MYC and cancer: Following retroviral transduction, we selected a clone expressing MYCER (Figure 1A) that fulfilled two criteria: 1) normal levels of endogenous MYC expression were retained, and 2) MYCER was expressed at levels 2-3 fold higher than endogenous MYC, a level of MYC expression that is appropriate for modeling MYC deregulation in human cancers without MYC amplification [32] (Figure 1A).