RAD51 and neoplasm: Finally, these results show that in the 3 PDX models with partial BRCA1 methylation (HBCx-24, HBCx-40, HBCx-1) (Fig. 2d) cisplatin treatment results in increased levels of RAD51 foci (Fig. 3b), further supporting the hypothesis that these tumours are not deficient in HR repair, in spite of the genomic scar of HRD and the biallelic inactivation of BRCA1. Conversely, 5/6 PDX with complete BRCA1 inactivation do not show any increase of RAD51 levels upon cisplatin treatment and thus can be considered as HR deficient.