Pioneering this frontier, Naert et al. engineered CRISPR/Cas9 mediated co-knockout of Rb1 and retinoblastoma-like 1 (Rbl1) in Xenopus tropicalis, establishing the non-mammalian genetic RB model exhibiting rapid-onset tumors (minimum 36 days) and high penetrance (73%) 167. Here, RBL1 is linked to retinoblastoma.