BRCA1 and breast cancer: However, Bogdani et al.[29] using D-20, K-18, I-20, and C-20 anti-BRCA1 antibodies on Bouin’s fixed tumor tissue of young and old patients with breast cancer, found nuclear and cytoplasmic BRCA1 staining in about 50% of sporadic specimens, and less staining in tumor cells in young patients and one with a germline mutation.