The cut-off value of 10% RAD51+ geminin+ cells (that is, fHR score 10.0) was chosen to define fHRD versus fHRP in chemo-naïve specimens; this value was recently determined to be highly predictive of HRD in a cohort of >100 breast cancer patients, as assessed by PDX-based PARPi sensitivity (28). Here, RAD51 is linked to breast carcinoma.