PSMB9 and nasopharyngeal carcinoma: The ERK1/2 pathway participates in raising the production of transcription factor Fra-1 and the level of MMP9; on the other hand, LMP2 and LMP1 phosphorylate 4EBP1 through the PI3K/Akt/mTOR signaling to elevate the expression of metastatic tumor antigen 1 (MTA1), thereby, expediting the invasiveness and metastatic ability of the NPC cells 2,58,59.