BRCA1 and breast cancer: Figure 2 shows the promoter methylation in sporadic breast cancer patients. Methylation was positive in 82.6% (n=19/23) of the sporadic cancer samples that had loss of BRCA1 expression and 50% (n=2/4) of the samples with equivocal protein expression. Methylation was negative in all the sporadic breast cancer samples (n=3/3) with retained protein expression. Consistent with the BRCA1 promoter methylation, the protein expression levels of BRCA1 were reduced in sporadic breast tumors with methylated genes.