PTEN and Miyoshi myopathy: Notably, inhibition of miR-221/222 significantly reduced the phosphorylation of AKT, a down-stream target of PTEN and key mediator of tumor cell survival (Fig. 7E), suggesting that the in vivo anti-MM activity of miR-221 inhibitors is related to PTEN up-regulation and impairment of AKT activation within tumors.