ERBB2 and breast carcinoma: MiR-221/222 might inhibit the cell-cycle inhibitor, p27Kip1, a downstream modulator of PI3KCI/Akt, leading to autophagic cell death in HER2/neu-positive primary human breast carcinoma MCF-7 cells, whereas the ectopic expression of miR-221/222 renders the parental MCF-7 cells resistant to tamoxifen [66, 67].