CLIC1 and glioblastoma: In fact, since increased CLIC1 activity is a main regulator of cell proliferation in several tumors, including gastric, colon, and hepato-carcinomas (Peretti et al., 2015), and, of course, GBM (Wang et al., 2012; Setti et al., 2013; Gritti et al., 2014), this mechanism may reconcile the evidence of antitumor activity of metformin (and possibly of other biguanides) on such broad types of neoplasia.