Within the recurrent focal gains or losses in the RbTKO retinoblastoma model, we found 12 in cancer genes, including Lmo1 in 5/6 samples; Ndrg1, Brd4, Fbxo11, and Rbm15 in 4/6 samples; Mdm4, Msi2, and Ezh2 in 3/6 samples. The gene discussed is MDM4; the disease is cancer.