TP53 and neoplasm: However, there was also no significant difference overall in the abundance of the Lynfl allele between BlgCre Brca1fl/fl p53+/− Lynfl/wt and BlgCre Brca1fl/fl p53+/− Lynfl/fl tumour cells (Fig. 3D,F), and it is clear that although in some tumours, the Lynfl allele had recombined effectively, in others, it remained intact (Fig. 3D).