Although not examined in this study, others have recently observed an increased need for transfusions and lower blood counts among individuals receiving chemotherapy who have evidence of clonal hematopoiesis (CH) in their blood.20 Given that CH is also a risk factor for future hematologic malignancy development,21 the incidence of this finding at baseline as well as following chemotherapy in BRCA1 and BRCA2 carriers vs individuals without a mutation during chemotherapy warrants further investigation. Here, BRCA1 is linked to cyclic hematopoiesis.