CCND1 and nasopharyngeal carcinoma: The first finding of this study was that KDM4A is expressed at a high level in NPC cells, in which it promotes proliferation, migration, and invasion and inhibits apoptosis; these effects are accompanied by the upregulation of the Ki67, cyclin D1, MMP-2, MMP-9, and Bcl-2 protein expression and the downregulation of Bax protein expression.