In conclusion, the present study reveals that ARID2 negatively regulates cell-cycle progression and cellular proliferation, and represses cyclin D1 and cyclin E1 expression by targeting the Rb-E2F signaling pathway, implying that this tumor suppressor functions as a “gatekeeper.” Further studies are required to investigate whether additional SWI/SNF subunits or transcriptional regulators are implicated in ARID2-mediated gene repression. This evidence concerns the gene RB1 and neoplasm.