The prevalence of genomic HRD in tumors of RAD51C/D PV carriers has mainly been investigated within large cohorts of pan-cancer HRD analysis.21 In a small sample, Li et al22 showed that 7 of 9 cases of RAD51C-associated breast cancer (77.8%) harbored genomic HRD based on a high genomic instability score (GIS) and concomitant gsLOH. Here, RAD51C is linked to breast cancer.