Nonsense or frameshift mutations, which result in the truncated gene product (and presumably non-functional or dysfunctional BRCA protein), account for approximately 90% of the clinically important BRCA1/2 entries in the Breast Cancer Information Core (BIC) database and approximately 50% fall within the large exon 11 (of BRCA1 and BRCA2) alone [6]. This evidence concerns the gene BRCA1 and breast cancer.