AR and prostate cancer: As indicated by early studies, androgen/AR signaling could induce the expression of protein inhibitor of activated STAT3 (PIAS3), which could suppress the STAT3 activation in prostate cancer.23 Thus, we checked the expression level of PIAS3 and it was found that PIAS3 was decreased by sorafenib treatment, which possibly contributed to the increase of pSTAT3 (Y705) (Figure 1g).