Metformin antiproliferative activity in GSCs is mostly dependent on CLIC1 inhibition, whilst loses efficacy in cells in which CLIC1 activity is not required for cell-cycle progression, such as non-stem GBM cells (differentiated cells obtained from GSC cultures shifted in FBS-containing medium) and primary cultures of ucMSCs [6, 27, 38]. The gene discussed is CLIC1; the disease is glioblastoma.