RAD51 foci analyses on a subset of MIND models (n = 20) showed that DCIS accumulate high levels of dsDNA damage (yH2AX foci) and 20% of DCIS PDX are predicted to be homologous recombination deficient (HRD), comparable with the proportion of IBC with genetic HRD signatures and/or genomic scars (Figure S2A).17 This evidence concerns the gene RAD51 and ductal breast carcinoma in situ.