MDM4 and retinoblastoma: We highlight MDM4 among the coamplified genes at chromosome 1q32.1 because of its recurrent amplification in RB and biologically validated role in promoting disease progression and potential treatment resistance in studies on RB tumor tissue from enucleated eyes.1,7,8 Other coamplified genes in this region, while of biological interest, lack functional or clinical evidence supporting a role in RB pathogenesis or therapeutic response.