CTNNB1 and neoplasm: To explore the potential of prime editors to drive tumor formation in vivo, we delivered PE2 or PE2*, a pegRNA used for installation (via C-to-T) of the oncogenic S45F mutation in Ctnnb1 (Fig. 4a), and a nicking sgRNA to the livers of adult FVB mice (n = 4/group) by hydrodynamic tail vein injection (Fig. 4b).