Unlike rodent models, paediatric xenograft brain tumour modelling in zebrafish is rapid, with engraftment in embryos observed at 3 dpf following transplantation on 2 dpf embryos, whereas adult Casper il2rgc.a−/−; prkdc−/− strain takes about 7–10 days for tumour engraftment. The gene discussed is CFLAR; the disease is brain neoplasm.