TP53 and cancer: Most likely, tert−/− tp53−/− zebrafish will display an abnormally high incidence of cancer and early onset of tumors, given that these features characterize the single tp53−/− mutants [28% of fish develop malignant peripheral-nerve-sheath tumors by 8 months (Berghmans et al., 2005)] and the single tert−/− mutants (where cancer appears as early as 4 months) (Carneiro et al., 2016).