CTNNB1 and neoplasm: 32). The surrounding kidney was shown to be absent for CTNNB1 mutation or LOH. These data support CTNNB1 mutation being a later event in WT tumourigenesis, which is further supported by the fact that new bilateral WTs subsequently developed with novel CTNNB1 mutations (S45C on the right; S45F on the left) (Ref. 32). A separate study that showed three of five tumours within one patient had different CTNNB1 mutations (delta45, S45C and S45P) (Ref. 33).