Furthermore, the treatment of colorectal cancer cell lines with metformin, an AMPK activator, an HMG-CoA reductase inhibitor, or a mammalian target of rapamycin (mTOR) inhibitor significantly decreased the population of CSCs; however, the number of CSCs rebounded after treatment with mevalonic acid, indicating that mevalonic acid attenuates the inhibitory effect of these treatments on CSCs (Sharon et al., 2015). Here, MTOR is linked to colorectal cancer.