BRCA1 and Hereditary breast and ovarian cancer syndrome: The prospective cohort study of the German Consortium Hereditary Breast and Ovarian Cancer (GC-HBOC) is conducting the HerediCaRe registry, which is part of the International BRCA1 and BRCA2 Carrier Cohort Study (IBCCS) [37], one of the largest registries for hereditary breast and ovarian cancer.