Further, in CSCs isolated from breast and lung carcinomas, or glioblastoma (GBM) [8, 9, 17-21], metformin-dependent cell proliferation arrest does not involve AMPK, but rather the down-regulation of IGF-1 signaling or inhibition of Akt [17, 22, 23]. The gene discussed is IGF1; the disease is glioblastoma.