Proposed model of how USP2a-driven microRNA deregulation enhances MYC protein expression through impairment of the MDM2–p53 pathway. p53 regulates miR-34b/c expression through promoter enhancement. Proposed model of how USP2a-driven microRNA deregulation enhances MYC protein expression through impairment of the MDM2–p53 pathway. p53 regulates miR-34b/c expression through promoter enhancement. A, when overexpressed, USP2a transcriptionally downregulates miR-34b/c with subsequent MYC activation through MDM2-mediated p53 inactivation. B, low USP2a expression triggers the upregulation of miR-34b/c with subsequent MYC deactivation through MDM2-mediated p53 activation. Barbara Benassi et al. Cancer Discovery 2012;2:236-247 ©2012 by American Association for Cancer Research