PTEN and breast cancer: To further confirm that PI3K/AKT pathway activation and EMT of HK-2 cells caused by miR-214-3p overexpression were achieved through PTEN downregulation, EMT cells stimulated by TGF-β1 were divided into four groups and cotransfected with LV − NC − OE + BC, LV − NC − OE + PTEN OE, LV − miR − 214 − OE + BC, and LV − miR − 214 − OE + PTEN OE.