PIK3CA and nasopharyngeal carcinoma: Reduction of PTEN dosage by EBV-miR-BART1 activated PTEN-dependent pathways, including PI3-K/Akt, FAK-p130 (Cas), and Shc-MAPK/ERK1/2 signaling, drove EMT, and consequently increased migration, invasion, and metastasis of NPC cells, highlighting the important role of PTEN in EBV-miR-BART-driven metastasis in NPC.274