Table 1.

Criteria for study inclusion by study center. CC-HBOC, Cologne Center for Hereditary Breast and Ovarian Cancer; GC-HBOC, German Consortium for Hereditary Breast and Ovarian cancer; IC, Institut Curie; LUMC, Leiden University Medical Center; PV, pathogenic variant.

Study center	Criteria for the study inclusion
CC-HBOC (Germany)	Cancer-free female relatives of index patients, irrespective of the germline PV status of the index patient. All index patients met the inclusion criteria of the German Consortium for Hereditary Breast and Ovarian cancer (GC-HBOC) for germline testing [8].
IC (France)	Cancer-free first degree female relatives of index patients. Index patients carried pathogenic variants in BRCA1, BRCA2, or PALB2.
LUMC (Netherlands)	Cancer-free female relatives of index patients. Index patients were affected with BC and did not carry (likely) pathogenic variants in ATM, BRCA1, BRCA2, CHEK2, or PALB2.