MTOR and plasma cell myeloma: Wang et al. showed that metformin, as a potential specific dual mTORC1/2 inhibitor, downregulates p-mTOR (Se-2448), p-P70 S6K, p-4 EBP1, and p-AKT (Ser 473) expression through AMPK activation-mediated mTORC1/mTORC2 inhibition, induces autophagy, and causes cell cycle arrest in the G0/G1 phase of myeloma cells, which ultimately inhibits the growth of myeloma cells (54).