Deletion of exon 2 and 3 eliminates the natural transcription start site of CTNNB1. In order to investigate the functional impact of the ∆(2 + 3) deletion on the protein product, β-Catenin, we performed Western blot analysis on the tumour protein lysates, which demonstrated expression of wildtype as well as truncated protein in samples harbouring the ∆(2 + 3) deletion (Fig. 3a). This evidence concerns the gene CTNNB1 and neoplasm.