HCC cell lines in a dose-dependent manner [134], suggesting crosstalk between IL-6/STAT3 signaling and IGF/IGF-1R signaling in HCC cancer stem cells (Figure 2). Here, STAT3 is linked to hepatocellular carcinoma.