TP53 and neoplasm: To test the functional role of the TP53 mutation identified in the malignant recurrent tumour, we generated Hesx1Cre/+; Ctnnb1lox(ex3)/+; Trp53+/+, Hesx1Cre/+; Ctnnb1lox(ex3)/+; Trp53fl/+ and Hesx1Cre/+; Ctnnb1lox(ex3)/+; Trp53fl/fl mice with either wild-type Trp53, heterozygous or homozygous deletion of Trp53, respectively.