TP53 and nasopharyngeal carcinoma: MEG3 also increased expression of p53 and a potent cyclin-dependent kinase inhibitor called p21, which might explain the observed enhancement of G1/S cell cycle arrest, and stimulated E3 ubiquitin ligase MDM2 production, which could represent suppressed NPC metastasis through the p53-MDM2-Slug pathway (74).