In addition, miR21 (as well as miR155) has been recently shown to be upregulated in focal cortical dysplasia (FCD) tissue samples [61] and in cortical tubers of patients with tuberous sclerosis complex (TSC; van Scheppingen et al., unpublished observations), suggesting an epigenetic regulation of the mammalian target of rapamycin (mTOR) signaling pathway, which is also activated in GGs [10]. Here, MTOR is linked to tuberous sclerosis.