Although RB1 was mutated in about one-third of our retinoblastoma cases, RB1 mutation-negative retinoblastoma patients had germline P/LP variants in other known cancer predisposition genes like BRCA1 (2), EGFR (1), and MSH6 (1) (Fig. 3a, b). This evidence concerns the gene BRCA1 and retinoblastoma.