MMP9 and nasopharyngeal carcinoma: NPC cells were transfected with pEGFP-CTF2 or pEGFP-C1 (empty vector with EGFP) along with pGL-MMP9-Luc for 24 h and examined for PMA-inducedMMP-9 expression in NPC cells expressing an exogenous CTF2 domain (with EGFP) (~60 kDa) (Fig. 9c).