MYCN and retinoblastoma: Classic retinoblastoma‐related chromosome copy number changes, including 1q gain, 6p gain, and 16q loss 2, 11, 12, 13, 14, 15, 16, were observed in 14 (37%), 15 (40%), and seven (18%) tumors (Fig. 3A), respectively; however, there was no significant difference in the fraction of tumors with these copy number changes between MYCN‐amplified and MYCN‐low retinoblastomas (Table 2).