This was largely driven by the increased incidence of TNBC which accounted for 56% of BRCA1 carriers with T1N0 breast cancer (90% of whom received chemotherapy), while only 15.6% of BRCA2 and 40% of PALB2 carriers had T1N0 TNBC (of which 80% and 100% received chemotherapy, respectively; eTable 1). Here, BRCA1 is linked to breast cancer.