BRCA1 and breast cancer: Generally, low frequencies for large rearrangements have been reported in black patients, e.g. Pal et al., [22], detected 2 rearrangements in 144 young African-American women with breast cancer (1.4 %), both of which were in BRCA1. Zhang et al., [42] reported one BRCA1 exon deletion (0.3 %) in a cohort of 352 Nigerian breast cancer patients.