About 20 years ago it has been shown that single treatment of mice with the genotoxic tumor initiator N-nitrosodiethylamine followed by chronic treatment with the non-genotoxic tumor-promoting compound phenobarbital, selects for the outgrowth of mouse liver adenoma bearing activating mutations in the Ctnnb1 gene (Aydinlik et al. 2001). Here, CTNNB1 is linked to neoplasm.