STAT3 and cancer: It has been shown that loss of PIAS3 contributes to STAT3 activation and subsequent cell proliferation in many types of cancer, such as malignant mesothelioma, lung carcinoma, and GBM (Brantley et al., 2008; Dabir et al., 2009, 2014), suggesting that the PIAS3‐STAT3 pathway might also be a signaling pathway that regulates GSC stemness.