We examined epigenetic and genomic levels for a detailed molecular view of subtypes 1 and 2 in a cohort of 61 primary retinoblastoma samples enriched by 6 RB1-proficient MYCNA retinoblastoma samples (4 previously described25) and 2 samples of relapsed, extraocular retinoblastomas (Supplementary Data 1, 2). Here, RB1 is linked to retinoblastoma.